From: Magnus Kulke <magnuskulke@linux.microsoft.com>

To set the local interrupt controller state, perform hv calls retrieving
partition state from the hypervisor.

Signed-off-by: Magnus Kulke <magnuskulke@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250916164847.77883-18-magnuskulke@linux.microsoft.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/mshv/mshv-cpu.c | 117 ++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c
index 8b10c79e547..0fe3cbb48d8 100644
--- a/target/i386/mshv/mshv-cpu.c
+++ b/target/i386/mshv/mshv-cpu.c
@@ -12,6 +12,7 @@
 
 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
+#include "qemu/memalign.h"
 #include "qemu/typedefs.h"
 
 #include "system/mshv.h"
@@ -21,6 +22,7 @@
 #include "hw/hyperv/hvgdk.h"
 #include "hw/hyperv/hvgdk_mini.h"
 #include "hw/hyperv/hvhdk_mini.h"
+#include "hw/i386/apic_internal.h"
 
 #include "cpu.h"
 #include "emulate/x86_decode.h"
@@ -562,6 +564,114 @@ static int set_cpu_state(const CPUState *cpu, const MshvFPU *fpu_regs,
     return 0;
 }
 
+static int get_vp_state(int cpu_fd, struct mshv_get_set_vp_state *state)
+{
+    int ret;
+
+    ret = ioctl(cpu_fd, MSHV_GET_VP_STATE, state);
+    if (ret < 0) {
+        error_report("failed to get partition state: %s", strerror(errno));
+        return -1;
+    }
+
+    return 0;
+}
+
+static int get_lapic(int cpu_fd,
+                     struct hv_local_interrupt_controller_state *state)
+{
+    int ret;
+    size_t size = 4096;
+    /* buffer aligned to 4k, as *state requires that */
+    void *buffer = qemu_memalign(size, size);
+    struct mshv_get_set_vp_state mshv_state = { 0 };
+
+    mshv_state.buf_ptr = (uint64_t) buffer;
+    mshv_state.buf_sz = size;
+    mshv_state.type = MSHV_VP_STATE_LAPIC;
+
+    ret = get_vp_state(cpu_fd, &mshv_state);
+    if (ret == 0) {
+        memcpy(state, buffer, sizeof(*state));
+    }
+    qemu_vfree(buffer);
+    if (ret < 0) {
+        error_report("failed to get lapic");
+        return -1;
+    }
+
+    return 0;
+}
+
+static uint32_t set_apic_delivery_mode(uint32_t reg, uint32_t mode)
+{
+    return ((reg) & ~0x700) | ((mode) << 8);
+}
+
+static int set_vp_state(int cpu_fd, const struct mshv_get_set_vp_state *state)
+{
+    int ret;
+
+    ret = ioctl(cpu_fd, MSHV_SET_VP_STATE, state);
+    if (ret < 0) {
+        error_report("failed to set partition state: %s", strerror(errno));
+        return -1;
+    }
+
+    return 0;
+}
+
+static int set_lapic(int cpu_fd,
+                     const struct hv_local_interrupt_controller_state *state)
+{
+    int ret;
+    size_t size = 4096;
+    /* buffer aligned to 4k, as *state requires that */
+    void *buffer = qemu_memalign(size, size);
+    struct mshv_get_set_vp_state mshv_state = { 0 };
+
+    if (!state) {
+        error_report("lapic state is NULL");
+        return -1;
+    }
+    memcpy(buffer, state, sizeof(*state));
+
+    mshv_state.buf_ptr = (uint64_t) buffer;
+    mshv_state.buf_sz = size;
+    mshv_state.type = MSHV_VP_STATE_LAPIC;
+
+    ret = set_vp_state(cpu_fd, &mshv_state);
+    qemu_vfree(buffer);
+    if (ret < 0) {
+        error_report("failed to set lapic: %s", strerror(errno));
+        return -1;
+    }
+
+    return 0;
+}
+
+static int set_lint(int cpu_fd)
+{
+    int ret;
+    uint32_t *lvt_lint0, *lvt_lint1;
+
+    struct hv_local_interrupt_controller_state lapic_state = { 0 };
+    ret = get_lapic(cpu_fd, &lapic_state);
+    if (ret < 0) {
+        return ret;
+    }
+
+    lvt_lint0 = &lapic_state.apic_lvt_lint0;
+    *lvt_lint0 = set_apic_delivery_mode(*lvt_lint0, APIC_DM_EXTINT);
+
+    lvt_lint1 = &lapic_state.apic_lvt_lint1;
+    *lvt_lint1 = set_apic_delivery_mode(*lvt_lint1, APIC_DM_NMI);
+
+    /* TODO: should we skip setting lapic if the values are the same? */
+
+    return set_lapic(cpu_fd, &lapic_state);
+}
+
 /*
  * TODO: populate topology info:
  *
@@ -573,6 +683,7 @@ int mshv_configure_vcpu(const CPUState *cpu, const struct MshvFPU *fpu,
                         uint64_t xcr0)
 {
     int ret;
+    int cpu_fd = mshv_vcpufd(cpu);
 
     ret = set_cpu_state(cpu, fpu, xcr0);
     if (ret < 0) {
@@ -580,6 +691,12 @@ int mshv_configure_vcpu(const CPUState *cpu, const struct MshvFPU *fpu,
         return -1;
     }
 
+    ret = set_lint(cpu_fd);
+    if (ret < 0) {
+        error_report("failed to set lpic int");
+        return -1;
+    }
+
     return 0;
 }
 
-- 
2.51.0