On 7/30/25 12:55, Duan, Zhenzhong wrote:
>
>
>> -----Original Message-----
>> From: Cédric Le Goater <clg@redhat.com>
>> Subject: Re: [PATCH v4 04/20] vfio/iommufd: Force creating nested parent
>> domain
>>
>> On 7/29/25 11:20, Zhenzhong Duan wrote:
>>> Call pci_device_get_viommu_cap() to get if vIOMMU supports
>> VIOMMU_CAP_HW_NESTED,
>>> if yes, create nested parent domain which could be reused by vIOMMU to
>> create
>>> nested domain.
>>>
>>> It is safe because hw_caps & VIOMMU_CAP_HW_NESTED cannot be set yet
>> because
>>> s->flts is forbidden until we support passthrough device with x-flts=on.
>>>
>>> Suggested-by: Nicolin Chen <nicolinc@nvidia.com>
>>> Suggested-by: Yi Liu <yi.l.liu@intel.com>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>> Reviewed-by: Eric Auger <eric.auger@redhat.com>
>>> ---
>>> hw/vfio/iommufd.c | 14 ++++++++++++++
>>> 1 file changed, 14 insertions(+)
>>>
>>> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
>>> index 48c590b6a9..61a548f13f 100644
>>> --- a/hw/vfio/iommufd.c
>>> +++ b/hw/vfio/iommufd.c
>>> @@ -20,6 +20,7 @@
>>> #include "trace.h"
>>> #include "qapi/error.h"
>>> #include "system/iommufd.h"
>>> +#include "hw/iommu.h"
>>> #include "hw/qdev-core.h"
>>> #include "hw/vfio/vfio-cpr.h"
>>> #include "system/reset.h"
>>> @@ -379,6 +380,19 @@ static bool
>> iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
>>> flags = IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
>>> }
>>>
>>> + /*
>>> + * If vIOMMU supports stage-1 translation, force to create nested
>> parent
>>> + * domain which could be reused by vIOMMU to create nested
>> domain.
>>> + */
>>> + if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
>>> + VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice,
>> vbasedev);
>>> +
>>> + hw_caps = pci_device_get_viommu_cap(&vdev->pdev);
>>> + if (hw_caps & VIOMMU_CAP_HW_NESTED) {
>>> + flags |= IOMMU_HWPT_ALLOC_NEST_PARENT;
>>> + }
>>> + }
>>>
>>
>> Could you please add a wrapper for the above ? Something like :
>>
>> static bool vfio_device_viommu_get_nested(VFIODevice *vbasedev)
>> {
>> if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
>> VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice,
>> vbasedev);
>>
>> return !!(pci_device_get_viommu_cap(&vdev->pdev) &
>> VIOMMU_CAP_HW_NESTED);
>> }
>> return false;
>> }
>>
>> May be this routine belongs to hw/vfio/device.c.
>
> Done, see https://github.com/yiliu1765/qemu/commit/7ce1af90d5c1f418f23c9e397a16a3914b30f09f
>
> I also introduced another wrapper vfio_device_to_vfio_pci(), let me know if you think it's unnecessary, I'll fold it.
It's good to have it if you use it everywhere:
hw/vfio/device.c: if (vbasedev->type != VFIO_DEVICE_TYPE_PCI) {
hw/vfio/container.c: vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
hw/vfio/container.c: vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
hw/vfio/listener.c: if (vbasedev && vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
hw/vfio/listener.c: if (vbasedev->type != VFIO_DEVICE_TYPE_PCI) {
hw/vfio/iommufd.c: if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
hw/vfio/iommufd.c: vbasedev_tmp->type != VFIO_DEVICE_TYPE_PCI) {
So, I would address this cleanup separately.
FYI, We also have this helper :
VFIODevice *vfio_get_vfio_device(Object *obj)
{
if (object_dynamic_cast(obj, TYPE_VFIO_PCI)) {
return &VFIO_PCI_BASE(obj)->vbasedev;
} else {
return NULL;
}
}
Thanks,
C.