Re: [PATCH v4 02/12] vfio/iommufd: Don't initialize nor set a HOST_IOMMU_DEVICE with mdev

[Cédric Le Goater]

On 7/12/24 13:46, Joao Martins wrote:
> mdevs aren't "physical" devices and when asking for backing IOMMU info, it
> fails the entire provisioning of the guest. Fix that by skipping
> HostIOMMUDevice initialization in the presence of mdevs, and skip setting
> an iommu device when it is known to be an mdev.
>
> Cc: Zhenzhong Duan <zhenzhong.duan@intel.com>
> Fixes: 930589520128 ("vfio/iommufd: Implement HostIOMMUDeviceClass::realize() 
> handler")
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>   hw/vfio/common.c |  4 ++++
>   hw/vfio/pci.c    | 10 +++++++---
>   2 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 7cdb969fd396..b0beed44116e 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -1556,6 +1556,10 @@ bool vfio_attach_device(char *name, VFIODevice *vbasedev,
>           return false;
>       }
>   
> +    if (vbasedev->mdev) {
> +        return true;
> +    }
> +
>       hiod = HOST_IOMMU_DEVICE(object_new(ops->hiod_typename));
>       if (!HOST_IOMMU_DEVICE_GET_CLASS(hiod)->realize(hiod, vbasedev, errp)) {
>           object_unref(hiod);
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 585f23a18406..3fc72e898a25 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -3116,7 +3116,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>   
>       vfio_bars_register(vdev);
>   
> -    if (!pci_device_set_iommu_device(pdev, vbasedev->hiod, errp)) {
> +    if (!is_mdev && !pci_device_set_iommu_device(pdev, vbasedev->hiod, errp)) {

let's use vbasedev->mdev instead.


Thanks,

C.


>           error_prepend(errp, "Failed to set iommu_device: ");
>           goto out_teardown;
>       }
> @@ -3239,7 +3239,9 @@ out_deregister:
>           timer_free(vdev->intx.mmap_timer);
>       }
>   out_unset_idev:
> -    pci_device_unset_iommu_device(pdev);
> +    if (!is_mdev) {
> +        pci_device_unset_iommu_device(pdev);
> +    }
>   out_teardown:
>       vfio_teardown_msi(vdev);
>       vfio_bars_exit(vdev);
> @@ -3284,7 +3286,9 @@ static void vfio_exitfn(PCIDevice *pdev)
>       vfio_pci_disable_rp_atomics(vdev);
>       vfio_bars_exit(vdev);
>       vfio_migration_exit(vbasedev);
> -    pci_device_unset_iommu_device(pdev);
> +    if (!vbasedev->mdev) {
> +        pci_device_unset_iommu_device(pdev);
> +    }
>   }
>   
>   static void vfio_pci_reset(DeviceState *dev)