From: Michal Privoznik <mprivozn@redhat.com>
Introduced in QEMU commit of v9.0.0-rc0~9^2~7 the virtio-iommu
device is also capable of using different addres width. The
corresponding attribute is also called 'aw-bits', just like in
case of intel-iommu. Wire up the missing pieces.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
docs/formatdomain.rst | 2 +-
src/conf/domain_validate.c | 9 +++++++--
src/qemu/qemu_validate.c | 7 +++++--
.../virtio-iommu-aarch64.aarch64-latest.xml | 1 +
tests/qemuxmlconfdata/virtio-iommu-aarch64.xml | 4 +++-
.../virtio-iommu-dma-translation.x86_64-latest.err | 2 +-
6 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 04ef319a73..4b34a8a963 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -9243,7 +9243,7 @@ Example:
``aw_bits``
The ``aw_bits`` attribute can be used to set the address width to allow
mapping larger iova addresses in the guest. :since:`Since 6.5.0` (QEMU/KVM
- and ``intel`` model only)
+ and ``intel`` or ``virtio`` models only)
``dma_translation``
The ``dma_translation`` attribute with possible values ``on`` and ``off`` can
diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
index 4482203087..440f23d726 100644
--- a/src/conf/domain_validate.c
+++ b/src/conf/domain_validate.c
@@ -3206,14 +3206,19 @@ virDomainIOMMUDefValidate(const virDomainIOMMUDef *iommu)
iommu->caching_mode != VIR_TRISTATE_SWITCH_ABSENT ||
iommu->eim != VIR_TRISTATE_SWITCH_ABSENT ||
iommu->iotlb != VIR_TRISTATE_SWITCH_ABSENT ||
- iommu->aw_bits != 0 ||
iommu->dma_translation != VIR_TRISTATE_SWITCH_ABSENT ||
iommu->pci_bus >= 0) {
virReportError(VIR_ERR_XML_ERROR,
- _("iommu model '%1$s' doesn't support additional attributes"),
+ _("iommu model '%1$s' doesn't support some additional attributes"),
virDomainIOMMUModelTypeToString(iommu->model));
return -1;
}
+
+ if (iommu->aw_bits != 0 && (iommu->aw_bits < 32 || iommu->aw_bits > 64)) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("aw-bits must be within [32,64]"));
+ return -1;
+ }
break;
case VIR_DOMAIN_IOMMU_MODEL_AMD:
diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index 184c23d307..ab8a1938c1 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -5551,6 +5551,8 @@ qemuValidateDomainDeviceDefIOMMU(const virDomainIOMMUDef *iommu,
const virDomainDef *def,
virQEMUCaps *qemuCaps)
{
+ bool aw_bits_supported = false;
+
switch (iommu->model) {
case VIR_DOMAIN_IOMMU_MODEL_INTEL:
if (!qemuDomainIsQ35(def)) {
@@ -5565,6 +5567,7 @@ qemuValidateDomainDeviceDefIOMMU(const virDomainIOMMUDef *iommu,
virDomainIOMMUModelTypeToString(iommu->model));
return -1;
}
+ aw_bits_supported = virQEMUCapsGet(qemuCaps, QEMU_CAPS_INTEL_IOMMU_AW_BITS);
break;
case VIR_DOMAIN_IOMMU_MODEL_SMMUV3:
@@ -5610,6 +5613,7 @@ qemuValidateDomainDeviceDefIOMMU(const virDomainIOMMUDef *iommu,
virDomainIOMMUModelTypeToString(iommu->model));
return -1;
}
+ aw_bits_supported = virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_IOMMU_AW_BITS);
break;
case VIR_DOMAIN_IOMMU_MODEL_AMD:
@@ -5669,8 +5673,7 @@ qemuValidateDomainDeviceDefIOMMU(const virDomainIOMMUDef *iommu,
_("iommu: device IOTLB is not supported with this QEMU binary"));
return -1;
}
- if (iommu->aw_bits > 0 &&
- !virQEMUCapsGet(qemuCaps, QEMU_CAPS_INTEL_IOMMU_AW_BITS)) {
+ if (iommu->aw_bits > 0 && !aw_bits_supported) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("iommu: aw_bits is not supported with this QEMU binary"));
return -1;
diff --git a/tests/qemuxmlconfdata/virtio-iommu-aarch64.aarch64-latest.xml b/tests/qemuxmlconfdata/virtio-iommu-aarch64.aarch64-latest.xml
index 3cb794cbc9..4ae628ab5a 100644
--- a/tests/qemuxmlconfdata/virtio-iommu-aarch64.aarch64-latest.xml
+++ b/tests/qemuxmlconfdata/virtio-iommu-aarch64.aarch64-latest.xml
@@ -29,6 +29,7 @@
<audio id='1' type='none'/>
<memballoon model='none'/>
<iommu model='virtio'>
+ <driver aw_bits='48'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
</iommu>
</devices>
diff --git a/tests/qemuxmlconfdata/virtio-iommu-aarch64.xml b/tests/qemuxmlconfdata/virtio-iommu-aarch64.xml
index 8d252bfcf9..96e5ea05ae 100644
--- a/tests/qemuxmlconfdata/virtio-iommu-aarch64.xml
+++ b/tests/qemuxmlconfdata/virtio-iommu-aarch64.xml
@@ -13,6 +13,8 @@
<emulator>/usr/bin/qemu-system-aarch64</emulator>
<controller type='usb' model='none'/>
<memballoon model='none'/>
- <iommu model='virtio'/>
+ <iommu model='virtio'>
+ <driver aw_bits='48'/>
+ </iommu>
</devices>
</domain>
diff --git a/tests/qemuxmlconfdata/virtio-iommu-dma-translation.x86_64-latest.err b/tests/qemuxmlconfdata/virtio-iommu-dma-translation.x86_64-latest.err
index 2c3a272725..f4405a9b7d 100644
--- a/tests/qemuxmlconfdata/virtio-iommu-dma-translation.x86_64-latest.err
+++ b/tests/qemuxmlconfdata/virtio-iommu-dma-translation.x86_64-latest.err
@@ -1 +1 @@
-XML error: iommu model 'virtio' doesn't support additional attributes
+XML error: iommu model 'virtio' doesn't support some additional attributes
--
2.52.0On Wed, Jan 21, 2026 at 17:27:18 +0100, Michal Privoznik via Devel wrote:
> From: Michal Privoznik <mprivozn@redhat.com>
>
> Introduced in QEMU commit of v9.0.0-rc0~9^2~7 the virtio-iommu
> device is also capable of using different addres width. The
> corresponding attribute is also called 'aw-bits', just like in
> case of intel-iommu. Wire up the missing pieces.
>
> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> ---
> docs/formatdomain.rst | 2 +-
> src/conf/domain_validate.c | 9 +++++++--
> src/qemu/qemu_validate.c | 7 +++++--
> .../virtio-iommu-aarch64.aarch64-latest.xml | 1 +
> tests/qemuxmlconfdata/virtio-iommu-aarch64.xml | 4 +++-
> .../virtio-iommu-dma-translation.x86_64-latest.err | 2 +-
> 6 files changed, 18 insertions(+), 7 deletions(-)
[...]
> diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
> index 4482203087..440f23d726 100644
> --- a/src/conf/domain_validate.c
> +++ b/src/conf/domain_validate.c
> @@ -3206,14 +3206,19 @@ virDomainIOMMUDefValidate(const virDomainIOMMUDef *iommu)
> iommu->caching_mode != VIR_TRISTATE_SWITCH_ABSENT ||
> iommu->eim != VIR_TRISTATE_SWITCH_ABSENT ||
> iommu->iotlb != VIR_TRISTATE_SWITCH_ABSENT ||
> - iommu->aw_bits != 0 ||
> iommu->dma_translation != VIR_TRISTATE_SWITCH_ABSENT ||
> iommu->pci_bus >= 0) {
> virReportError(VIR_ERR_XML_ERROR,
> - _("iommu model '%1$s' doesn't support additional attributes"),
> + _("iommu model '%1$s' doesn't support some additional attributes"),
> virDomainIOMMUModelTypeToString(iommu->model));
> return -1;
> }
> +
Do you have any justification that you could put into a comment here for
the values?
> + if (iommu->aw_bits != 0 && (iommu->aw_bits < 32 || iommu->aw_bits > 64)) {
> + virReportError(VIR_ERR_XML_ERROR, "%s",
> + _("aw-bits must be within [32,64]"));
> + return -1;
> + }
> break;
On 1/21/26 17:57, Peter Krempa wrote:
> On Wed, Jan 21, 2026 at 17:27:18 +0100, Michal Privoznik via Devel wrote:
>> From: Michal Privoznik <mprivozn@redhat.com>
>>
>> Introduced in QEMU commit of v9.0.0-rc0~9^2~7 the virtio-iommu
>> device is also capable of using different addres width. The
>> corresponding attribute is also called 'aw-bits', just like in
>> case of intel-iommu. Wire up the missing pieces.
>>
>> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
>> ---
>> docs/formatdomain.rst | 2 +-
>> src/conf/domain_validate.c | 9 +++++++--
>> src/qemu/qemu_validate.c | 7 +++++--
>> .../virtio-iommu-aarch64.aarch64-latest.xml | 1 +
>> tests/qemuxmlconfdata/virtio-iommu-aarch64.xml | 4 +++-
>> .../virtio-iommu-dma-translation.x86_64-latest.err | 2 +-
>> 6 files changed, 18 insertions(+), 7 deletions(-)
>
> [...]
>
>
>> diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
>> index 4482203087..440f23d726 100644
>> --- a/src/conf/domain_validate.c
>> +++ b/src/conf/domain_validate.c
>> @@ -3206,14 +3206,19 @@ virDomainIOMMUDefValidate(const virDomainIOMMUDef *iommu)
>> iommu->caching_mode != VIR_TRISTATE_SWITCH_ABSENT ||
>> iommu->eim != VIR_TRISTATE_SWITCH_ABSENT ||
>> iommu->iotlb != VIR_TRISTATE_SWITCH_ABSENT ||
>> - iommu->aw_bits != 0 ||
>> iommu->dma_translation != VIR_TRISTATE_SWITCH_ABSENT ||
>> iommu->pci_bus >= 0) {
>> virReportError(VIR_ERR_XML_ERROR,
>> - _("iommu model '%1$s' doesn't support additional attributes"),
>> + _("iommu model '%1$s' doesn't support some additional attributes"),
>> virDomainIOMMUModelTypeToString(iommu->model));
>> return -1;
>> }
>> +
>
> Do you have any justification that you could put into a comment here for
> the values?
You mean like what values are allowed and which aren't?
Michal
On Thu, Jan 22, 2026 at 12:01:03 +0100, Michal Prívozník wrote:
> On 1/21/26 17:57, Peter Krempa wrote:
> > On Wed, Jan 21, 2026 at 17:27:18 +0100, Michal Privoznik via Devel wrote:
> >> From: Michal Privoznik <mprivozn@redhat.com>
> >>
> >> Introduced in QEMU commit of v9.0.0-rc0~9^2~7 the virtio-iommu
> >> device is also capable of using different addres width. The
> >> corresponding attribute is also called 'aw-bits', just like in
> >> case of intel-iommu. Wire up the missing pieces.
> >>
> >> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> >> ---
> >> docs/formatdomain.rst | 2 +-
> >> src/conf/domain_validate.c | 9 +++++++--
> >> src/qemu/qemu_validate.c | 7 +++++--
> >> .../virtio-iommu-aarch64.aarch64-latest.xml | 1 +
> >> tests/qemuxmlconfdata/virtio-iommu-aarch64.xml | 4 +++-
> >> .../virtio-iommu-dma-translation.x86_64-latest.err | 2 +-
> >> 6 files changed, 18 insertions(+), 7 deletions(-)
> >
> > [...]
> >
> >
> >> diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
> >> index 4482203087..440f23d726 100644
> >> --- a/src/conf/domain_validate.c
> >> +++ b/src/conf/domain_validate.c
> >> @@ -3206,14 +3206,19 @@ virDomainIOMMUDefValidate(const virDomainIOMMUDef *iommu)
> >> iommu->caching_mode != VIR_TRISTATE_SWITCH_ABSENT ||
> >> iommu->eim != VIR_TRISTATE_SWITCH_ABSENT ||
> >> iommu->iotlb != VIR_TRISTATE_SWITCH_ABSENT ||
> >> - iommu->aw_bits != 0 ||
> >> iommu->dma_translation != VIR_TRISTATE_SWITCH_ABSENT ||
> >> iommu->pci_bus >= 0) {
> >> virReportError(VIR_ERR_XML_ERROR,
> >> - _("iommu model '%1$s' doesn't support additional attributes"),
> >> + _("iommu model '%1$s' doesn't support some additional attributes"),
> >> virDomainIOMMUModelTypeToString(iommu->model));
> >> return -1;
> >> }
> >> +
> >
> > Do you have any justification that you could put into a comment here for
> > the values?
>
> You mean like what values are allowed and which aren't?
Sorry I've misplaced my comment. I wanted to know why the range is
between 32 and 64 (inclusive), since it's magic constants. If you have
some reasoning you could use there please add it as a comment
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