Re: [PATCH 8/8] x86-iommu: Fail early if vIOMMU specified after vfio-pci

[Eric Auger <eric.auger@redhat.com>]

Hi Peter,

On 10/21/21 12:42 PM, Peter Xu wrote:
> Scan the pci bus to make sure there's no vfio-pci device attached before vIOMMU
> is realized.
>
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/i386/x86-iommu.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/hw/i386/x86-iommu.c b/hw/i386/x86-iommu.c
> index 86ad03972e..58abce7edc 100644
> --- a/hw/i386/x86-iommu.c
> +++ b/hw/i386/x86-iommu.c
> @@ -21,6 +21,7 @@
>  #include "hw/sysbus.h"
>  #include "hw/i386/x86-iommu.h"
>  #include "hw/qdev-properties.h"
> +#include "hw/vfio/pci.h"
>  #include "hw/i386/pc.h"
>  #include "qapi/error.h"
>  #include "qemu/error-report.h"
> @@ -103,6 +104,16 @@ IommuType x86_iommu_get_type(void)
>      return x86_iommu_default->type;
>  }
>  
> +static void x86_iommu_pci_dev_hook(PCIBus *bus, PCIDevice *dev, void *opaque)
> +{
> +    Error **errp = (Error **)opaque;
> +
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_VFIO_PCI)) {
> +        error_setg(errp, "Device '%s' must be specified before vIOMMUs",
> +                   TYPE_VFIO_PCI);
if there are several VFIO-PCI devices set before the IOMMU, errp may be
overriden
as we do not exit the loop as soon as there is an error I think

Eric
> +    }
> +}
> +
>  static void x86_iommu_realize(DeviceState *dev, Error **errp)
>  {
>      X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(dev);
> @@ -120,6 +131,12 @@ static void x86_iommu_realize(DeviceState *dev, Error **errp)
>          return;
>      }
>  
> +    /* Make sure there's no special device plugged before vIOMMU */
> +    pci_for_each_device_all(x86_iommu_pci_dev_hook, (void *)errp);
> +    if (*errp) {
> +        return;
> +    }
> +
>      /* If the user didn't specify IR, choose a default value for it */
>      if (x86_iommu->intr_supported == ON_OFF_AUTO_AUTO) {
>          x86_iommu->intr_supported = irq_all_kernel ?
> @@ -151,6 +168,7 @@ static Property x86_iommu_properties[] = {
>  static void x86_iommu_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> +
>      dc->realize = x86_iommu_realize;
>      device_class_set_props(dc, x86_iommu_properties);
>  }