[PATCH v7 02/15] hw/display/apple-gfx: Introduce ParavirtualizedGraphics.Framework support

Phil Dennis-Jordan posted 15 patches 2 weeks, 4 days ago
There is a newer version of this series
[PATCH v7 02/15] hw/display/apple-gfx: Introduce ParavirtualizedGraphics.Framework support
Posted by Phil Dennis-Jordan 2 weeks, 4 days ago
MacOS provides a framework (library) that allows any vmm to implement a
paravirtualized 3d graphics passthrough to the host metal stack called
ParavirtualizedGraphics.Framework (PVG). The library abstracts away
almost every aspect of the paravirtualized device model and only provides
and receives callbacks on MMIO access as well as to share memory address
space between the VM and PVG.

This patch implements a QEMU device that drives PVG for the VMApple
variant of it.

Signed-off-by: Alexander Graf <graf@amazon.com>
Co-authored-by: Alexander Graf <graf@amazon.com>

Subsequent changes:

 * Cherry-pick/rebase conflict fixes, API use updates.
 * Moved from hw/vmapple/ (useful outside that machine type)
 * Overhaul of threading model, many thread safety improvements.
 * Asynchronous rendering.
 * Memory and object lifetime fixes.
 * Refactoring to split generic and (vmapple) MMIO variant specific
   code.

Implementation wise, most of the complexity lies in the differing threading
models of ParavirtualizedGraphics.framework, which uses libdispatch and
internal locks, versus QEMU, which heavily uses the BQL, especially during
memory-mapped device I/O. Great care has therefore been taken to prevent
deadlocks by never calling into PVG methods while holding the BQL, and
similarly never acquiring the BQL in a callback from PVG. Different strategies
have been used (libdispatch, blocking and non-blocking BHs, RCU, etc.)
depending on the specific requirements at each framework entry and exit point.

Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
---

v2:

 * Cherry-pick/rebase conflict fixes
 * BQL function renaming
 * Moved from hw/vmapple/ (useful outside that machine type)
 * Code review comments: Switched to DEFINE_TYPES macro & little endian
   MMIO.
 * Removed some dead/superfluous code
 * Mad set_mode thread & memory safe
 * Added migration blocker due to lack of (de-)serialisation.
 * Fixes to ObjC refcounting and autorelease pool usage.
 * Fixed ObjC new/init misuse
 * Switched to ObjC category extension for private property.
 * Simplified task memory mapping and made it thread safe.
 * Refactoring to split generic and vmapple MMIO variant specific
   code.
 * Switched to asynchronous MMIO writes on x86-64
 * Rendering and graphics update are now done asynchronously
 * Fixed cursor handling
 * Coding convention fixes
 * Removed software cursor compositing

v3:

 * Rebased on latest upstream, fixed breakages including switching to Resettable methods.
 * Squashed patches dealing with dGPUs, MMIO area size, and GPU picking.
 * Allow re-entrant MMIO; this simplifies the code and solves the divergence
   between x86-64 and arm64 variants.

v4:

 * Renamed '-vmapple' device variant to '-mmio'
 * MMIO device type now requires aarch64 host and guest
 * Complete overhaul of the glue code for making Qemu's and
   ParavirtualizedGraphics.framework's threading and synchronisation models
   work together. Calls into PVG are from dispatch queues while the
   BQL-holding initiating thread processes AIO context events; callbacks from
   PVG are scheduled as BHs on the BQL/main AIO context, awaiting completion
   where necessary.
 * Guest frame rendering state is covered by the BQL, with only the PVG calls
   outside the lock, and serialised on the named render_queue.
 * Simplified logic for dropping frames in-flight during mode changes, fixed
   bug in pending frames logic.
 * Addressed smaller code review notes such as: function naming, object type
   declarations, type names/declarations/casts, code formatting, #include
   order, over-cautious ObjC retain/release, what goes in init vs realize,
   etc.

v5:

 * Smaller non-functional fixes in response to review comments, such as using
   NULL for the AIO_WAIT_WHILE context argument, type name formatting,
   deleting leftover debug code, logging improvements, state struct field
   order and documentation improvements, etc.
 * Instead of a single condition variable for all synchronous BH job types,
   there is now one for each callback block. This reduces the number
   of threads being awoken unnecessarily to near zero.
 * MMIO device variant: Unified the BH job for raising interrupts.
 * Use DMA APIs for PVG framework's guest memory read requests.
 * Thread safety improvements: ensure mutable AppleGFXState fields are not
   accessed outside the appropriate lock. Added dedicated mutex for the task
   list.
 * Retain references to MemoryRegions for which there exist mappings in each
   PGTask, and for IOSurface mappings.

v6:

 * Switched PGTask_s's' mapped_regions from GPtrArray to GArray
 * Allow DisplaySurface to manage its own vram now that texture -> vram copy
   occurs under BQL.
 * Memory mapping operations now use RCU_READ_LOCK_GUARD() where possible
   instead of a heavy-weight BH job to acquire the BQL.
 * Changed PVG cursor and mode setting callbacks to kick off BHs instead of
   libdispatch tasks which then locked the BQL explicitly.
 * The single remaining callback which must wait for a BH to complete now
   creates an ephemeral QemuSemaphore to await completion.
 * Re-removed tracking of mapped surface manager memory regions. Just look up
   and ref/unref the memory regions in the map/unmap callbacks.
 * Re-ordered functions in apple-gfx.m to group them by area of functionality.
 * Improved comments and tweaked some names.

v7:

 * Use g_ptr_array_find() helper function
 * Error handling coding style tweak

 hw/display/Kconfig          |   9 +
 hw/display/apple-gfx-mmio.m | 281 +++++++++++++
 hw/display/apple-gfx.h      |  65 +++
 hw/display/apple-gfx.m      | 770 ++++++++++++++++++++++++++++++++++++
 hw/display/meson.build      |   4 +
 hw/display/trace-events     |  28 ++
 meson.build                 |   4 +
 7 files changed, 1161 insertions(+)
 create mode 100644 hw/display/apple-gfx-mmio.m
 create mode 100644 hw/display/apple-gfx.h
 create mode 100644 hw/display/apple-gfx.m

diff --git a/hw/display/Kconfig b/hw/display/Kconfig
index 2250c740078..6a9b7b19ada 100644
--- a/hw/display/Kconfig
+++ b/hw/display/Kconfig
@@ -140,3 +140,12 @@ config XLNX_DISPLAYPORT
 
 config DM163
     bool
+
+config MAC_PVG
+    bool
+    default y
+
+config MAC_PVG_MMIO
+    bool
+    depends on MAC_PVG && AARCH64
+
diff --git a/hw/display/apple-gfx-mmio.m b/hw/display/apple-gfx-mmio.m
new file mode 100644
index 00000000000..10f52b0797b
--- /dev/null
+++ b/hw/display/apple-gfx-mmio.m
@@ -0,0 +1,281 @@
+/*
+ * QEMU Apple ParavirtualizedGraphics.framework device, MMIO (arm64) variant
+ *
+ * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * ParavirtualizedGraphics.framework is a set of libraries that macOS provides
+ * which implements 3d graphics passthrough to the host as well as a
+ * proprietary guest communication channel to drive it. This device model
+ * implements support to drive that library from within QEMU as an MMIO-based
+ * system device for macOS on arm64 VMs.
+ */
+
+#include "qemu/osdep.h"
+#import <ParavirtualizedGraphics/ParavirtualizedGraphics.h>
+#include "apple-gfx.h"
+#include "monitor/monitor.h"
+#include "hw/sysbus.h"
+#include "hw/irq.h"
+#include "trace.h"
+#include "qemu/log.h"
+
+OBJECT_DECLARE_SIMPLE_TYPE(AppleGFXMMIOState, APPLE_GFX_MMIO)
+
+/*
+ * ParavirtualizedGraphics.Framework only ships header files for the PCI
+ * variant which does not include IOSFC descriptors and host devices. We add
+ * their definitions here so that we can also work with the ARM version.
+ */
+typedef bool(^IOSFCRaiseInterrupt)(uint32_t vector);
+typedef bool(^IOSFCUnmapMemory)(
+    void *, void *, void *, void *, void *, void *);
+typedef bool(^IOSFCMapMemory)(
+    uint64_t phys, uint64_t len, bool ro, void **va, void *, void *);
+
+@interface PGDeviceDescriptor (IOSurfaceMapper)
+@property (readwrite, nonatomic) bool usingIOSurfaceMapper;
+@end
+
+@interface PGIOSurfaceHostDeviceDescriptor : NSObject
+-(PGIOSurfaceHostDeviceDescriptor *)init;
+@property (readwrite, nonatomic, copy, nullable) IOSFCMapMemory mapMemory;
+@property (readwrite, nonatomic, copy, nullable) IOSFCUnmapMemory unmapMemory;
+@property (readwrite, nonatomic, copy, nullable) IOSFCRaiseInterrupt raiseInterrupt;
+@end
+
+@interface PGIOSurfaceHostDevice : NSObject
+-(instancetype)initWithDescriptor:(PGIOSurfaceHostDeviceDescriptor *)desc;
+-(uint32_t)mmioReadAtOffset:(size_t)offset;
+-(void)mmioWriteAtOffset:(size_t)offset value:(uint32_t)value;
+@end
+
+struct AppleGFXMapSurfaceMemoryJob;
+struct AppleGFXMMIOState {
+    SysBusDevice parent_obj;
+
+    AppleGFXState common;
+
+    qemu_irq irq_gfx;
+    qemu_irq irq_iosfc;
+    MemoryRegion iomem_iosfc;
+    PGIOSurfaceHostDevice *pgiosfc;
+};
+
+typedef struct AppleGFXMMIOJob {
+    AppleGFXMMIOState *state;
+    uint64_t offset;
+    uint64_t value;
+    bool completed;
+} AppleGFXMMIOJob;
+
+static void iosfc_do_read(void *opaque)
+{
+    AppleGFXMMIOJob *job = opaque;
+    job->value = [job->state->pgiosfc mmioReadAtOffset:job->offset];
+    qatomic_set(&job->completed, true);
+    aio_wait_kick();
+}
+
+static uint64_t iosfc_read(void *opaque, hwaddr offset, unsigned size)
+{
+    AppleGFXMMIOJob job = {
+        .state = opaque,
+        .offset = offset,
+        .completed = false,
+    };
+    dispatch_queue_t queue =
+        dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
+
+    dispatch_async_f(queue, &job, iosfc_do_read);
+    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
+
+    trace_apple_gfx_mmio_iosfc_read(offset, job.value);
+    return job.value;
+}
+
+static void iosfc_do_write(void *opaque)
+{
+    AppleGFXMMIOJob *job = opaque;
+    [job->state->pgiosfc mmioWriteAtOffset:job->offset value:job->value];
+    qatomic_set(&job->completed, true);
+    aio_wait_kick();
+}
+
+static void iosfc_write(void *opaque, hwaddr offset, uint64_t val,
+                        unsigned size)
+{
+    AppleGFXMMIOJob job = {
+        .state = opaque,
+        .offset = offset,
+        .value = val,
+        .completed = false,
+    };
+    dispatch_queue_t queue =
+        dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
+
+    dispatch_async_f(queue, &job, iosfc_do_write);
+    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
+
+    trace_apple_gfx_mmio_iosfc_write(offset, val);
+}
+
+static const MemoryRegionOps apple_iosfc_ops = {
+    .read = iosfc_read,
+    .write = iosfc_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+};
+
+static void raise_irq_bh(void *opaque)
+{
+    qemu_irq *irq = opaque;
+
+    qemu_irq_pulse(*irq);
+}
+
+static void *apple_gfx_mmio_map_surface_memory(uint64_t guest_physical_address,
+                                               uint64_t length, bool read_only)
+{
+    mach_vm_address_t mem;
+    MemoryRegion *region = NULL;
+
+    RCU_READ_LOCK_GUARD();
+    mem = apple_gfx_host_address_for_gpa_range(guest_physical_address,
+                                               length, read_only, &region);
+
+    if (mem != 0) {
+        memory_region_ref(region);
+    }
+
+    return (void *)mem;
+}
+
+static bool apple_gfx_mmio_unmap_surface_memory(void *virtual_address)
+{
+    MemoryRegion *region;
+    ram_addr_t offset = 0;
+
+    RCU_READ_LOCK_GUARD();
+    region = memory_region_from_host(virtual_address, &offset);
+    if (!region) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: memory at %p to be unmapped not "
+                      "found.\n",
+                      __func__,
+                      virtual_address);
+        return false;
+    }
+
+    trace_apple_gfx_iosfc_unmap_memory_region(virtual_address, region);
+    memory_region_unref(region);
+    return true;
+}
+
+static PGIOSurfaceHostDevice *apple_gfx_prepare_iosurface_host_device(
+    AppleGFXMMIOState *s)
+{
+    PGIOSurfaceHostDeviceDescriptor *iosfc_desc =
+        [PGIOSurfaceHostDeviceDescriptor new];
+    PGIOSurfaceHostDevice *iosfc_host_dev = nil;
+
+    iosfc_desc.mapMemory =
+        ^bool(uint64_t phys, uint64_t len, bool ro, void **va, void *e, void *f) {
+            *va = apple_gfx_mmio_map_surface_memory(phys, len, ro);
+
+            trace_apple_gfx_iosfc_map_memory(phys, len, ro, va, e, f, *va);
+
+            return *va != NULL;
+        };
+
+    iosfc_desc.unmapMemory =
+        ^bool(void *va, void *b, void *c, void *d, void *e, void *f) {
+            return apple_gfx_mmio_unmap_surface_memory(s);
+        };
+
+    iosfc_desc.raiseInterrupt = ^bool(uint32_t vector) {
+        trace_apple_gfx_iosfc_raise_irq(vector);
+        aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                                raise_irq_bh, &s->irq_iosfc);
+        return true;
+    };
+
+    iosfc_host_dev =
+        [[PGIOSurfaceHostDevice alloc] initWithDescriptor:iosfc_desc];
+    [iosfc_desc release];
+    return iosfc_host_dev;
+}
+
+static void apple_gfx_mmio_realize(DeviceState *dev, Error **errp)
+{
+    @autoreleasepool {
+        AppleGFXMMIOState *s = APPLE_GFX_MMIO(dev);
+        PGDeviceDescriptor *desc = [PGDeviceDescriptor new];
+
+        desc.raiseInterrupt = ^(uint32_t vector) {
+            trace_apple_gfx_raise_irq(vector);
+            aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                                    raise_irq_bh, &s->irq_gfx);
+        };
+
+        desc.usingIOSurfaceMapper = true;
+        s->pgiosfc = apple_gfx_prepare_iosurface_host_device(s);
+
+        apple_gfx_common_realize(&s->common, desc, errp);
+
+        [desc release];
+        desc = nil;
+    }
+}
+
+static void apple_gfx_mmio_init(Object *obj)
+{
+    AppleGFXMMIOState *s = APPLE_GFX_MMIO(obj);
+
+    apple_gfx_common_init(obj, &s->common, TYPE_APPLE_GFX_MMIO);
+
+    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->common.iomem_gfx);
+    memory_region_init_io(&s->iomem_iosfc, obj, &apple_iosfc_ops, s,
+                          TYPE_APPLE_GFX_MMIO, 0x10000);
+    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem_iosfc);
+    sysbus_init_irq(SYS_BUS_DEVICE(s), &s->irq_gfx);
+    sysbus_init_irq(SYS_BUS_DEVICE(s), &s->irq_iosfc);
+}
+
+static void apple_gfx_mmio_reset(Object *obj, ResetType type)
+{
+    AppleGFXMMIOState *s = APPLE_GFX_MMIO(obj);
+    [s->common.pgdev reset];
+}
+
+
+static void apple_gfx_mmio_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+
+    rc->phases.hold = apple_gfx_mmio_reset;
+    dc->hotpluggable = false;
+    dc->realize = apple_gfx_mmio_realize;
+}
+
+static TypeInfo apple_gfx_mmio_types[] = {
+    {
+        .name          = TYPE_APPLE_GFX_MMIO,
+        .parent        = TYPE_SYS_BUS_DEVICE,
+        .instance_size = sizeof(AppleGFXMMIOState),
+        .class_init    = apple_gfx_mmio_class_init,
+        .instance_init = apple_gfx_mmio_init,
+    }
+};
+DEFINE_TYPES(apple_gfx_mmio_types)
diff --git a/hw/display/apple-gfx.h b/hw/display/apple-gfx.h
new file mode 100644
index 00000000000..91b55299338
--- /dev/null
+++ b/hw/display/apple-gfx.h
@@ -0,0 +1,65 @@
+/*
+ * Data structures and functions shared between variants of the macOS
+ * ParavirtualizedGraphics.framework based apple-gfx display adapter.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QEMU_APPLE_GFX_H
+#define QEMU_APPLE_GFX_H
+
+#define TYPE_APPLE_GFX_MMIO         "apple-gfx-mmio"
+#define TYPE_APPLE_GFX_PCI          "apple-gfx-pci"
+
+#include "qemu/osdep.h"
+#include <dispatch/dispatch.h>
+#import <ParavirtualizedGraphics/ParavirtualizedGraphics.h>
+#include "qemu/typedefs.h"
+#include "exec/memory.h"
+#include "ui/surface.h"
+
+@class PGDeviceDescriptor;
+@protocol PGDevice;
+@protocol PGDisplay;
+@protocol MTLDevice;
+@protocol MTLTexture;
+@protocol MTLCommandQueue;
+
+typedef QTAILQ_HEAD(, PGTask_s) PGTaskList;
+
+typedef struct AppleGFXState {
+    /* Initialised on init/realize() */
+    MemoryRegion iomem_gfx;
+    id<PGDevice> pgdev;
+    id<PGDisplay> pgdisp;
+    QemuConsole *con;
+    id<MTLDevice> mtl;
+    id<MTLCommandQueue> mtl_queue;
+    dispatch_queue_t render_queue;
+
+    /* List `tasks` is protected by task_mutex */
+    QemuMutex task_mutex;
+    PGTaskList tasks;
+
+    /* Mutable state (BQL protected) */
+    QEMUCursor *cursor;
+    DisplaySurface *surface;
+    id<MTLTexture> texture;
+    int32_t pending_frames; /* # guest frames in the rendering pipeline */
+    bool gfx_update_requested; /* QEMU display system wants a new frame */
+    bool new_frame_ready; /* Guest has rendered a frame, ready to be used */
+    bool using_managed_texture_storage;
+
+    /* Mutable state (atomic) */
+    bool cursor_show;
+} AppleGFXState;
+
+void apple_gfx_common_init(Object *obj, AppleGFXState *s, const char* obj_name);
+void apple_gfx_common_realize(AppleGFXState *s, PGDeviceDescriptor *desc,
+                              Error **errp);
+uintptr_t apple_gfx_host_address_for_gpa_range(uint64_t guest_physical,
+                                               uint64_t length, bool read_only,
+                                               MemoryRegion **mapping_in_region);
+
+#endif
+
diff --git a/hw/display/apple-gfx.m b/hw/display/apple-gfx.m
new file mode 100644
index 00000000000..b0428648394
--- /dev/null
+++ b/hw/display/apple-gfx.m
@@ -0,0 +1,770 @@
+/*
+ * QEMU Apple ParavirtualizedGraphics.framework device
+ *
+ * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * ParavirtualizedGraphics.framework is a set of libraries that macOS provides
+ * which implements 3d graphics passthrough to the host as well as a
+ * proprietary guest communication channel to drive it. This device model
+ * implements support to drive that library from within QEMU.
+ */
+
+#include "qemu/osdep.h"
+#import <ParavirtualizedGraphics/ParavirtualizedGraphics.h>
+#include <mach/mach_vm.h>
+#include "apple-gfx.h"
+#include "trace.h"
+#include "qemu-main.h"
+#include "exec/address-spaces.h"
+#include "migration/blocker.h"
+#include "monitor/monitor.h"
+#include "qemu/main-loop.h"
+#include "qemu/cutils.h"
+#include "qemu/log.h"
+#include "qapi/visitor.h"
+#include "qapi/error.h"
+#include "sysemu/dma.h"
+#include "ui/console.h"
+
+static const PGDisplayCoord_t apple_gfx_modes[] = {
+    { .x = 1440, .y = 1080 },
+    { .x = 1280, .y = 1024 },
+};
+
+/* ------ PGTask and task operations: new/destroy/map/unmap ------ */
+
+/*
+ * This implements the type declared in <ParavirtualizedGraphics/PGDevice.h>
+ * which is opaque from the framework's point of view. It is used in callbacks
+ * in the form of its typedef PGTask_t, which also already exists in the
+ * framework headers.
+ *
+ * A "task" in PVG terminology represents a host-virtual contiguous address
+ * range which is reserved in a large chunk on task creation. The mapMemory
+ * callback then requests ranges of guest system memory (identified by their
+ * GPA) to be mapped into subranges of this reserved address space.
+ * This type of operation isn't well-supported by QEMU's memory subsystem,
+ * but it is fortunately trivial to achieve with Darwin's mach_vm_remap() call,
+ * which allows us to refer to the same backing memory via multiple virtual
+ * address ranges. The Mach VM APIs are therefore used throughout for managing
+ * task memory.
+ */
+struct PGTask_s {
+    QTAILQ_ENTRY(PGTask_s) node;
+    AppleGFXState *s;
+    mach_vm_address_t address;
+    uint64_t len;
+    /*
+     * All unique MemoryRegions for which a mapping has been created in in this
+     * task, and on which we have thus called memory_region_ref(). There are
+     * usually very few regions of system RAM in total, so we expect this array
+     * to be very short. Therefore, no need for sorting or fancy search
+     * algorithms, linear search will do.
+     * Protected by AppleGFXState's task_mutex.
+     */
+    GPtrArray *mapped_regions;
+};
+
+static Error *apple_gfx_mig_blocker;
+
+static PGTask_t *apple_gfx_new_task(AppleGFXState *s, uint64_t len)
+{
+    mach_vm_address_t task_mem;
+    PGTask_t *task;
+    kern_return_t r;
+
+    r = mach_vm_allocate(mach_task_self(), &task_mem, len, VM_FLAGS_ANYWHERE);
+    if (r != KERN_SUCCESS) {
+        return NULL;
+    }
+
+    task = g_new0(PGTask_t, 1);
+    task->s = s;
+    task->address = task_mem;
+    task->len = len;
+    task->mapped_regions = g_ptr_array_sized_new(2 /* Usually enough */);
+
+    QEMU_LOCK_GUARD(&s->task_mutex);
+    QTAILQ_INSERT_TAIL(&s->tasks, task, node);
+
+    return task;
+}
+
+static void apple_gfx_destroy_task(AppleGFXState *s, PGTask_t *task)
+{
+    GPtrArray *regions = task->mapped_regions;
+    MemoryRegion *region;
+    size_t i;
+
+    for (i = 0; i < regions->len; ++i) {
+        region = g_ptr_array_index(regions, i);
+        memory_region_unref(region);
+    }
+    g_ptr_array_unref(regions);
+
+    mach_vm_deallocate(mach_task_self(), task->address, task->len);
+
+    QEMU_LOCK_GUARD(&s->task_mutex);
+    QTAILQ_REMOVE(&s->tasks, task, node);
+    g_free(task);
+}
+
+uintptr_t apple_gfx_host_address_for_gpa_range(uint64_t guest_physical,
+                                               uint64_t length, bool read_only,
+                                               MemoryRegion **mapping_in_region)
+{
+    MemoryRegion *ram_region;
+    uintptr_t host_address;
+    hwaddr ram_region_offset = 0;
+    hwaddr ram_region_length = length;
+
+    ram_region = address_space_translate(&address_space_memory,
+                                         guest_physical,
+                                         &ram_region_offset,
+                                         &ram_region_length, !read_only,
+                                         MEMTXATTRS_UNSPECIFIED);
+
+    if (!ram_region || ram_region_length < length ||
+        !memory_access_is_direct(ram_region, !read_only)) {
+        return 0;
+    }
+
+    host_address = (uintptr_t)memory_region_get_ram_ptr(ram_region);
+    if (host_address == 0) {
+        return 0;
+    }
+    host_address += ram_region_offset;
+    *mapping_in_region = ram_region;
+    return host_address;
+}
+
+/* Returns false if the region is already in the array */
+static bool add_new_region(GPtrArray *regions, MemoryRegion *region)
+{
+    guint found_index;
+
+    if (g_ptr_array_find(regions, region, &found_index)) {
+        return false;
+    }
+
+    g_ptr_array_add(regions, region);
+    return true;
+}
+
+static bool apple_gfx_task_map_memory(AppleGFXState *s, PGTask_t *task,
+                                      uint64_t virtual_offset,
+                                      PGPhysicalMemoryRange_t *ranges,
+                                      uint32_t range_count, bool read_only)
+{
+    kern_return_t r;
+    mach_vm_address_t target, source;
+    vm_prot_t cur_protection, max_protection;
+    bool success = true;
+    MemoryRegion *region;
+
+    RCU_READ_LOCK_GUARD();
+    QEMU_LOCK_GUARD(&s->task_mutex);
+
+    trace_apple_gfx_map_memory(task, range_count, virtual_offset, read_only);
+    for (int i = 0; i < range_count; i++) {
+        PGPhysicalMemoryRange_t *range = &ranges[i];
+
+        target = task->address + virtual_offset;
+        virtual_offset += range->physicalLength;
+
+        trace_apple_gfx_map_memory_range(i, range->physicalAddress,
+                                         range->physicalLength);
+
+        region = NULL;
+        source = apple_gfx_host_address_for_gpa_range(range->physicalAddress,
+                                                      range->physicalLength,
+                                                      read_only, &region);
+        if (source == 0) {
+            success = false;
+            continue;
+        }
+
+        if (add_new_region(task->mapped_regions, region)) {
+            memory_region_ref(region);
+        }
+
+        cur_protection = 0;
+        max_protection = 0;
+        // Map guest RAM at range->physicalAddress into PG task memory range
+        r = mach_vm_remap(mach_task_self(),
+                          &target, range->physicalLength, vm_page_size - 1,
+                          VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE,
+                          mach_task_self(),
+                          source, false /* shared mapping, no copy */,
+                          &cur_protection, &max_protection,
+                          VM_INHERIT_COPY);
+        trace_apple_gfx_remap(r, source, target);
+        g_assert(r == KERN_SUCCESS);
+    }
+
+    return success;
+}
+
+static void apple_gfx_task_unmap_memory(AppleGFXState *s, PGTask_t *task,
+                                        uint64_t virtual_offset, uint64_t length)
+{
+    kern_return_t r;
+    mach_vm_address_t range_address;
+
+    trace_apple_gfx_unmap_memory(task, virtual_offset, length);
+
+    /*
+     * Replace task memory range with fresh 0 pages, undoing the mapping
+     * from guest RAM.
+     */
+    range_address = task->address + virtual_offset;
+    r = mach_vm_allocate(mach_task_self(), &range_address, length,
+                         VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE);
+    g_assert(r == KERN_SUCCESS);
+}
+
+/* ------ Rendering and frame management ------ */
+
+static void apple_gfx_render_frame_completed(AppleGFXState *s,
+                                             uint32_t width, uint32_t height);
+
+static void apple_gfx_render_new_frame_bql_unlock(AppleGFXState *s)
+{
+    BOOL r;
+    bool managed_texture = s->using_managed_texture_storage;
+    uint32_t width = surface_width(s->surface);
+    uint32_t height = surface_height(s->surface);
+    MTLRegion region = MTLRegionMake2D(0, 0, width, height);
+    id<MTLCommandBuffer> command_buffer = [s->mtl_queue commandBuffer];
+    id<MTLTexture> texture = s->texture;
+
+    assert(bql_locked());
+    [texture retain];
+
+    bql_unlock();
+
+    /* This is not safe to call from the BQL due to PVG-internal locks causing
+     * deadlocks. */
+    r = [s->pgdisp encodeCurrentFrameToCommandBuffer:command_buffer
+                                             texture:texture
+                                              region:region];
+    if (!r) {
+        [texture release];
+        bql_lock();
+        --s->pending_frames;
+        bql_unlock();
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: encodeCurrentFrameToCommandBuffer:texture:region: "
+                      "failed\n", __func__);
+        return;
+    }
+
+    if (managed_texture) {
+        /* "Managed" textures exist in both VRAM and RAM and must be synced. */
+        id<MTLBlitCommandEncoder> blit = [command_buffer blitCommandEncoder];
+        [blit synchronizeResource:texture];
+        [blit endEncoding];
+    }
+    [texture release];
+    [command_buffer addCompletedHandler:
+        ^(id<MTLCommandBuffer> cb)
+        {
+            dispatch_async(s->render_queue, ^{
+                apple_gfx_render_frame_completed(s, width, height);
+            });
+        }];
+    [command_buffer commit];
+}
+
+static void copy_mtl_texture_to_surface_mem(id<MTLTexture> texture, void *vram)
+{
+    /* TODO: Skip this entirely on a pure Metal or headless/guest-only
+     * rendering path, else use a blit command encoder? Needs careful
+     * (double?) buffering design. */
+    size_t width = texture.width, height = texture.height;
+    MTLRegion region = MTLRegionMake2D(0, 0, width, height);
+    [texture getBytes:vram
+          bytesPerRow:(width * 4)
+        bytesPerImage:(width * height * 4)
+           fromRegion:region
+          mipmapLevel:0
+                slice:0];
+}
+
+static void apple_gfx_render_frame_completed(AppleGFXState *s,
+                                             uint32_t width, uint32_t height)
+{
+    bql_lock();
+    --s->pending_frames;
+    assert(s->pending_frames >= 0);
+
+    /* Only update display if mode hasn't changed since we started rendering. */
+    if (width == surface_width(s->surface) &&
+        height == surface_height(s->surface)) {
+        copy_mtl_texture_to_surface_mem(s->texture, surface_data(s->surface));
+        if (s->gfx_update_requested) {
+            s->gfx_update_requested = false;
+            dpy_gfx_update_full(s->con);
+            graphic_hw_update_done(s->con);
+            s->new_frame_ready = false;
+        } else {
+            s->new_frame_ready = true;
+        }
+    }
+    if (s->pending_frames > 0) {
+        apple_gfx_render_new_frame_bql_unlock(s);
+    } else {
+        bql_unlock();
+    }
+}
+
+static void apple_gfx_fb_update_display(void *opaque)
+{
+    AppleGFXState *s = opaque;
+
+    assert(bql_locked());
+    if (s->new_frame_ready) {
+        dpy_gfx_update_full(s->con);
+        s->new_frame_ready = false;
+        graphic_hw_update_done(s->con);
+    } else if (s->pending_frames > 0) {
+        s->gfx_update_requested = true;
+    } else {
+        graphic_hw_update_done(s->con);
+    }
+}
+
+static const GraphicHwOps apple_gfx_fb_ops = {
+    .gfx_update = apple_gfx_fb_update_display,
+    .gfx_update_async = true,
+};
+
+/* ------ Mouse cursor and display mode setting ------ */
+
+static void set_mode(AppleGFXState *s, uint32_t width, uint32_t height)
+{
+    MTLTextureDescriptor *textureDescriptor;
+
+    if (s->surface &&
+        width == surface_width(s->surface) &&
+        height == surface_height(s->surface)) {
+        return;
+    }
+
+    [s->texture release];
+
+    s->surface = qemu_create_displaysurface(width, height);
+
+    @autoreleasepool {
+        textureDescriptor =
+            [MTLTextureDescriptor
+                texture2DDescriptorWithPixelFormat:MTLPixelFormatBGRA8Unorm
+                                             width:width
+                                            height:height
+                                         mipmapped:NO];
+        textureDescriptor.usage = s->pgdisp.minimumTextureUsage;
+        s->texture = [s->mtl newTextureWithDescriptor:textureDescriptor];
+    }
+
+    s->using_managed_texture_storage =
+        (s->texture.storageMode == MTLStorageModeManaged);
+    dpy_gfx_replace_surface(s->con, s->surface);
+}
+
+static void update_cursor(AppleGFXState *s)
+{
+    assert(bql_locked());
+    dpy_mouse_set(s->con, s->pgdisp.cursorPosition.x,
+                  s->pgdisp.cursorPosition.y, qatomic_read(&s->cursor_show));
+}
+
+static void update_cursor_bh(void *opaque)
+{
+    AppleGFXState *s = opaque;
+    update_cursor(s);
+}
+
+typedef struct AppleGFXSetCursorGlyphJob {
+    AppleGFXState *s;
+    NSBitmapImageRep *glyph;
+    PGDisplayCoord_t hotspot;
+} AppleGFXSetCursorGlyphJob;
+
+static void set_cursor_glyph(void *opaque)
+{
+    AppleGFXSetCursorGlyphJob *job = opaque;
+    AppleGFXState *s = job->s;
+    NSBitmapImageRep *glyph = job->glyph;
+    uint32_t bpp = glyph.bitsPerPixel;
+    size_t width = glyph.pixelsWide;
+    size_t height = glyph.pixelsHigh;
+    size_t padding_bytes_per_row = glyph.bytesPerRow - width * 4;
+    const uint8_t* px_data = glyph.bitmapData;
+
+    trace_apple_gfx_cursor_set(bpp, width, height);
+
+    if (s->cursor) {
+        cursor_unref(s->cursor);
+        s->cursor = NULL;
+    }
+
+    if (bpp == 32) { /* Shouldn't be anything else, but just to be safe...*/
+        s->cursor = cursor_alloc(width, height);
+        s->cursor->hot_x = job->hotspot.x;
+        s->cursor->hot_y = job->hotspot.y;
+
+        uint32_t *dest_px = s->cursor->data;
+
+        for (size_t y = 0; y < height; ++y) {
+            for (size_t x = 0; x < width; ++x) {
+                /* NSBitmapImageRep's red & blue channels are swapped
+                 * compared to QEMUCursor's. */
+                *dest_px =
+                    (px_data[0] << 16u) |
+                    (px_data[1] <<  8u) |
+                    (px_data[2] <<  0u) |
+                    (px_data[3] << 24u);
+                ++dest_px;
+                px_data += 4;
+            }
+            px_data += padding_bytes_per_row;
+        }
+        dpy_cursor_define(s->con, s->cursor);
+        update_cursor(s);
+    }
+    [glyph release];
+
+    g_free(job);
+}
+
+/* ------ DMA (device reading system memory) ------ */
+
+typedef struct AppleGFXReadMemoryJob {
+    QemuSemaphore sem;
+    hwaddr physical_address;
+    uint64_t length;
+    void *dst;
+    bool success;
+} AppleGFXReadMemoryJob;
+
+static void apple_gfx_do_read_memory(void *opaque)
+{
+    AppleGFXReadMemoryJob *job = opaque;
+    MemTxResult r;
+
+    r = dma_memory_read(&address_space_memory, job->physical_address,
+                        job->dst, job->length, MEMTXATTRS_UNSPECIFIED);
+    job->success = r == MEMTX_OK;
+
+    qemu_sem_post(&job->sem);
+}
+
+static bool apple_gfx_read_memory(AppleGFXState *s, hwaddr physical_address,
+                                  uint64_t length, void *dst)
+{
+    AppleGFXReadMemoryJob job = {
+        .physical_address = physical_address, .length = length, .dst = dst
+    };
+
+    trace_apple_gfx_read_memory(physical_address, length, dst);
+
+    /* Performing DMA requires BQL, so do it in a BH. */
+    qemu_sem_init(&job.sem, 0);
+    aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                            apple_gfx_do_read_memory, &job);
+    qemu_sem_wait(&job.sem);
+    qemu_sem_destroy(&job.sem);
+    return job.success;
+}
+
+/* ------ Memory-mapped device I/O operations ------ */
+
+static dispatch_queue_t get_background_queue(void)
+{
+    return dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
+}
+
+typedef struct AppleGFXIOJob {
+    AppleGFXState *state;
+    uint64_t offset;
+    uint64_t value;
+    bool completed;
+} AppleGFXIOJob;
+
+static void apple_gfx_do_read(void *opaque)
+{
+    AppleGFXIOJob *job = opaque;
+    job->value = [job->state->pgdev mmioReadAtOffset:job->offset];
+    qatomic_set(&job->completed, true);
+    aio_wait_kick();
+}
+
+static uint64_t apple_gfx_read(void *opaque, hwaddr offset, unsigned size)
+{
+    AppleGFXIOJob job = {
+        .state = opaque,
+        .offset = offset,
+        .completed = false,
+    };
+    dispatch_queue_t queue = get_background_queue();
+
+    dispatch_async_f(queue, &job, apple_gfx_do_read);
+    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
+
+    trace_apple_gfx_read(offset, job.value);
+    return job.value;
+}
+
+static void apple_gfx_do_write(void *opaque)
+{
+    AppleGFXIOJob *job = opaque;
+    [job->state->pgdev mmioWriteAtOffset:job->offset value:job->value];
+    qatomic_set(&job->completed, true);
+    aio_wait_kick();
+}
+
+static void apple_gfx_write(void *opaque, hwaddr offset, uint64_t val,
+                            unsigned size)
+{
+    /*
+     * The methods mmioReadAtOffset: and especially mmioWriteAtOffset: can
+     * trigger synchronous operations on other dispatch queues, which in turn
+     * may call back out on one or more of the callback blocks. For this reason,
+     * and as we are holding the BQL, we invoke the I/O methods on a pool
+     * thread and handle AIO tasks while we wait. Any work in the callbacks
+     * requiring the BQL will in turn schedule BHs which this thread will
+     * process while waiting.
+     */
+    AppleGFXIOJob job = {
+        .state = opaque,
+        .offset = offset,
+        .value = val,
+        .completed = false,
+    };
+    dispatch_queue_t queue = get_background_queue();
+
+    dispatch_async_f(queue, &job, apple_gfx_do_write);
+    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
+
+    trace_apple_gfx_write(offset, val);
+}
+
+static const MemoryRegionOps apple_gfx_ops = {
+    .read = apple_gfx_read,
+    .write = apple_gfx_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    },
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+};
+
+static size_t apple_gfx_get_default_mmio_range_size(void)
+{
+    size_t mmio_range_size;
+    @autoreleasepool {
+        PGDeviceDescriptor *desc = [PGDeviceDescriptor new];
+        mmio_range_size = desc.mmioLength;
+        [desc release];
+    }
+    return mmio_range_size;
+}
+
+/* ------ Initialisation and startup ------ */
+
+void apple_gfx_common_init(Object *obj, AppleGFXState *s, const char* obj_name)
+{
+    size_t mmio_range_size = apple_gfx_get_default_mmio_range_size();
+
+    trace_apple_gfx_common_init(obj_name, mmio_range_size);
+    memory_region_init_io(&s->iomem_gfx, obj, &apple_gfx_ops, s, obj_name,
+                          mmio_range_size);
+
+    /* TODO: PVG framework supports serialising device state: integrate it! */
+}
+
+static void apple_gfx_register_task_mapping_handlers(AppleGFXState *s,
+                                                     PGDeviceDescriptor *desc)
+{
+    desc.createTask = ^(uint64_t vmSize, void * _Nullable * _Nonnull baseAddress) {
+        PGTask_t *task = apple_gfx_new_task(s, vmSize);
+        *baseAddress = (void *)task->address;
+        trace_apple_gfx_create_task(vmSize, *baseAddress);
+        return task;
+    };
+
+    desc.destroyTask = ^(PGTask_t * _Nonnull task) {
+        trace_apple_gfx_destroy_task(task, task->mapped_regions->len);
+
+        apple_gfx_destroy_task(s, task);
+    };
+
+    desc.mapMemory = ^bool(PGTask_t * _Nonnull task, uint32_t range_count,
+                           uint64_t virtual_offset, bool read_only,
+                           PGPhysicalMemoryRange_t * _Nonnull ranges) {
+        return apple_gfx_task_map_memory(s, task, virtual_offset,
+                                         ranges, range_count, read_only);
+    };
+
+    desc.unmapMemory = ^bool(PGTask_t * _Nonnull task, uint64_t virtual_offset,
+                             uint64_t length) {
+        apple_gfx_task_unmap_memory(s, task, virtual_offset, length);
+        return true;
+    };
+
+    desc.readMemory = ^bool(uint64_t physical_address, uint64_t length,
+                            void * _Nonnull dst) {
+        return apple_gfx_read_memory(s, physical_address, length, dst);
+    };
+}
+
+static PGDisplayDescriptor *apple_gfx_prepare_display_descriptor(AppleGFXState *s)
+{
+    PGDisplayDescriptor *disp_desc = [PGDisplayDescriptor new];
+
+    disp_desc.name = @"QEMU display";
+    disp_desc.sizeInMillimeters = NSMakeSize(400., 300.); /* A 20" display */
+    disp_desc.queue = dispatch_get_main_queue();
+    disp_desc.newFrameEventHandler = ^(void) {
+        trace_apple_gfx_new_frame();
+        dispatch_async(s->render_queue, ^{
+            /* Drop frames if we get too far ahead. */
+            bql_lock();
+            if (s->pending_frames >= 2) {
+                bql_unlock();
+                return;
+            }
+            ++s->pending_frames;
+            if (s->pending_frames > 1) {
+                bql_unlock();
+                return;
+            }
+            @autoreleasepool {
+                apple_gfx_render_new_frame_bql_unlock(s);
+            }
+        });
+    };
+    disp_desc.modeChangeHandler = ^(PGDisplayCoord_t sizeInPixels,
+                                    OSType pixelFormat) {
+        trace_apple_gfx_mode_change(sizeInPixels.x, sizeInPixels.y);
+
+        BQL_LOCK_GUARD();
+        set_mode(s, sizeInPixels.x, sizeInPixels.y);
+    };
+    disp_desc.cursorGlyphHandler = ^(NSBitmapImageRep *glyph,
+                                     PGDisplayCoord_t hotspot) {
+        AppleGFXSetCursorGlyphJob *job = g_malloc0(sizeof(*job));
+        job->s = s;
+        job->glyph = glyph;
+        job->hotspot = hotspot;
+        [glyph retain];
+        aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                                set_cursor_glyph, job);
+    };
+    disp_desc.cursorShowHandler = ^(BOOL show) {
+        trace_apple_gfx_cursor_show(show);
+        qatomic_set(&s->cursor_show, show);
+        aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                                update_cursor_bh, s);
+    };
+    disp_desc.cursorMoveHandler = ^(void) {
+        trace_apple_gfx_cursor_move();
+        aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                                update_cursor_bh, s);
+    };
+
+    return disp_desc;
+}
+
+static NSArray<PGDisplayMode*>* apple_gfx_prepare_display_mode_array(void)
+{
+    PGDisplayMode *modes[ARRAY_SIZE(apple_gfx_modes)];
+    NSArray<PGDisplayMode*>* mode_array = nil;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(apple_gfx_modes); i++) {
+        modes[i] =
+            [[PGDisplayMode alloc] initWithSizeInPixels:apple_gfx_modes[i] refreshRateInHz:60.];
+    }
+
+    mode_array = [NSArray arrayWithObjects:modes count:ARRAY_SIZE(apple_gfx_modes)];
+
+    for (i = 0; i < ARRAY_SIZE(apple_gfx_modes); i++) {
+        [modes[i] release];
+        modes[i] = nil;
+    }
+
+    return mode_array;
+}
+
+static id<MTLDevice> copy_suitable_metal_device(void)
+{
+    id<MTLDevice> dev = nil;
+    NSArray<id<MTLDevice>> *devs = MTLCopyAllDevices();
+
+    /* Prefer a unified memory GPU. Failing that, pick a non-removable GPU. */
+    for (size_t i = 0; i < devs.count; ++i) {
+        if (devs[i].hasUnifiedMemory) {
+            dev = devs[i];
+            break;
+        }
+        if (!devs[i].removable) {
+            dev = devs[i];
+        }
+    }
+
+    if (dev != nil) {
+        [dev retain];
+    } else {
+        dev = MTLCreateSystemDefaultDevice();
+    }
+    [devs release];
+
+    return dev;
+}
+
+void apple_gfx_common_realize(AppleGFXState *s, PGDeviceDescriptor *desc,
+                              Error **errp)
+{
+    PGDisplayDescriptor *disp_desc = nil;
+
+    if (apple_gfx_mig_blocker == NULL) {
+        error_setg(&apple_gfx_mig_blocker,
+                  "Migration state blocked by apple-gfx display device");
+        if (migrate_add_blocker(&apple_gfx_mig_blocker, errp) < 0) {
+            return;
+        }
+    }
+
+    qemu_mutex_init(&s->task_mutex);
+    QTAILQ_INIT(&s->tasks);
+    s->render_queue = dispatch_queue_create("apple-gfx.render",
+                                            DISPATCH_QUEUE_SERIAL);
+    s->mtl = copy_suitable_metal_device();
+    s->mtl_queue = [s->mtl newCommandQueue];
+
+    desc.device = s->mtl;
+
+    apple_gfx_register_task_mapping_handlers(s, desc);
+
+    s->pgdev = PGNewDeviceWithDescriptor(desc);
+
+    disp_desc = apple_gfx_prepare_display_descriptor(s);
+    s->pgdisp = [s->pgdev newDisplayWithDescriptor:disp_desc
+                                              port:0 serialNum:1234];
+    [disp_desc release];
+    s->pgdisp.modeList = apple_gfx_prepare_display_mode_array();
+
+    s->con = graphic_console_init(NULL, 0, &apple_gfx_fb_ops, s);
+
+    qatomic_set(&s->cursor_show, true);
+}
diff --git a/hw/display/meson.build b/hw/display/meson.build
index 20a94973fa2..619e642905a 100644
--- a/hw/display/meson.build
+++ b/hw/display/meson.build
@@ -61,6 +61,10 @@ system_ss.add(when: 'CONFIG_ARTIST', if_true: files('artist.c'))
 
 system_ss.add(when: 'CONFIG_ATI_VGA', if_true: [files('ati.c', 'ati_2d.c', 'ati_dbg.c'), pixman])
 
+system_ss.add(when: 'CONFIG_MAC_PVG',         if_true: [files('apple-gfx.m'), pvg, metal])
+if cpu == 'aarch64'
+  system_ss.add(when: 'CONFIG_MAC_PVG_MMIO',  if_true: [files('apple-gfx-mmio.m'), pvg, metal])
+endif
 
 if config_all_devices.has_key('CONFIG_VIRTIO_GPU')
   virtio_gpu_ss = ss.source_set()
diff --git a/hw/display/trace-events b/hw/display/trace-events
index d26d663f963..260eab9146d 100644
--- a/hw/display/trace-events
+++ b/hw/display/trace-events
@@ -194,3 +194,31 @@ dm163_bits_ppi(unsigned dest_width) "dest_width : %u"
 dm163_leds(int led, uint32_t value) "led %d: 0x%x"
 dm163_channels(int channel, uint8_t value) "channel %d: 0x%x"
 dm163_refresh_rate(uint32_t rr) "refresh rate %d"
+
+# apple-gfx.m
+apple_gfx_read(uint64_t offset, uint64_t res) "offset=0x%"PRIx64" res=0x%"PRIx64
+apple_gfx_write(uint64_t offset, uint64_t val) "offset=0x%"PRIx64" val=0x%"PRIx64
+apple_gfx_create_task(uint32_t vm_size, void *va) "vm_size=0x%x base_addr=%p"
+apple_gfx_destroy_task(void *task, unsigned int num_mapped_regions) "task=%p, task->mapped_regions->len=%u"
+apple_gfx_map_memory(void *task, uint32_t range_count, uint64_t virtual_offset, uint32_t read_only) "task=%p range_count=0x%x virtual_offset=0x%"PRIx64" read_only=%d"
+apple_gfx_map_memory_range(uint32_t i, uint64_t phys_addr, uint64_t phys_len) "[%d] phys_addr=0x%"PRIx64" phys_len=0x%"PRIx64
+apple_gfx_remap(uint64_t retval, uint64_t source, uint64_t target) "retval=%"PRId64" source=0x%"PRIx64" target=0x%"PRIx64
+apple_gfx_unmap_memory(void *task, uint64_t virtual_offset, uint64_t length) "task=%p virtual_offset=0x%"PRIx64" length=0x%"PRIx64
+apple_gfx_read_memory(uint64_t phys_address, uint64_t length, void *dst) "phys_addr=0x%"PRIx64" length=0x%"PRIx64" dest=%p"
+apple_gfx_raise_irq(uint32_t vector) "vector=0x%x"
+apple_gfx_new_frame(void) ""
+apple_gfx_mode_change(uint64_t x, uint64_t y) "x=%"PRId64" y=%"PRId64
+apple_gfx_cursor_set(uint32_t bpp, uint64_t width, uint64_t height) "bpp=%d width=%"PRId64" height=0x%"PRId64
+apple_gfx_cursor_show(uint32_t show) "show=%d"
+apple_gfx_cursor_move(void) ""
+apple_gfx_common_init(const char *device_name, size_t mmio_size) "device: %s; MMIO size: %zu bytes"
+
+# apple-gfx-mmio.m
+apple_gfx_mmio_iosfc_read(uint64_t offset, uint64_t res) "offset=0x%"PRIx64" res=0x%"PRIx64
+apple_gfx_mmio_iosfc_write(uint64_t offset, uint64_t val) "offset=0x%"PRIx64" val=0x%"PRIx64
+apple_gfx_iosfc_map_memory(uint64_t phys, uint64_t len, uint32_t ro, void *va, void *e, void *f, void* va_result) "phys=0x%"PRIx64" len=0x%"PRIx64" ro=%d va=%p e=%p f=%p -> *va=%p"
+apple_gfx_iosfc_map_memory_new_region(size_t i, void *region, uint64_t start, uint64_t end) "index=%zu, region=%p, 0x%"PRIx64"-0x%"PRIx64
+apple_gfx_iosfc_unmap_memory(void *a, void *b, void *c, void *d, void *e, void *f) "a=%p b=%p c=%p d=%p e=%p f=%p"
+apple_gfx_iosfc_unmap_memory_region(void* mem, void *region) "unmapping @ %p from memory region %p"
+apple_gfx_iosfc_raise_irq(uint32_t vector) "vector=0x%x"
+
diff --git a/meson.build b/meson.build
index c386593c527..b1770ee39ff 100644
--- a/meson.build
+++ b/meson.build
@@ -769,6 +769,8 @@ socket = []
 version_res = []
 coref = []
 iokit = []
+pvg = []
+metal = []
 emulator_link_args = []
 midl = not_found
 widl = not_found
@@ -790,6 +792,8 @@ elif host_os == 'darwin'
   coref = dependency('appleframeworks', modules: 'CoreFoundation')
   iokit = dependency('appleframeworks', modules: 'IOKit', required: false)
   host_dsosuf = '.dylib'
+  pvg = dependency('appleframeworks', modules: 'ParavirtualizedGraphics')
+  metal = dependency('appleframeworks', modules: 'Metal')
 elif host_os == 'sunos'
   socket = [cc.find_library('socket'),
             cc.find_library('nsl'),
-- 
2.39.3 (Apple Git-145)


Re: [PATCH v7 02/15] hw/display/apple-gfx: Introduce ParavirtualizedGraphics.Framework support
Posted by Akihiko Odaki 2 weeks, 3 days ago
On 2024/11/06 0:30, Phil Dennis-Jordan wrote:
> MacOS provides a framework (library) that allows any vmm to implement a
> paravirtualized 3d graphics passthrough to the host metal stack called
> ParavirtualizedGraphics.Framework (PVG). The library abstracts away
> almost every aspect of the paravirtualized device model and only provides
> and receives callbacks on MMIO access as well as to share memory address
> space between the VM and PVG.
> 
> This patch implements a QEMU device that drives PVG for the VMApple
> variant of it.
> 
> Signed-off-by: Alexander Graf <graf@amazon.com>
> Co-authored-by: Alexander Graf <graf@amazon.com>
> 
> Subsequent changes:
> 
>   * Cherry-pick/rebase conflict fixes, API use updates.
>   * Moved from hw/vmapple/ (useful outside that machine type)
>   * Overhaul of threading model, many thread safety improvements.
>   * Asynchronous rendering.
>   * Memory and object lifetime fixes.
>   * Refactoring to split generic and (vmapple) MMIO variant specific
>     code.
> 
> Implementation wise, most of the complexity lies in the differing threading
> models of ParavirtualizedGraphics.framework, which uses libdispatch and
> internal locks, versus QEMU, which heavily uses the BQL, especially during
> memory-mapped device I/O. Great care has therefore been taken to prevent
> deadlocks by never calling into PVG methods while holding the BQL, and
> similarly never acquiring the BQL in a callback from PVG. Different strategies
> have been used (libdispatch, blocking and non-blocking BHs, RCU, etc.)
> depending on the specific requirements at each framework entry and exit point.
> 
> Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
> ---
> 
> v2:
> 
>   * Cherry-pick/rebase conflict fixes
>   * BQL function renaming
>   * Moved from hw/vmapple/ (useful outside that machine type)
>   * Code review comments: Switched to DEFINE_TYPES macro & little endian
>     MMIO.
>   * Removed some dead/superfluous code
>   * Mad set_mode thread & memory safe
>   * Added migration blocker due to lack of (de-)serialisation.
>   * Fixes to ObjC refcounting and autorelease pool usage.
>   * Fixed ObjC new/init misuse
>   * Switched to ObjC category extension for private property.
>   * Simplified task memory mapping and made it thread safe.
>   * Refactoring to split generic and vmapple MMIO variant specific
>     code.
>   * Switched to asynchronous MMIO writes on x86-64
>   * Rendering and graphics update are now done asynchronously
>   * Fixed cursor handling
>   * Coding convention fixes
>   * Removed software cursor compositing
> 
> v3:
> 
>   * Rebased on latest upstream, fixed breakages including switching to Resettable methods.
>   * Squashed patches dealing with dGPUs, MMIO area size, and GPU picking.
>   * Allow re-entrant MMIO; this simplifies the code and solves the divergence
>     between x86-64 and arm64 variants.
> 
> v4:
> 
>   * Renamed '-vmapple' device variant to '-mmio'
>   * MMIO device type now requires aarch64 host and guest
>   * Complete overhaul of the glue code for making Qemu's and
>     ParavirtualizedGraphics.framework's threading and synchronisation models
>     work together. Calls into PVG are from dispatch queues while the
>     BQL-holding initiating thread processes AIO context events; callbacks from
>     PVG are scheduled as BHs on the BQL/main AIO context, awaiting completion
>     where necessary.
>   * Guest frame rendering state is covered by the BQL, with only the PVG calls
>     outside the lock, and serialised on the named render_queue.
>   * Simplified logic for dropping frames in-flight during mode changes, fixed
>     bug in pending frames logic.
>   * Addressed smaller code review notes such as: function naming, object type
>     declarations, type names/declarations/casts, code formatting, #include
>     order, over-cautious ObjC retain/release, what goes in init vs realize,
>     etc.
> 
> v5:
> 
>   * Smaller non-functional fixes in response to review comments, such as using
>     NULL for the AIO_WAIT_WHILE context argument, type name formatting,
>     deleting leftover debug code, logging improvements, state struct field
>     order and documentation improvements, etc.
>   * Instead of a single condition variable for all synchronous BH job types,
>     there is now one for each callback block. This reduces the number
>     of threads being awoken unnecessarily to near zero.
>   * MMIO device variant: Unified the BH job for raising interrupts.
>   * Use DMA APIs for PVG framework's guest memory read requests.
>   * Thread safety improvements: ensure mutable AppleGFXState fields are not
>     accessed outside the appropriate lock. Added dedicated mutex for the task
>     list.
>   * Retain references to MemoryRegions for which there exist mappings in each
>     PGTask, and for IOSurface mappings.
> 
> v6:
> 
>   * Switched PGTask_s's' mapped_regions from GPtrArray to GArray
>   * Allow DisplaySurface to manage its own vram now that texture -> vram copy
>     occurs under BQL.
>   * Memory mapping operations now use RCU_READ_LOCK_GUARD() where possible
>     instead of a heavy-weight BH job to acquire the BQL.
>   * Changed PVG cursor and mode setting callbacks to kick off BHs instead of
>     libdispatch tasks which then locked the BQL explicitly.
>   * The single remaining callback which must wait for a BH to complete now
>     creates an ephemeral QemuSemaphore to await completion.
>   * Re-removed tracking of mapped surface manager memory regions. Just look up
>     and ref/unref the memory regions in the map/unmap callbacks.
>   * Re-ordered functions in apple-gfx.m to group them by area of functionality.
>   * Improved comments and tweaked some names.
> 
> v7:
> 
>   * Use g_ptr_array_find() helper function
>   * Error handling coding style tweak
> 
>   hw/display/Kconfig          |   9 +
>   hw/display/apple-gfx-mmio.m | 281 +++++++++++++
>   hw/display/apple-gfx.h      |  65 +++
>   hw/display/apple-gfx.m      | 770 ++++++++++++++++++++++++++++++++++++
>   hw/display/meson.build      |   4 +
>   hw/display/trace-events     |  28 ++
>   meson.build                 |   4 +
>   7 files changed, 1161 insertions(+)
>   create mode 100644 hw/display/apple-gfx-mmio.m
>   create mode 100644 hw/display/apple-gfx.h
>   create mode 100644 hw/display/apple-gfx.m
> 
> diff --git a/hw/display/Kconfig b/hw/display/Kconfig
> index 2250c740078..6a9b7b19ada 100644
> --- a/hw/display/Kconfig
> +++ b/hw/display/Kconfig
> @@ -140,3 +140,12 @@ config XLNX_DISPLAYPORT
>   
>   config DM163
>       bool
> +
> +config MAC_PVG
> +    bool
> +    default y
> +
> +config MAC_PVG_MMIO
> +    bool
> +    depends on MAC_PVG && AARCH64
> +
> diff --git a/hw/display/apple-gfx-mmio.m b/hw/display/apple-gfx-mmio.m
> new file mode 100644
> index 00000000000..10f52b0797b
> --- /dev/null
> +++ b/hw/display/apple-gfx-mmio.m
> @@ -0,0 +1,281 @@
> +/*
> + * QEMU Apple ParavirtualizedGraphics.framework device, MMIO (arm64) variant
> + *
> + * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + *
> + * ParavirtualizedGraphics.framework is a set of libraries that macOS provides
> + * which implements 3d graphics passthrough to the host as well as a
> + * proprietary guest communication channel to drive it. This device model
> + * implements support to drive that library from within QEMU as an MMIO-based
> + * system device for macOS on arm64 VMs.
> + */
> +
> +#include "qemu/osdep.h"
> +#import <ParavirtualizedGraphics/ParavirtualizedGraphics.h>
> +#include "apple-gfx.h"
> +#include "monitor/monitor.h"
> +#include "hw/sysbus.h"
> +#include "hw/irq.h"
> +#include "trace.h"
> +#include "qemu/log.h"
> +
> +OBJECT_DECLARE_SIMPLE_TYPE(AppleGFXMMIOState, APPLE_GFX_MMIO)
> +
> +/*
> + * ParavirtualizedGraphics.Framework only ships header files for the PCI
> + * variant which does not include IOSFC descriptors and host devices. We add
> + * their definitions here so that we can also work with the ARM version.
> + */
> +typedef bool(^IOSFCRaiseInterrupt)(uint32_t vector);
> +typedef bool(^IOSFCUnmapMemory)(
> +    void *, void *, void *, void *, void *, void *);
> +typedef bool(^IOSFCMapMemory)(
> +    uint64_t phys, uint64_t len, bool ro, void **va, void *, void *);
> +
> +@interface PGDeviceDescriptor (IOSurfaceMapper)
> +@property (readwrite, nonatomic) bool usingIOSurfaceMapper;
> +@end
> +
> +@interface PGIOSurfaceHostDeviceDescriptor : NSObject
> +-(PGIOSurfaceHostDeviceDescriptor *)init;
> +@property (readwrite, nonatomic, copy, nullable) IOSFCMapMemory mapMemory;
> +@property (readwrite, nonatomic, copy, nullable) IOSFCUnmapMemory unmapMemory;
> +@property (readwrite, nonatomic, copy, nullable) IOSFCRaiseInterrupt raiseInterrupt;
> +@end
> +
> +@interface PGIOSurfaceHostDevice : NSObject
> +-(instancetype)initWithDescriptor:(PGIOSurfaceHostDeviceDescriptor *)desc;
> +-(uint32_t)mmioReadAtOffset:(size_t)offset;
> +-(void)mmioWriteAtOffset:(size_t)offset value:(uint32_t)value;
> +@end
> +
> +struct AppleGFXMapSurfaceMemoryJob;
> +struct AppleGFXMMIOState {
> +    SysBusDevice parent_obj;
> +
> +    AppleGFXState common;
> +
> +    qemu_irq irq_gfx;
> +    qemu_irq irq_iosfc;
> +    MemoryRegion iomem_iosfc;
> +    PGIOSurfaceHostDevice *pgiosfc;
> +};
> +
> +typedef struct AppleGFXMMIOJob {
> +    AppleGFXMMIOState *state;
> +    uint64_t offset;
> +    uint64_t value;
> +    bool completed;
> +} AppleGFXMMIOJob;
> +
> +static void iosfc_do_read(void *opaque)
> +{
> +    AppleGFXMMIOJob *job = opaque;
> +    job->value = [job->state->pgiosfc mmioReadAtOffset:job->offset];
> +    qatomic_set(&job->completed, true);
> +    aio_wait_kick();
> +}
> +
> +static uint64_t iosfc_read(void *opaque, hwaddr offset, unsigned size)
> +{
> +    AppleGFXMMIOJob job = {
> +        .state = opaque,
> +        .offset = offset,
> +        .completed = false,
> +    };
> +    dispatch_queue_t queue =
> +        dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
> +
> +    dispatch_async_f(queue, &job, iosfc_do_read);
> +    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
> +
> +    trace_apple_gfx_mmio_iosfc_read(offset, job.value);
> +    return job.value;
> +}
> +
> +static void iosfc_do_write(void *opaque)
> +{
> +    AppleGFXMMIOJob *job = opaque;
> +    [job->state->pgiosfc mmioWriteAtOffset:job->offset value:job->value];
> +    qatomic_set(&job->completed, true);
> +    aio_wait_kick();
> +}
> +
> +static void iosfc_write(void *opaque, hwaddr offset, uint64_t val,
> +                        unsigned size)
> +{
> +    AppleGFXMMIOJob job = {
> +        .state = opaque,
> +        .offset = offset,
> +        .value = val,
> +        .completed = false,
> +    };
> +    dispatch_queue_t queue =
> +        dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
> +
> +    dispatch_async_f(queue, &job, iosfc_do_write);
> +    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
> +
> +    trace_apple_gfx_mmio_iosfc_write(offset, val);
> +}
> +
> +static const MemoryRegionOps apple_iosfc_ops = {
> +    .read = iosfc_read,
> +    .write = iosfc_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 8,
> +    },
> +    .impl = {
> +        .min_access_size = 4,
> +        .max_access_size = 8,
> +    },
> +};
> +
> +static void raise_irq_bh(void *opaque)
> +{
> +    qemu_irq *irq = opaque;
> +
> +    qemu_irq_pulse(*irq);
> +}
> +
> +static void *apple_gfx_mmio_map_surface_memory(uint64_t guest_physical_address,
> +                                               uint64_t length, bool read_only)
> +{
> +    mach_vm_address_t mem;
> +    MemoryRegion *region = NULL;
> +
> +    RCU_READ_LOCK_GUARD();
> +    mem = apple_gfx_host_address_for_gpa_range(guest_physical_address,
> +                                               length, read_only, &region);
> +
> +    if (mem != 0) {
> +        memory_region_ref(region);
> +    }
> +
> +    return (void *)mem;
> +}
> +
> +static bool apple_gfx_mmio_unmap_surface_memory(void *virtual_address)

I'm nitpicking here, but virtual_address is somewhat confusing in QEMU 
as we could have host and guest virtual addresses. "Address" also often 
refers to a numeric type (e.g., uintptr_t).

memory_region_from_host() just calls the parameter "ptr" so we may 
follow what it does.

> +{
> +    MemoryRegion *region;
> +    ram_addr_t offset = 0;
> +
> +    RCU_READ_LOCK_GUARD();
> +    region = memory_region_from_host(virtual_address, &offset);
> +    if (!region) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "%s: memory at %p to be unmapped not "
> +                      "found.\n",
> +                      __func__,
> +                      virtual_address);
> +        return false;
> +    }
> +
> +    trace_apple_gfx_iosfc_unmap_memory_region(virtual_address, region);
> +    memory_region_unref(region);
> +    return true;
> +}
> +
> +static PGIOSurfaceHostDevice *apple_gfx_prepare_iosurface_host_device(
> +    AppleGFXMMIOState *s)
> +{
> +    PGIOSurfaceHostDeviceDescriptor *iosfc_desc =
> +        [PGIOSurfaceHostDeviceDescriptor new];
> +    PGIOSurfaceHostDevice *iosfc_host_dev = nil;
> +
> +    iosfc_desc.mapMemory =
> +        ^bool(uint64_t phys, uint64_t len, bool ro, void **va, void *e, void *f) {
> +            *va = apple_gfx_mmio_map_surface_memory(phys, len, ro);
> +
> +            trace_apple_gfx_iosfc_map_memory(phys, len, ro, va, e, f, *va);
> +
> +            return *va != NULL;
> +        };
> +
> +    iosfc_desc.unmapMemory =
> +        ^bool(void *va, void *b, void *c, void *d, void *e, void *f) {
> +            return apple_gfx_mmio_unmap_surface_memory(s);

I guess you meant to pass va here.

> +        };
> +
> +    iosfc_desc.raiseInterrupt = ^bool(uint32_t vector) {
> +        trace_apple_gfx_iosfc_raise_irq(vector);
> +        aio_bh_schedule_oneshot(qemu_get_aio_context(),
> +                                raise_irq_bh, &s->irq_iosfc);
> +        return true;
> +    };
> +
> +    iosfc_host_dev =
> +        [[PGIOSurfaceHostDevice alloc] initWithDescriptor:iosfc_desc];
> +    [iosfc_desc release];
> +    return iosfc_host_dev;
> +}
> +
> +static void apple_gfx_mmio_realize(DeviceState *dev, Error **errp)
> +{
> +    @autoreleasepool {
> +        AppleGFXMMIOState *s = APPLE_GFX_MMIO(dev);
> +        PGDeviceDescriptor *desc = [PGDeviceDescriptor new];
> +
> +        desc.raiseInterrupt = ^(uint32_t vector) {
> +            trace_apple_gfx_raise_irq(vector);
> +            aio_bh_schedule_oneshot(qemu_get_aio_context(),
> +                                    raise_irq_bh, &s->irq_gfx);
> +        };
> +
> +        desc.usingIOSurfaceMapper = true;
> +        s->pgiosfc = apple_gfx_prepare_iosurface_host_device(s);
> +
> +        apple_gfx_common_realize(&s->common, desc, errp);

s->pgiosfc will leak if apple_gfx_common_realize() sets errp.

> +
> +        [desc release];
> +        desc = nil;
> +    }
> +}
> +
> +static void apple_gfx_mmio_init(Object *obj)
> +{
> +    AppleGFXMMIOState *s = APPLE_GFX_MMIO(obj);
> +
> +    apple_gfx_common_init(obj, &s->common, TYPE_APPLE_GFX_MMIO);
> +
> +    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->common.iomem_gfx);
> +    memory_region_init_io(&s->iomem_iosfc, obj, &apple_iosfc_ops, s,
> +                          TYPE_APPLE_GFX_MMIO, 0x10000);
> +    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem_iosfc);
> +    sysbus_init_irq(SYS_BUS_DEVICE(s), &s->irq_gfx);
> +    sysbus_init_irq(SYS_BUS_DEVICE(s), &s->irq_iosfc);
> +}
> +
> +static void apple_gfx_mmio_reset(Object *obj, ResetType type)
> +{
> +    AppleGFXMMIOState *s = APPLE_GFX_MMIO(obj);
> +    [s->common.pgdev reset];
> +}
> +
> +
> +static void apple_gfx_mmio_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    ResettableClass *rc = RESETTABLE_CLASS(klass);
> +
> +    rc->phases.hold = apple_gfx_mmio_reset;
> +    dc->hotpluggable = false;
> +    dc->realize = apple_gfx_mmio_realize;
> +}
> +
> +static TypeInfo apple_gfx_mmio_types[] = {
> +    {
> +        .name          = TYPE_APPLE_GFX_MMIO,
> +        .parent        = TYPE_SYS_BUS_DEVICE,
> +        .instance_size = sizeof(AppleGFXMMIOState),
> +        .class_init    = apple_gfx_mmio_class_init,
> +        .instance_init = apple_gfx_mmio_init,
> +    }
> +};
> +DEFINE_TYPES(apple_gfx_mmio_types)
> diff --git a/hw/display/apple-gfx.h b/hw/display/apple-gfx.h
> new file mode 100644
> index 00000000000..91b55299338
> --- /dev/null
> +++ b/hw/display/apple-gfx.h
> @@ -0,0 +1,65 @@
> +/*
> + * Data structures and functions shared between variants of the macOS
> + * ParavirtualizedGraphics.framework based apple-gfx display adapter.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#ifndef QEMU_APPLE_GFX_H
> +#define QEMU_APPLE_GFX_H
> +
> +#define TYPE_APPLE_GFX_MMIO         "apple-gfx-mmio"
> +#define TYPE_APPLE_GFX_PCI          "apple-gfx-pci"
> +
> +#include "qemu/osdep.h"
> +#include <dispatch/dispatch.h>
> +#import <ParavirtualizedGraphics/ParavirtualizedGraphics.h>
> +#include "qemu/typedefs.h"
> +#include "exec/memory.h"
> +#include "ui/surface.h"
> +
> +@class PGDeviceDescriptor;
> +@protocol PGDevice;
> +@protocol PGDisplay;
> +@protocol MTLDevice;
> +@protocol MTLTexture;
> +@protocol MTLCommandQueue;
> +
> +typedef QTAILQ_HEAD(, PGTask_s) PGTaskList;
> +
> +typedef struct AppleGFXState {
> +    /* Initialised on init/realize() */
> +    MemoryRegion iomem_gfx;
> +    id<PGDevice> pgdev;
> +    id<PGDisplay> pgdisp;
> +    QemuConsole *con;
> +    id<MTLDevice> mtl;
> +    id<MTLCommandQueue> mtl_queue;
> +    dispatch_queue_t render_queue;
> +
> +    /* List `tasks` is protected by task_mutex */
> +    QemuMutex task_mutex;
> +    PGTaskList tasks;
> +
> +    /* Mutable state (BQL protected) */
> +    QEMUCursor *cursor;
> +    DisplaySurface *surface;
> +    id<MTLTexture> texture;
> +    int32_t pending_frames; /* # guest frames in the rendering pipeline */

int8_t or uint8_t should be sufficient here.

> +    bool gfx_update_requested; /* QEMU display system wants a new frame */
> +    bool new_frame_ready; /* Guest has rendered a frame, ready to be used */
> +    bool using_managed_texture_storage;
> +
> +    /* Mutable state (atomic) */
> +    bool cursor_show;
> +} AppleGFXState;
> +
> +void apple_gfx_common_init(Object *obj, AppleGFXState *s, const char* obj_name);
> +void apple_gfx_common_realize(AppleGFXState *s, PGDeviceDescriptor *desc,
> +                              Error **errp);
> +uintptr_t apple_gfx_host_address_for_gpa_range(uint64_t guest_physical,
> +                                               uint64_t length, bool read_only,
> +                                               MemoryRegion **mapping_in_region);
> +
> +#endif
> +
> diff --git a/hw/display/apple-gfx.m b/hw/display/apple-gfx.m
> new file mode 100644
> index 00000000000..b0428648394
> --- /dev/null
> +++ b/hw/display/apple-gfx.m
> @@ -0,0 +1,770 @@
> +/*
> + * QEMU Apple ParavirtualizedGraphics.framework device
> + *
> + * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + *
> + * ParavirtualizedGraphics.framework is a set of libraries that macOS provides
> + * which implements 3d graphics passthrough to the host as well as a
> + * proprietary guest communication channel to drive it. This device model
> + * implements support to drive that library from within QEMU.
> + */
> +
> +#include "qemu/osdep.h"
> +#import <ParavirtualizedGraphics/ParavirtualizedGraphics.h>
> +#include <mach/mach_vm.h>
> +#include "apple-gfx.h"
> +#include "trace.h"
> +#include "qemu-main.h"
> +#include "exec/address-spaces.h"
> +#include "migration/blocker.h"
> +#include "monitor/monitor.h"
> +#include "qemu/main-loop.h"
> +#include "qemu/cutils.h"
> +#include "qemu/log.h"
> +#include "qapi/visitor.h"
> +#include "qapi/error.h"
> +#include "sysemu/dma.h"
> +#include "ui/console.h"
> +
> +static const PGDisplayCoord_t apple_gfx_modes[] = {
> +    { .x = 1440, .y = 1080 },
> +    { .x = 1280, .y = 1024 },
> +};
> +
> +/* ------ PGTask and task operations: new/destroy/map/unmap ------ */
> +
> +/*
> + * This implements the type declared in <ParavirtualizedGraphics/PGDevice.h>
> + * which is opaque from the framework's point of view. It is used in callbacks
> + * in the form of its typedef PGTask_t, which also already exists in the
> + * framework headers.
> + *
> + * A "task" in PVG terminology represents a host-virtual contiguous address
> + * range which is reserved in a large chunk on task creation. The mapMemory
> + * callback then requests ranges of guest system memory (identified by their
> + * GPA) to be mapped into subranges of this reserved address space.
> + * This type of operation isn't well-supported by QEMU's memory subsystem,
> + * but it is fortunately trivial to achieve with Darwin's mach_vm_remap() call,
> + * which allows us to refer to the same backing memory via multiple virtual
> + * address ranges. The Mach VM APIs are therefore used throughout for managing
> + * task memory.
> + */
> +struct PGTask_s {
> +    QTAILQ_ENTRY(PGTask_s) node;
> +    AppleGFXState *s;
> +    mach_vm_address_t address;
> +    uint64_t len;
> +    /*
> +     * All unique MemoryRegions for which a mapping has been created in in this
> +     * task, and on which we have thus called memory_region_ref(). There are
> +     * usually very few regions of system RAM in total, so we expect this array
> +     * to be very short. Therefore, no need for sorting or fancy search
> +     * algorithms, linear search will do.
> +     * Protected by AppleGFXState's task_mutex.
> +     */
> +    GPtrArray *mapped_regions;
> +};
> +
> +static Error *apple_gfx_mig_blocker;
> +
> +static PGTask_t *apple_gfx_new_task(AppleGFXState *s, uint64_t len)
> +{
> +    mach_vm_address_t task_mem;
> +    PGTask_t *task;
> +    kern_return_t r;
> +
> +    r = mach_vm_allocate(mach_task_self(), &task_mem, len, VM_FLAGS_ANYWHERE);
> +    if (r != KERN_SUCCESS) {
> +        return NULL;
> +    }
> +
> +    task = g_new0(PGTask_t, 1);
> +    task->s = s;
> +    task->address = task_mem;
> +    task->len = len;
> +    task->mapped_regions = g_ptr_array_sized_new(2 /* Usually enough */);
> +
> +    QEMU_LOCK_GUARD(&s->task_mutex);
> +    QTAILQ_INSERT_TAIL(&s->tasks, task, node);
> +
> +    return task;
> +}
> +
> +static void apple_gfx_destroy_task(AppleGFXState *s, PGTask_t *task)
> +{
> +    GPtrArray *regions = task->mapped_regions;
> +    MemoryRegion *region;
> +    size_t i;
> +
> +    for (i = 0; i < regions->len; ++i) {
> +        region = g_ptr_array_index(regions, i);
> +        memory_region_unref(region);
> +    }
> +    g_ptr_array_unref(regions);
> +
> +    mach_vm_deallocate(mach_task_self(), task->address, task->len);
> +
> +    QEMU_LOCK_GUARD(&s->task_mutex);
> +    QTAILQ_REMOVE(&s->tasks, task, node);
> +    g_free(task);
> +}
> +
> +uintptr_t apple_gfx_host_address_for_gpa_range(uint64_t guest_physical,
> +                                               uint64_t length, bool read_only,
> +                                               MemoryRegion **mapping_in_region)
> +{
> +    MemoryRegion *ram_region;
> +    uintptr_t host_address;
> +    hwaddr ram_region_offset = 0;
> +    hwaddr ram_region_length = length;
> +
> +    ram_region = address_space_translate(&address_space_memory,
> +                                         guest_physical,
> +                                         &ram_region_offset,
> +                                         &ram_region_length, !read_only,
> +                                         MEMTXATTRS_UNSPECIFIED);
> +
> +    if (!ram_region || ram_region_length < length ||
> +        !memory_access_is_direct(ram_region, !read_only)) {
> +        return 0;
> +    }
> +
> +    host_address = (uintptr_t)memory_region_get_ram_ptr(ram_region);
> +    if (host_address == 0) {
> +        return 0;
> +    }
> +    host_address += ram_region_offset;
> +    *mapping_in_region = ram_region;
> +    return host_address;
> +}
> +
> +/* Returns false if the region is already in the array */
> +static bool add_new_region(GPtrArray *regions, MemoryRegion *region)
> +{
> +    guint found_index;
> +
> +    if (g_ptr_array_find(regions, region, &found_index)) {

You can pass NULL instead of &found_index.

> +        return false;
> +    }
> +
> +    g_ptr_array_add(regions, region);
> +    return true;
> +}
> +
> +static bool apple_gfx_task_map_memory(AppleGFXState *s, PGTask_t *task,
> +                                      uint64_t virtual_offset,
> +                                      PGPhysicalMemoryRange_t *ranges,
> +                                      uint32_t range_count, bool read_only)
> +{
> +    kern_return_t r;
> +    mach_vm_address_t target, source;
> +    vm_prot_t cur_protection, max_protection;
> +    bool success = true;
> +    MemoryRegion *region;
> +
> +    RCU_READ_LOCK_GUARD();
> +    QEMU_LOCK_GUARD(&s->task_mutex);
> +
> +    trace_apple_gfx_map_memory(task, range_count, virtual_offset, read_only);
> +    for (int i = 0; i < range_count; i++) {
> +        PGPhysicalMemoryRange_t *range = &ranges[i];
> +
> +        target = task->address + virtual_offset;
> +        virtual_offset += range->physicalLength;
> +
> +        trace_apple_gfx_map_memory_range(i, range->physicalAddress,
> +                                         range->physicalLength);
> +
> +        region = NULL;
> +        source = apple_gfx_host_address_for_gpa_range(range->physicalAddress,
> +                                                      range->physicalLength,
> +                                                      read_only, &region);
> +        if (source == 0) {
> +            success = false;
> +            continue;
> +        }
> +
> +        if (add_new_region(task->mapped_regions, region)) {
> +            memory_region_ref(region);
> +        }
> +
> +        cur_protection = 0;
> +        max_protection = 0;
> +        // Map guest RAM at range->physicalAddress into PG task memory range
> +        r = mach_vm_remap(mach_task_self(),
> +                          &target, range->physicalLength, vm_page_size - 1,
> +                          VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE,
> +                          mach_task_self(),
> +                          source, false /* shared mapping, no copy */,
> +                          &cur_protection, &max_protection,
> +                          VM_INHERIT_COPY);
> +        trace_apple_gfx_remap(r, source, target);
> +        g_assert(r == KERN_SUCCESS);
> +    }
> +
> +    return success;
> +}
> +
> +static void apple_gfx_task_unmap_memory(AppleGFXState *s, PGTask_t *task,
> +                                        uint64_t virtual_offset, uint64_t length)
> +{
> +    kern_return_t r;
> +    mach_vm_address_t range_address;
> +
> +    trace_apple_gfx_unmap_memory(task, virtual_offset, length);
> +
> +    /*
> +     * Replace task memory range with fresh 0 pages, undoing the mapping
> +     * from guest RAM.
> +     */
> +    range_address = task->address + virtual_offset;
> +    r = mach_vm_allocate(mach_task_self(), &range_address, length,
> +                         VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE);
> +    g_assert(r == KERN_SUCCESS);
> +}
> +
> +/* ------ Rendering and frame management ------ */
> +
> +static void apple_gfx_render_frame_completed(AppleGFXState *s,
> +                                             uint32_t width, uint32_t height);
> +
> +static void apple_gfx_render_new_frame_bql_unlock(AppleGFXState *s)
> +{
> +    BOOL r;
> +    bool managed_texture = s->using_managed_texture_storage;
> +    uint32_t width = surface_width(s->surface);
> +    uint32_t height = surface_height(s->surface);
> +    MTLRegion region = MTLRegionMake2D(0, 0, width, height);
> +    id<MTLCommandBuffer> command_buffer = [s->mtl_queue commandBuffer];
> +    id<MTLTexture> texture = s->texture;
> +
> +    assert(bql_locked());
> +    [texture retain];
> +
> +    bql_unlock();
> +
> +    /* This is not safe to call from the BQL due to PVG-internal locks causing
> +     * deadlocks. */
> +    r = [s->pgdisp encodeCurrentFrameToCommandBuffer:command_buffer
> +                                             texture:texture
> +                                              region:region];
> +    if (!r) {
> +        [texture release];
> +        bql_lock();
> +        --s->pending_frames;
> +        bql_unlock();
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: encodeCurrentFrameToCommandBuffer:texture:region: "
> +                      "failed\n", __func__);
> +        return;
> +    }
> +
> +    if (managed_texture) {
> +        /* "Managed" textures exist in both VRAM and RAM and must be synced. */
> +        id<MTLBlitCommandEncoder> blit = [command_buffer blitCommandEncoder];
> +        [blit synchronizeResource:texture];
> +        [blit endEncoding];
> +    }
> +    [texture release];
> +    [command_buffer addCompletedHandler:
> +        ^(id<MTLCommandBuffer> cb)
> +        {
> +            dispatch_async(s->render_queue, ^{
> +                apple_gfx_render_frame_completed(s, width, height);
> +            });
> +        }];
> +    [command_buffer commit];
> +}
> +
> +static void copy_mtl_texture_to_surface_mem(id<MTLTexture> texture, void *vram)
> +{
> +    /* TODO: Skip this entirely on a pure Metal or headless/guest-only
> +     * rendering path, else use a blit command encoder? Needs careful
> +     * (double?) buffering design. */
> +    size_t width = texture.width, height = texture.height;
> +    MTLRegion region = MTLRegionMake2D(0, 0, width, height);
> +    [texture getBytes:vram
> +          bytesPerRow:(width * 4)
> +        bytesPerImage:(width * height * 4)
> +           fromRegion:region
> +          mipmapLevel:0
> +                slice:0];
> +}
> +
> +static void apple_gfx_render_frame_completed(AppleGFXState *s,
> +                                             uint32_t width, uint32_t height)
> +{
> +    bql_lock();
> +    --s->pending_frames;
> +    assert(s->pending_frames >= 0);
> +
> +    /* Only update display if mode hasn't changed since we started rendering. */
> +    if (width == surface_width(s->surface) &&
> +        height == surface_height(s->surface)) {
> +        copy_mtl_texture_to_surface_mem(s->texture, surface_data(s->surface));
> +        if (s->gfx_update_requested) {
> +            s->gfx_update_requested = false;
> +            dpy_gfx_update_full(s->con);
> +            graphic_hw_update_done(s->con);
> +            s->new_frame_ready = false;
> +        } else {
> +            s->new_frame_ready = true;
> +        }
> +    }
> +    if (s->pending_frames > 0) {
> +        apple_gfx_render_new_frame_bql_unlock(s);
> +    } else {
> +        bql_unlock();
> +    }
> +}
> +
> +static void apple_gfx_fb_update_display(void *opaque)
> +{
> +    AppleGFXState *s = opaque;
> +
> +    assert(bql_locked());
> +    if (s->new_frame_ready) {
> +        dpy_gfx_update_full(s->con);
> +        s->new_frame_ready = false;
> +        graphic_hw_update_done(s->con);
> +    } else if (s->pending_frames > 0) {
> +        s->gfx_update_requested = true;
> +    } else {
> +        graphic_hw_update_done(s->con);
> +    }
> +}
> +
> +static const GraphicHwOps apple_gfx_fb_ops = {
> +    .gfx_update = apple_gfx_fb_update_display,
> +    .gfx_update_async = true,
> +};
> +
> +/* ------ Mouse cursor and display mode setting ------ */
> +
> +static void set_mode(AppleGFXState *s, uint32_t width, uint32_t height)
> +{
> +    MTLTextureDescriptor *textureDescriptor;
> +
> +    if (s->surface &&
> +        width == surface_width(s->surface) &&
> +        height == surface_height(s->surface)) {
> +        return;
> +    }
> +
> +    [s->texture release];
> +
> +    s->surface = qemu_create_displaysurface(width, height);
> +
> +    @autoreleasepool {
> +        textureDescriptor =
> +            [MTLTextureDescriptor
> +                texture2DDescriptorWithPixelFormat:MTLPixelFormatBGRA8Unorm
> +                                             width:width
> +                                            height:height
> +                                         mipmapped:NO];
> +        textureDescriptor.usage = s->pgdisp.minimumTextureUsage;
> +        s->texture = [s->mtl newTextureWithDescriptor:textureDescriptor];
> +    }
> +
> +    s->using_managed_texture_storage =
> +        (s->texture.storageMode == MTLStorageModeManaged);
> +    dpy_gfx_replace_surface(s->con, s->surface);
> +}
> +
> +static void update_cursor(AppleGFXState *s)
> +{
> +    assert(bql_locked());
> +    dpy_mouse_set(s->con, s->pgdisp.cursorPosition.x,
> +                  s->pgdisp.cursorPosition.y, qatomic_read(&s->cursor_show));
> +}
> +
> +static void update_cursor_bh(void *opaque)
> +{
> +    AppleGFXState *s = opaque;
> +    update_cursor(s);
> +}
> +
> +typedef struct AppleGFXSetCursorGlyphJob {
> +    AppleGFXState *s;
> +    NSBitmapImageRep *glyph;
> +    PGDisplayCoord_t hotspot;
> +} AppleGFXSetCursorGlyphJob;
> +
> +static void set_cursor_glyph(void *opaque)
> +{
> +    AppleGFXSetCursorGlyphJob *job = opaque;
> +    AppleGFXState *s = job->s;
> +    NSBitmapImageRep *glyph = job->glyph;
> +    uint32_t bpp = glyph.bitsPerPixel;
> +    size_t width = glyph.pixelsWide;
> +    size_t height = glyph.pixelsHigh;
> +    size_t padding_bytes_per_row = glyph.bytesPerRow - width * 4;
> +    const uint8_t* px_data = glyph.bitmapData;
> +
> +    trace_apple_gfx_cursor_set(bpp, width, height);
> +
> +    if (s->cursor) {
> +        cursor_unref(s->cursor);
> +        s->cursor = NULL;
> +    }
> +
> +    if (bpp == 32) { /* Shouldn't be anything else, but just to be safe...*/
> +        s->cursor = cursor_alloc(width, height);
> +        s->cursor->hot_x = job->hotspot.x;
> +        s->cursor->hot_y = job->hotspot.y;
> +
> +        uint32_t *dest_px = s->cursor->data;
> +
> +        for (size_t y = 0; y < height; ++y) {
> +            for (size_t x = 0; x < width; ++x) {
> +                /* NSBitmapImageRep's red & blue channels are swapped
> +                 * compared to QEMUCursor's. */
> +                *dest_px =
> +                    (px_data[0] << 16u) |
> +                    (px_data[1] <<  8u) |
> +                    (px_data[2] <<  0u) |
> +                    (px_data[3] << 24u);
> +                ++dest_px;
> +                px_data += 4;
> +            }
> +            px_data += padding_bytes_per_row;
> +        }
> +        dpy_cursor_define(s->con, s->cursor);
> +        update_cursor(s);
> +    }
> +    [glyph release];
> +
> +    g_free(job);
> +}
> +
> +/* ------ DMA (device reading system memory) ------ */
> +
> +typedef struct AppleGFXReadMemoryJob {
> +    QemuSemaphore sem;
> +    hwaddr physical_address;
> +    uint64_t length;
> +    void *dst;
> +    bool success;
> +} AppleGFXReadMemoryJob;
> +
> +static void apple_gfx_do_read_memory(void *opaque)
> +{
> +    AppleGFXReadMemoryJob *job = opaque;
> +    MemTxResult r;
> +
> +    r = dma_memory_read(&address_space_memory, job->physical_address,
> +                        job->dst, job->length, MEMTXATTRS_UNSPECIFIED);
> +    job->success = r == MEMTX_OK;
> +
> +    qemu_sem_post(&job->sem);
> +}
> +
> +static bool apple_gfx_read_memory(AppleGFXState *s, hwaddr physical_address,
> +                                  uint64_t length, void *dst)
> +{
> +    AppleGFXReadMemoryJob job = {
> +        .physical_address = physical_address, .length = length, .dst = dst
> +    };
> +
> +    trace_apple_gfx_read_memory(physical_address, length, dst);
> +
> +    /* Performing DMA requires BQL, so do it in a BH. */
> +    qemu_sem_init(&job.sem, 0);
> +    aio_bh_schedule_oneshot(qemu_get_aio_context(),
> +                            apple_gfx_do_read_memory, &job);
> +    qemu_sem_wait(&job.sem);
> +    qemu_sem_destroy(&job.sem);
> +    return job.success;
> +}
> +
> +/* ------ Memory-mapped device I/O operations ------ */
> +
> +static dispatch_queue_t get_background_queue(void)
> +{
> +    return dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
> +}
> +
> +typedef struct AppleGFXIOJob {
> +    AppleGFXState *state;
> +    uint64_t offset;
> +    uint64_t value;
> +    bool completed;
> +} AppleGFXIOJob;
> +
> +static void apple_gfx_do_read(void *opaque)
> +{
> +    AppleGFXIOJob *job = opaque;
> +    job->value = [job->state->pgdev mmioReadAtOffset:job->offset];
> +    qatomic_set(&job->completed, true);
> +    aio_wait_kick();
> +}
> +
> +static uint64_t apple_gfx_read(void *opaque, hwaddr offset, unsigned size)
> +{
> +    AppleGFXIOJob job = {
> +        .state = opaque,
> +        .offset = offset,
> +        .completed = false,
> +    };
> +    dispatch_queue_t queue = get_background_queue();
> +
> +    dispatch_async_f(queue, &job, apple_gfx_do_read);
> +    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
> +
> +    trace_apple_gfx_read(offset, job.value);
> +    return job.value;
> +}
> +
> +static void apple_gfx_do_write(void *opaque)
> +{
> +    AppleGFXIOJob *job = opaque;
> +    [job->state->pgdev mmioWriteAtOffset:job->offset value:job->value];
> +    qatomic_set(&job->completed, true);
> +    aio_wait_kick();
> +}
> +
> +static void apple_gfx_write(void *opaque, hwaddr offset, uint64_t val,
> +                            unsigned size)
> +{
> +    /*
> +     * The methods mmioReadAtOffset: and especially mmioWriteAtOffset: can
> +     * trigger synchronous operations on other dispatch queues, which in turn
> +     * may call back out on one or more of the callback blocks. For this reason,
> +     * and as we are holding the BQL, we invoke the I/O methods on a pool
> +     * thread and handle AIO tasks while we wait. Any work in the callbacks
> +     * requiring the BQL will in turn schedule BHs which this thread will
> +     * process while waiting.
> +     */
> +    AppleGFXIOJob job = {
> +        .state = opaque,
> +        .offset = offset,
> +        .value = val,
> +        .completed = false,
> +    };
> +    dispatch_queue_t queue = get_background_queue();
> +
> +    dispatch_async_f(queue, &job, apple_gfx_do_write);
> +    AIO_WAIT_WHILE(NULL, !qatomic_read(&job.completed));
> +
> +    trace_apple_gfx_write(offset, val);
> +}
> +
> +static const MemoryRegionOps apple_gfx_ops = {
> +    .read = apple_gfx_read,
> +    .write = apple_gfx_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 8,
> +    },
> +    .impl = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +};
> +
> +static size_t apple_gfx_get_default_mmio_range_size(void)
> +{
> +    size_t mmio_range_size;
> +    @autoreleasepool {
> +        PGDeviceDescriptor *desc = [PGDeviceDescriptor new];
> +        mmio_range_size = desc.mmioLength;
> +        [desc release];
> +    }
> +    return mmio_range_size;
> +}
> +
> +/* ------ Initialisation and startup ------ */
> +
> +void apple_gfx_common_init(Object *obj, AppleGFXState *s, const char* obj_name)
> +{
> +    size_t mmio_range_size = apple_gfx_get_default_mmio_range_size();
> +
> +    trace_apple_gfx_common_init(obj_name, mmio_range_size);
> +    memory_region_init_io(&s->iomem_gfx, obj, &apple_gfx_ops, s, obj_name,
> +                          mmio_range_size);
> +
> +    /* TODO: PVG framework supports serialising device state: integrate it! */
> +}
> +
> +static void apple_gfx_register_task_mapping_handlers(AppleGFXState *s,
> +                                                     PGDeviceDescriptor *desc)
> +{
> +    desc.createTask = ^(uint64_t vmSize, void * _Nullable * _Nonnull baseAddress) {
> +        PGTask_t *task = apple_gfx_new_task(s, vmSize);
> +        *baseAddress = (void *)task->address;
> +        trace_apple_gfx_create_task(vmSize, *baseAddress);
> +        return task;
> +    };
> +
> +    desc.destroyTask = ^(PGTask_t * _Nonnull task) {
> +        trace_apple_gfx_destroy_task(task, task->mapped_regions->len);
> +
> +        apple_gfx_destroy_task(s, task);
> +    };
> +
> +    desc.mapMemory = ^bool(PGTask_t * _Nonnull task, uint32_t range_count,
> +                           uint64_t virtual_offset, bool read_only,
> +                           PGPhysicalMemoryRange_t * _Nonnull ranges) {
> +        return apple_gfx_task_map_memory(s, task, virtual_offset,
> +                                         ranges, range_count, read_only);
> +    };
> +
> +    desc.unmapMemory = ^bool(PGTask_t * _Nonnull task, uint64_t virtual_offset,
> +                             uint64_t length) {
> +        apple_gfx_task_unmap_memory(s, task, virtual_offset, length);
> +        return true;
> +    };
> +
> +    desc.readMemory = ^bool(uint64_t physical_address, uint64_t length,
> +                            void * _Nonnull dst) {
> +        return apple_gfx_read_memory(s, physical_address, length, dst);
> +    };
> +}
> +
> +static PGDisplayDescriptor *apple_gfx_prepare_display_descriptor(AppleGFXState *s)
> +{
> +    PGDisplayDescriptor *disp_desc = [PGDisplayDescriptor new];
> +
> +    disp_desc.name = @"QEMU display";
> +    disp_desc.sizeInMillimeters = NSMakeSize(400., 300.); /* A 20" display */
> +    disp_desc.queue = dispatch_get_main_queue();
> +    disp_desc.newFrameEventHandler = ^(void) {
> +        trace_apple_gfx_new_frame();
> +        dispatch_async(s->render_queue, ^{
> +            /* Drop frames if we get too far ahead. */
> +            bql_lock();
> +            if (s->pending_frames >= 2) {
> +                bql_unlock();
> +                return;
> +            }
> +            ++s->pending_frames;
> +            if (s->pending_frames > 1) {
> +                bql_unlock();
> +                return;
> +            }
> +            @autoreleasepool {
> +                apple_gfx_render_new_frame_bql_unlock(s);
> +            }
> +        });
> +    };
> +    disp_desc.modeChangeHandler = ^(PGDisplayCoord_t sizeInPixels,
> +                                    OSType pixelFormat) {
> +        trace_apple_gfx_mode_change(sizeInPixels.x, sizeInPixels.y);
> +
> +        BQL_LOCK_GUARD();
> +        set_mode(s, sizeInPixels.x, sizeInPixels.y);
> +    };
> +    disp_desc.cursorGlyphHandler = ^(NSBitmapImageRep *glyph,
> +                                     PGDisplayCoord_t hotspot) {
> +        AppleGFXSetCursorGlyphJob *job = g_malloc0(sizeof(*job));
> +        job->s = s;
> +        job->glyph = glyph;
> +        job->hotspot = hotspot;
> +        [glyph retain];
> +        aio_bh_schedule_oneshot(qemu_get_aio_context(),
> +                                set_cursor_glyph, job);
> +    };
> +    disp_desc.cursorShowHandler = ^(BOOL show) {
> +        trace_apple_gfx_cursor_show(show);
> +        qatomic_set(&s->cursor_show, show);
> +        aio_bh_schedule_oneshot(qemu_get_aio_context(),
> +                                update_cursor_bh, s);
> +    };
> +    disp_desc.cursorMoveHandler = ^(void) {
> +        trace_apple_gfx_cursor_move();
> +        aio_bh_schedule_oneshot(qemu_get_aio_context(),
> +                                update_cursor_bh, s);
> +    };
> +
> +    return disp_desc;
> +}
> +
> +static NSArray<PGDisplayMode*>* apple_gfx_prepare_display_mode_array(void)
> +{
> +    PGDisplayMode *modes[ARRAY_SIZE(apple_gfx_modes)];
> +    NSArray<PGDisplayMode*>* mode_array = nil;
> +    int i;
> +
> +    for (i = 0; i < ARRAY_SIZE(apple_gfx_modes); i++) {
> +        modes[i] =
> +            [[PGDisplayMode alloc] initWithSizeInPixels:apple_gfx_modes[i] refreshRateInHz:60.];
> +    }
> +
> +    mode_array = [NSArray arrayWithObjects:modes count:ARRAY_SIZE(apple_gfx_modes)];
> +
> +    for (i = 0; i < ARRAY_SIZE(apple_gfx_modes); i++) {
> +        [modes[i] release];
> +        modes[i] = nil;
> +    }
> +
> +    return mode_array;
> +}
> +
> +static id<MTLDevice> copy_suitable_metal_device(void)
> +{
> +    id<MTLDevice> dev = nil;
> +    NSArray<id<MTLDevice>> *devs = MTLCopyAllDevices();
> +
> +    /* Prefer a unified memory GPU. Failing that, pick a non-removable GPU. */
> +    for (size_t i = 0; i < devs.count; ++i) {
> +        if (devs[i].hasUnifiedMemory) {
> +            dev = devs[i];
> +            break;
> +        }
> +        if (!devs[i].removable) {
> +            dev = devs[i];
> +        }
> +    }
> +
> +    if (dev != nil) {
> +        [dev retain];
> +    } else {
> +        dev = MTLCreateSystemDefaultDevice();
> +    }
> +    [devs release];
> +
> +    return dev;
> +}
> +
> +void apple_gfx_common_realize(AppleGFXState *s, PGDeviceDescriptor *desc,
> +                              Error **errp)
> +{
> +    PGDisplayDescriptor *disp_desc = nil;
> +
> +    if (apple_gfx_mig_blocker == NULL) {
> +        error_setg(&apple_gfx_mig_blocker,
> +                  "Migration state blocked by apple-gfx display device");
> +        if (migrate_add_blocker(&apple_gfx_mig_blocker, errp) < 0) {
> +            return;
> +        }
> +    }
> +
> +    qemu_mutex_init(&s->task_mutex);
> +    QTAILQ_INIT(&s->tasks);
> +    s->render_queue = dispatch_queue_create("apple-gfx.render",
> +                                            DISPATCH_QUEUE_SERIAL);
> +    s->mtl = copy_suitable_metal_device();
> +    s->mtl_queue = [s->mtl newCommandQueue];
> +
> +    desc.device = s->mtl;
> +
> +    apple_gfx_register_task_mapping_handlers(s, desc);
> +
> +    s->pgdev = PGNewDeviceWithDescriptor(desc);
> +
> +    disp_desc = apple_gfx_prepare_display_descriptor(s);
> +    s->pgdisp = [s->pgdev newDisplayWithDescriptor:disp_desc
> +                                              port:0 serialNum:1234];
> +    [disp_desc release];
> +    s->pgdisp.modeList = apple_gfx_prepare_display_mode_array();
> +
> +    s->con = graphic_console_init(NULL, 0, &apple_gfx_fb_ops, s);
> +
> +    qatomic_set(&s->cursor_show, true);
> +}
> diff --git a/hw/display/meson.build b/hw/display/meson.build
> index 20a94973fa2..619e642905a 100644
> --- a/hw/display/meson.build
> +++ b/hw/display/meson.build
> @@ -61,6 +61,10 @@ system_ss.add(when: 'CONFIG_ARTIST', if_true: files('artist.c'))
>   
>   system_ss.add(when: 'CONFIG_ATI_VGA', if_true: [files('ati.c', 'ati_2d.c', 'ati_dbg.c'), pixman])
>   
> +system_ss.add(when: 'CONFIG_MAC_PVG',         if_true: [files('apple-gfx.m'), pvg, metal])
> +if cpu == 'aarch64'
> +  system_ss.add(when: 'CONFIG_MAC_PVG_MMIO',  if_true: [files('apple-gfx-mmio.m'), pvg, metal])
> +endif
>   
>   if config_all_devices.has_key('CONFIG_VIRTIO_GPU')
>     virtio_gpu_ss = ss.source_set()
> diff --git a/hw/display/trace-events b/hw/display/trace-events
> index d26d663f963..260eab9146d 100644
> --- a/hw/display/trace-events
> +++ b/hw/display/trace-events
> @@ -194,3 +194,31 @@ dm163_bits_ppi(unsigned dest_width) "dest_width : %u"
>   dm163_leds(int led, uint32_t value) "led %d: 0x%x"
>   dm163_channels(int channel, uint8_t value) "channel %d: 0x%x"
>   dm163_refresh_rate(uint32_t rr) "refresh rate %d"
> +
> +# apple-gfx.m
> +apple_gfx_read(uint64_t offset, uint64_t res) "offset=0x%"PRIx64" res=0x%"PRIx64
> +apple_gfx_write(uint64_t offset, uint64_t val) "offset=0x%"PRIx64" val=0x%"PRIx64
> +apple_gfx_create_task(uint32_t vm_size, void *va) "vm_size=0x%x base_addr=%p"
> +apple_gfx_destroy_task(void *task, unsigned int num_mapped_regions) "task=%p, task->mapped_regions->len=%u"
> +apple_gfx_map_memory(void *task, uint32_t range_count, uint64_t virtual_offset, uint32_t read_only) "task=%p range_count=0x%x virtual_offset=0x%"PRIx64" read_only=%d"
> +apple_gfx_map_memory_range(uint32_t i, uint64_t phys_addr, uint64_t phys_len) "[%d] phys_addr=0x%"PRIx64" phys_len=0x%"PRIx64
> +apple_gfx_remap(uint64_t retval, uint64_t source, uint64_t target) "retval=%"PRId64" source=0x%"PRIx64" target=0x%"PRIx64
> +apple_gfx_unmap_memory(void *task, uint64_t virtual_offset, uint64_t length) "task=%p virtual_offset=0x%"PRIx64" length=0x%"PRIx64
> +apple_gfx_read_memory(uint64_t phys_address, uint64_t length, void *dst) "phys_addr=0x%"PRIx64" length=0x%"PRIx64" dest=%p"
> +apple_gfx_raise_irq(uint32_t vector) "vector=0x%x"
> +apple_gfx_new_frame(void) ""
> +apple_gfx_mode_change(uint64_t x, uint64_t y) "x=%"PRId64" y=%"PRId64
> +apple_gfx_cursor_set(uint32_t bpp, uint64_t width, uint64_t height) "bpp=%d width=%"PRId64" height=0x%"PRId64
> +apple_gfx_cursor_show(uint32_t show) "show=%d"
> +apple_gfx_cursor_move(void) ""
> +apple_gfx_common_init(const char *device_name, size_t mmio_size) "device: %s; MMIO size: %zu bytes"
> +
> +# apple-gfx-mmio.m
> +apple_gfx_mmio_iosfc_read(uint64_t offset, uint64_t res) "offset=0x%"PRIx64" res=0x%"PRIx64
> +apple_gfx_mmio_iosfc_write(uint64_t offset, uint64_t val) "offset=0x%"PRIx64" val=0x%"PRIx64
> +apple_gfx_iosfc_map_memory(uint64_t phys, uint64_t len, uint32_t ro, void *va, void *e, void *f, void* va_result) "phys=0x%"PRIx64" len=0x%"PRIx64" ro=%d va=%p e=%p f=%p -> *va=%p"
> +apple_gfx_iosfc_map_memory_new_region(size_t i, void *region, uint64_t start, uint64_t end) "index=%zu, region=%p, 0x%"PRIx64"-0x%"PRIx64
> +apple_gfx_iosfc_unmap_memory(void *a, void *b, void *c, void *d, void *e, void *f) "a=%p b=%p c=%p d=%p e=%p f=%p"
> +apple_gfx_iosfc_unmap_memory_region(void* mem, void *region) "unmapping @ %p from memory region %p"
> +apple_gfx_iosfc_raise_irq(uint32_t vector) "vector=0x%x"
> +
> diff --git a/meson.build b/meson.build
> index c386593c527..b1770ee39ff 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -769,6 +769,8 @@ socket = []
>   version_res = []
>   coref = []
>   iokit = []
> +pvg = []
> +metal = []
>   emulator_link_args = []
>   midl = not_found
>   widl = not_found
> @@ -790,6 +792,8 @@ elif host_os == 'darwin'
>     coref = dependency('appleframeworks', modules: 'CoreFoundation')
>     iokit = dependency('appleframeworks', modules: 'IOKit', required: false)
>     host_dsosuf = '.dylib'
> +  pvg = dependency('appleframeworks', modules: 'ParavirtualizedGraphics')
> +  metal = dependency('appleframeworks', modules: 'Metal')
>   elif host_os == 'sunos'
>     socket = [cc.find_library('socket'),
>               cc.find_library('nsl'),