In early days, we have different tricks to ensure caching-mode=on with VFIO
device:
28cf553afe ("intel_iommu: Sanity check vfio-pci config on machine init done")
c6cbc29d36 ("pc/q35: Disallow vfio-pci hotplug without VT-d caching mode")
b8d78277c0 ("intel-iommu: fail MAP notifier without caching mode")
Because without caching mode, MAP notifier won't work correctly since guest
won't send IOTLB update event when it establishes new mappings in the I/O page
tables.
Now with host IOMMU device interface between VFIO and vIOMMU, we can simplify
it with a small check in set_iommu_device(). This also works for future VDPA
implementation which may also need caching mode on.
For coldplug VFIO device:
qemu-system-x86_64: -device vfio-pci,host=0000:3b:00.0,id=hostdev3,bus=root0,iommufd=iommufd0: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed without enabling caching-mode=on for Intel IOMMU.
For hotplug VFIO device:
Error: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed without enabling caching-mode=on for Intel IOMMU.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
hw/i386/intel_iommu.c | 47 ++++++-------------------------------------
hw/i386/pc.c | 20 ------------------
2 files changed, 6 insertions(+), 61 deletions(-)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index f04300022e..5c67b42dde 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -85,13 +85,6 @@ struct vtd_iotlb_key {
static void vtd_address_space_refresh_all(IntelIOMMUState *s);
static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n);
-static void vtd_panic_require_caching_mode(void)
-{
- error_report("We need to set caching-mode=on for intel-iommu to enable "
- "device assignment with IOMMU protection.");
- exit(1);
-}
-
static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val,
uint64_t wmask, uint64_t w1cmask)
{
@@ -3731,13 +3724,6 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
"Snoop Control with vhost or VFIO is not supported");
return -ENOTSUP;
}
- if (!s->caching_mode && (new & IOMMU_NOTIFIER_MAP)) {
- error_setg_errno(errp, ENOTSUP,
- "device %02x.%02x.%x requires caching mode",
- pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
- PCI_FUNC(vtd_as->devfn));
- return -ENOTSUP;
- }
if (!x86_iommu->dt_supported && (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
error_setg_errno(errp, ENOTSUP,
"device %02x.%02x.%x requires device IOTLB mode",
@@ -4378,6 +4364,12 @@ static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
assert(hiod);
+ if (!s->caching_mode) {
+ error_setg(errp, "Device assignment is not allowed without enabling "
+ "caching-mode=on for Intel IOMMU.");
+ return false;
+ }
+
vtd_iommu_lock(s);
if (g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) {
@@ -4910,32 +4902,6 @@ static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
return true;
}
-static int vtd_machine_done_notify_one(Object *child, void *unused)
-{
- IntelIOMMUState *iommu = INTEL_IOMMU_DEVICE(x86_iommu_get_default());
-
- /*
- * We hard-coded here because vfio-pci is the only special case
- * here. Let's be more elegant in the future when we can, but so
- * far there seems to be no better way.
- */
- if (object_dynamic_cast(child, "vfio-pci") && !iommu->caching_mode) {
- vtd_panic_require_caching_mode();
- }
-
- return 0;
-}
-
-static void vtd_machine_done_hook(Notifier *notifier, void *unused)
-{
- object_child_foreach_recursive(object_get_root(),
- vtd_machine_done_notify_one, NULL);
-}
-
-static Notifier vtd_machine_done_notify = {
- .notify = vtd_machine_done_hook,
-};
-
static void vtd_realize(DeviceState *dev, Error **errp)
{
MachineState *ms = MACHINE(qdev_get_machine());
@@ -4990,7 +4956,6 @@ static void vtd_realize(DeviceState *dev, Error **errp)
pci_setup_iommu(bus, &vtd_iommu_ops, dev);
/* Pseudo address space under root PCI bus. */
x86ms->ioapic_as = vtd_host_dma_iommu(bus, s, Q35_PSEUDO_DEVFN_IOAPIC);
- qemu_add_machine_init_done_notifier(&vtd_machine_done_notify);
}
static void vtd_class_init(ObjectClass *klass, const void *data)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index bc048a6d13..01cd9a67db 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1720,25 +1720,6 @@ static void pc_machine_wakeup(MachineState *machine)
cpu_synchronize_all_post_reset();
}
-static bool pc_hotplug_allowed(MachineState *ms, DeviceState *dev, Error **errp)
-{
- X86IOMMUState *iommu = x86_iommu_get_default();
- IntelIOMMUState *intel_iommu;
-
- if (iommu &&
- object_dynamic_cast((Object *)iommu, TYPE_INTEL_IOMMU_DEVICE) &&
- object_dynamic_cast((Object *)dev, "vfio-pci")) {
- intel_iommu = INTEL_IOMMU_DEVICE(iommu);
- if (!intel_iommu->caching_mode) {
- error_setg(errp, "Device assignment is not allowed without "
- "enabling caching-mode=on for Intel IOMMU.");
- return false;
- }
- }
-
- return true;
-}
-
static void pc_machine_class_init(ObjectClass *oc, const void *data)
{
MachineClass *mc = MACHINE_CLASS(oc);
@@ -1758,7 +1739,6 @@ static void pc_machine_class_init(ObjectClass *oc, const void *data)
x86mc->apic_xrupt_override = true;
assert(!mc->get_hotplug_handler);
mc->get_hotplug_handler = pc_get_hotplug_handler;
- mc->hotplug_allowed = pc_hotplug_allowed;
mc->auto_enable_numa_with_memhp = true;
mc->auto_enable_numa_with_memdev = true;
mc->has_hotpluggable_cpus = true;
--
2.47.1
>-----Original Message-----
>From: Duan, Zhenzhong <zhenzhong.duan@intel.com>
>Subject: [PATCH 2/2] intel_iommu: Simplify caching mode check with VFIO
>device
>
>In early days, we have different tricks to ensure caching-mode=on with VFIO
>device:
>
>28cf553afe ("intel_iommu: Sanity check vfio-pci config on machine init done")
>c6cbc29d36 ("pc/q35: Disallow vfio-pci hotplug without VT-d caching mode")
>b8d78277c0 ("intel-iommu: fail MAP notifier without caching mode")
>
>Because without caching mode, MAP notifier won't work correctly since
>guest
>won't send IOTLB update event when it establishes new mappings in the I/O
>page
>tables.
>
>Now with host IOMMU device interface between VFIO and vIOMMU, we can
>simplify
>it with a small check in set_iommu_device(). This also works for future VDPA
>implementation which may also need caching mode on.
I made a wrong assumption on VDPA, currently VDPA doesn't use hiod interface,
so commit b8d78277c0 is still needed for VDPA. I'll have to send a v2, sorry for noise.
BRs,
Zhenzhong
>
>For coldplug VFIO device:
>
>qemu-system-x86_64: -device
>vfio-pci,host=0000:3b:00.0,id=hostdev3,bus=root0,iommufd=iommufd0: vfio
>0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed
>without enabling caching-mode=on for Intel IOMMU.
>
>For hotplug VFIO device:
>
>Error: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not
>allowed without enabling caching-mode=on for Intel IOMMU.
>
>Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>---
> hw/i386/intel_iommu.c | 47 ++++++-------------------------------------
> hw/i386/pc.c | 20 ------------------
> 2 files changed, 6 insertions(+), 61 deletions(-)
>
>diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
>index f04300022e..5c67b42dde 100644
>--- a/hw/i386/intel_iommu.c
>+++ b/hw/i386/intel_iommu.c
>@@ -85,13 +85,6 @@ struct vtd_iotlb_key {
> static void vtd_address_space_refresh_all(IntelIOMMUState *s);
> static void vtd_address_space_unmap(VTDAddressSpace *as,
>IOMMUNotifier *n);
>
>-static void vtd_panic_require_caching_mode(void)
>-{
>- error_report("We need to set caching-mode=on for intel-iommu to
>enable "
>- "device assignment with IOMMU protection.");
>- exit(1);
>-}
>-
> static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val,
> uint64_t wmask, uint64_t w1cmask)
> {
>@@ -3731,13 +3724,6 @@ static int
>vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
> "Snoop Control with vhost or VFIO is not
>supported");
> return -ENOTSUP;
> }
>- if (!s->caching_mode && (new & IOMMU_NOTIFIER_MAP)) {
>- error_setg_errno(errp, ENOTSUP,
>- "device %02x.%02x.%x requires caching
>mode",
>- pci_bus_num(vtd_as->bus),
>PCI_SLOT(vtd_as->devfn),
>- PCI_FUNC(vtd_as->devfn));
>- return -ENOTSUP;
>- }
> if (!x86_iommu->dt_supported && (new &
>IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
> error_setg_errno(errp, ENOTSUP,
> "device %02x.%02x.%x requires device IOTLB
>mode",
>@@ -4378,6 +4364,12 @@ static bool vtd_dev_set_iommu_device(PCIBus
>*bus, void *opaque, int devfn,
>
> assert(hiod);
>
>+ if (!s->caching_mode) {
>+ error_setg(errp, "Device assignment is not allowed without
>enabling "
>+ "caching-mode=on for Intel IOMMU.");
>+ return false;
>+ }
>+
> vtd_iommu_lock(s);
>
> if (g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) {
>@@ -4910,32 +4902,6 @@ static bool vtd_decide_config(IntelIOMMUState
>*s, Error **errp)
> return true;
> }
>
>-static int vtd_machine_done_notify_one(Object *child, void *unused)
>-{
>- IntelIOMMUState *iommu =
>INTEL_IOMMU_DEVICE(x86_iommu_get_default());
>-
>- /*
>- * We hard-coded here because vfio-pci is the only special case
>- * here. Let's be more elegant in the future when we can, but so
>- * far there seems to be no better way.
>- */
>- if (object_dynamic_cast(child, "vfio-pci") && !iommu->caching_mode) {
>- vtd_panic_require_caching_mode();
>- }
>-
>- return 0;
>-}
>-
>-static void vtd_machine_done_hook(Notifier *notifier, void *unused)
>-{
>- object_child_foreach_recursive(object_get_root(),
>- vtd_machine_done_notify_one,
>NULL);
>-}
>-
>-static Notifier vtd_machine_done_notify = {
>- .notify = vtd_machine_done_hook,
>-};
>-
> static void vtd_realize(DeviceState *dev, Error **errp)
> {
> MachineState *ms = MACHINE(qdev_get_machine());
>@@ -4990,7 +4956,6 @@ static void vtd_realize(DeviceState *dev, Error
>**errp)
> pci_setup_iommu(bus, &vtd_iommu_ops, dev);
> /* Pseudo address space under root PCI bus. */
> x86ms->ioapic_as = vtd_host_dma_iommu(bus, s,
>Q35_PSEUDO_DEVFN_IOAPIC);
>- qemu_add_machine_init_done_notifier(&vtd_machine_done_notify);
> }
>
> static void vtd_class_init(ObjectClass *klass, const void *data)
>diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>index bc048a6d13..01cd9a67db 100644
>--- a/hw/i386/pc.c
>+++ b/hw/i386/pc.c
>@@ -1720,25 +1720,6 @@ static void pc_machine_wakeup(MachineState
>*machine)
> cpu_synchronize_all_post_reset();
> }
>
>-static bool pc_hotplug_allowed(MachineState *ms, DeviceState *dev, Error
>**errp)
>-{
>- X86IOMMUState *iommu = x86_iommu_get_default();
>- IntelIOMMUState *intel_iommu;
>-
>- if (iommu &&
>- object_dynamic_cast((Object *)iommu,
>TYPE_INTEL_IOMMU_DEVICE) &&
>- object_dynamic_cast((Object *)dev, "vfio-pci")) {
>- intel_iommu = INTEL_IOMMU_DEVICE(iommu);
>- if (!intel_iommu->caching_mode) {
>- error_setg(errp, "Device assignment is not allowed without "
>- "enabling caching-mode=on for Intel IOMMU.");
>- return false;
>- }
>- }
>-
>- return true;
>-}
>-
> static void pc_machine_class_init(ObjectClass *oc, const void *data)
> {
> MachineClass *mc = MACHINE_CLASS(oc);
>@@ -1758,7 +1739,6 @@ static void pc_machine_class_init(ObjectClass *oc,
>const void *data)
> x86mc->apic_xrupt_override = true;
> assert(!mc->get_hotplug_handler);
> mc->get_hotplug_handler = pc_get_hotplug_handler;
>- mc->hotplug_allowed = pc_hotplug_allowed;
> mc->auto_enable_numa_with_memhp = true;
> mc->auto_enable_numa_with_memdev = true;
> mc->has_hotpluggable_cpus = true;
>--
>2.47.1
Hi Zhenzhnog,
Nice!
Reviewed-by: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
Thanks
On Fri, 2025-09-19 at 03:06 -0400, Zhenzhong Duan wrote:
> Caution: External email. Do not open attachments or click links, unless this email comes from a known sender and you know the content is safe.
>
>
> In early days, we have different tricks to ensure caching-mode=on with VFIO
> device:
>
> 28cf553afe ("intel_iommu: Sanity check vfio-pci config on machine init done")
> c6cbc29d36 ("pc/q35: Disallow vfio-pci hotplug without VT-d caching mode")
> b8d78277c0 ("intel-iommu: fail MAP notifier without caching mode")
>
> Because without caching mode, MAP notifier won't work correctly since guest
> won't send IOTLB update event when it establishes new mappings in the I/O page
> tables.
>
> Now with host IOMMU device interface between VFIO and vIOMMU, we can simplify
> it with a small check in set_iommu_device(). This also works for future VDPA
> implementation which may also need caching mode on.
>
> For coldplug VFIO device:
>
> qemu-system-x86_64: -device vfio-pci,host=0000:3b:00.0,id=hostdev3,bus=root0,iommufd=iommufd0: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed without enabling caching-mode=on for Intel IOMMU.
>
> For hotplug VFIO device:
>
> Error: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed without enabling caching-mode=on for Intel IOMMU.
>
> Signed-off-by: Zhenzhong Duan <[zhenzhong.duan@intel.com](mailto:zhenzhong.duan@intel.com)>
> ---
> hw/i386/intel_iommu.c | 47 ++++++-------------------------------------
> hw/i386/pc.c | 20 ------------------
> 2 files changed, 6 insertions(+), 61 deletions(-)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index f04300022e..5c67b42dde 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -85,13 +85,6 @@ struct vtd_iotlb_key {
> static void vtd_address_space_refresh_all(IntelIOMMUState *s);
> static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n);
>
> -static void vtd_panic_require_caching_mode(void)
> -{
> - error_report("We need to set caching-mode=on for intel-iommu to enable "
> - "device assignment with IOMMU protection.");
> - exit(1);
> -}
> -
> static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val,
> uint64_t wmask, uint64_t w1cmask)
> {
> @@ -3731,13 +3724,6 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
> "Snoop Control with vhost or VFIO is not supported");
> return -ENOTSUP;
> }
> - if (!s->caching_mode && (new & IOMMU_NOTIFIER_MAP)) {
> - error_setg_errno(errp, ENOTSUP,
> - "device %02x.%02x.%x requires caching mode",
> - pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
> - PCI_FUNC(vtd_as->devfn));
> - return -ENOTSUP;
> - }
> if (!x86_iommu->dt_supported && (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
> error_setg_errno(errp, ENOTSUP,
> "device %02x.%02x.%x requires device IOTLB mode",
> @@ -4378,6 +4364,12 @@ static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
>
> assert(hiod);
>
> + if (!s->caching_mode) {
> + error_setg(errp, "Device assignment is not allowed without enabling "
> + "caching-mode=on for Intel IOMMU.");
> + return false;
> + }
> +
> vtd_iommu_lock(s);
>
> if (g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) {
> @@ -4910,32 +4902,6 @@ static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
> return true;
> }
>
> -static int vtd_machine_done_notify_one(Object *child, void *unused)
> -{
> - IntelIOMMUState *iommu = INTEL_IOMMU_DEVICE(x86_iommu_get_default());
> -
> - /*
> - * We hard-coded here because vfio-pci is the only special case
> - * here. Let's be more elegant in the future when we can, but so
> - * far there seems to be no better way.
> - */
> - if (object_dynamic_cast(child, "vfio-pci") && !iommu->caching_mode) {
> - vtd_panic_require_caching_mode();
> - }
> -
> - return 0;
> -}
> -
> -static void vtd_machine_done_hook(Notifier *notifier, void *unused)
> -{
> - object_child_foreach_recursive(object_get_root(),
> - vtd_machine_done_notify_one, NULL);
> -}
> -
> -static Notifier vtd_machine_done_notify = {
> - .notify = vtd_machine_done_hook,
> -};
> -
> static void vtd_realize(DeviceState *dev, Error **errp)
> {
> MachineState *ms = MACHINE(qdev_get_machine());
> @@ -4990,7 +4956,6 @@ static void vtd_realize(DeviceState *dev, Error **errp)
> pci_setup_iommu(bus, &vtd_iommu_ops, dev);
> /* Pseudo address space under root PCI bus. */
> x86ms->ioapic_as = vtd_host_dma_iommu(bus, s, Q35_PSEUDO_DEVFN_IOAPIC);
> - qemu_add_machine_init_done_notifier(&vtd_machine_done_notify);
> }
>
> static void vtd_class_init(ObjectClass *klass, const void *data)
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index bc048a6d13..01cd9a67db 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1720,25 +1720,6 @@ static void pc_machine_wakeup(MachineState *machine)
> cpu_synchronize_all_post_reset();
> }
>
> -static bool pc_hotplug_allowed(MachineState *ms, DeviceState *dev, Error **errp)
> -{
> - X86IOMMUState *iommu = x86_iommu_get_default();
> - IntelIOMMUState *intel_iommu;
> -
> - if (iommu &&
> - object_dynamic_cast((Object *)iommu, TYPE_INTEL_IOMMU_DEVICE) &&
> - object_dynamic_cast((Object *)dev, "vfio-pci")) {
> - intel_iommu = INTEL_IOMMU_DEVICE(iommu);
> - if (!intel_iommu->caching_mode) {
> - error_setg(errp, "Device assignment is not allowed without "
> - "enabling caching-mode=on for Intel IOMMU.");
> - return false;
> - }
> - }
> -
> - return true;
> -}
> -
> static void pc_machine_class_init(ObjectClass *oc, const void *data)
> {
> MachineClass *mc = MACHINE_CLASS(oc);
> @@ -1758,7 +1739,6 @@ static void pc_machine_class_init(ObjectClass *oc, const void *data)
> x86mc->apic_xrupt_override = true;
> assert(!mc->get_hotplug_handler);
> mc->get_hotplug_handler = pc_get_hotplug_handler;
> - mc->hotplug_allowed = pc_hotplug_allowed;
> mc->auto_enable_numa_with_memhp = true;
> mc->auto_enable_numa_with_memdev = true;
> mc->has_hotpluggable_cpus = true;
> --
> 2.47.1
>
On 9/19/25 09:06, Zhenzhong Duan wrote:
> In early days, we have different tricks to ensure caching-mode=on with VFIO
> device:
>
> 28cf553afe ("intel_iommu: Sanity check vfio-pci config on machine init done")
> c6cbc29d36 ("pc/q35: Disallow vfio-pci hotplug without VT-d caching mode")
> b8d78277c0 ("intel-iommu: fail MAP notifier without caching mode")
>
> Because without caching mode, MAP notifier won't work correctly since guest
> won't send IOTLB update event when it establishes new mappings in the I/O page
> tables.
>
> Now with host IOMMU device interface between VFIO and vIOMMU, we can simplify
> it with a small check in set_iommu_device(). This also works for future VDPA
> implementation which may also need caching mode on.
>
> For coldplug VFIO device:
>
> qemu-system-x86_64: -device vfio-pci,host=0000:3b:00.0,id=hostdev3,bus=root0,iommufd=iommufd0: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed without enabling caching-mode=on for Intel IOMMU.
>
> For hotplug VFIO device:
>
> Error: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed without enabling caching-mode=on for Intel IOMMU.
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
> hw/i386/intel_iommu.c | 47 ++++++-------------------------------------
> hw/i386/pc.c | 20 ------------------
> 2 files changed, 6 insertions(+), 61 deletions(-)
This is a nice cleanup.
Acked-by: Cédric Le Goater <clg@redhat.com>
Thanks,
C.
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index f04300022e..5c67b42dde 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -85,13 +85,6 @@ struct vtd_iotlb_key {
> static void vtd_address_space_refresh_all(IntelIOMMUState *s);
> static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n);
>
> -static void vtd_panic_require_caching_mode(void)
> -{
> - error_report("We need to set caching-mode=on for intel-iommu to enable "
> - "device assignment with IOMMU protection.");
> - exit(1);
> -}
> -
> static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val,
> uint64_t wmask, uint64_t w1cmask)
> {
> @@ -3731,13 +3724,6 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
> "Snoop Control with vhost or VFIO is not supported");
> return -ENOTSUP;
> }
> - if (!s->caching_mode && (new & IOMMU_NOTIFIER_MAP)) {
> - error_setg_errno(errp, ENOTSUP,
> - "device %02x.%02x.%x requires caching mode",
> - pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
> - PCI_FUNC(vtd_as->devfn));
> - return -ENOTSUP;
> - }
> if (!x86_iommu->dt_supported && (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
> error_setg_errno(errp, ENOTSUP,
> "device %02x.%02x.%x requires device IOTLB mode",
> @@ -4378,6 +4364,12 @@ static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
>
> assert(hiod);
>
> + if (!s->caching_mode) {
> + error_setg(errp, "Device assignment is not allowed without enabling "
> + "caching-mode=on for Intel IOMMU.");
> + return false;
> + }
> +
> vtd_iommu_lock(s);
>
> if (g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) {
> @@ -4910,32 +4902,6 @@ static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
> return true;
> }
>
> -static int vtd_machine_done_notify_one(Object *child, void *unused)
> -{
> - IntelIOMMUState *iommu = INTEL_IOMMU_DEVICE(x86_iommu_get_default());
> -
> - /*
> - * We hard-coded here because vfio-pci is the only special case
> - * here. Let's be more elegant in the future when we can, but so
> - * far there seems to be no better way.
> - */
> - if (object_dynamic_cast(child, "vfio-pci") && !iommu->caching_mode) {
> - vtd_panic_require_caching_mode();
> - }
> -
> - return 0;
> -}
> -
> -static void vtd_machine_done_hook(Notifier *notifier, void *unused)
> -{
> - object_child_foreach_recursive(object_get_root(),
> - vtd_machine_done_notify_one, NULL);
> -}
> -
> -static Notifier vtd_machine_done_notify = {
> - .notify = vtd_machine_done_hook,
> -};
> -
> static void vtd_realize(DeviceState *dev, Error **errp)
> {
> MachineState *ms = MACHINE(qdev_get_machine());
> @@ -4990,7 +4956,6 @@ static void vtd_realize(DeviceState *dev, Error **errp)
> pci_setup_iommu(bus, &vtd_iommu_ops, dev);
> /* Pseudo address space under root PCI bus. */
> x86ms->ioapic_as = vtd_host_dma_iommu(bus, s, Q35_PSEUDO_DEVFN_IOAPIC);
> - qemu_add_machine_init_done_notifier(&vtd_machine_done_notify);
> }
>
> static void vtd_class_init(ObjectClass *klass, const void *data)
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index bc048a6d13..01cd9a67db 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1720,25 +1720,6 @@ static void pc_machine_wakeup(MachineState *machine)
> cpu_synchronize_all_post_reset();
> }
>
> -static bool pc_hotplug_allowed(MachineState *ms, DeviceState *dev, Error **errp)
> -{
> - X86IOMMUState *iommu = x86_iommu_get_default();
> - IntelIOMMUState *intel_iommu;
> -
> - if (iommu &&
> - object_dynamic_cast((Object *)iommu, TYPE_INTEL_IOMMU_DEVICE) &&
> - object_dynamic_cast((Object *)dev, "vfio-pci")) {
> - intel_iommu = INTEL_IOMMU_DEVICE(iommu);
> - if (!intel_iommu->caching_mode) {
> - error_setg(errp, "Device assignment is not allowed without "
> - "enabling caching-mode=on for Intel IOMMU.");
> - return false;
> - }
> - }
> -
> - return true;
> -}
> -
> static void pc_machine_class_init(ObjectClass *oc, const void *data)
> {
> MachineClass *mc = MACHINE_CLASS(oc);
> @@ -1758,7 +1739,6 @@ static void pc_machine_class_init(ObjectClass *oc, const void *data)
> x86mc->apic_xrupt_override = true;
> assert(!mc->get_hotplug_handler);
> mc->get_hotplug_handler = pc_get_hotplug_handler;
> - mc->hotplug_allowed = pc_hotplug_allowed;
> mc->auto_enable_numa_with_memhp = true;
> mc->auto_enable_numa_with_memdev = true;
> mc->has_hotpluggable_cpus = true;
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