Re: [PATCH v6 06/22] intel_iommu: Implement get_viommu_flags() callback

[Yi Liu <yi.l.liu@intel.com>]

On 2025/9/18 16:57, Zhenzhong Duan wrote:
> Implement get_viommu_flags() callback and expose a request for nesting
> parent HWPT for now.
> 
> VFIO uses it to create nesting parent HWPT which is further used to create
> nested HWPT in vIOMMU. All these will be implemented in following patches.
> 
> 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>
> Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>   hw/i386/intel_iommu.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index a47482ba9d..83c40975cc 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -24,6 +24,7 @@
>   #include "qemu/main-loop.h"
>   #include "qapi/error.h"
>   #include "hw/sysbus.h"
> +#include "hw/iommu.h"
>   #include "intel_iommu_internal.h"
>   #include "hw/pci/pci.h"
>   #include "hw/pci/pci_bus.h"
> @@ -4412,6 +4413,16 @@ static void vtd_dev_unset_iommu_device(PCIBus *bus, void *opaque, int devfn)
>       vtd_iommu_unlock(s);
>   }
>   
> +static uint64_t vtd_get_viommu_flags(void *opaque)
> +{
> +    IntelIOMMUState *s = opaque;
> +    uint64_t caps;

s/caps/flags

> +
> +    caps = s->fsts ? VIOMMU_FLAG_WANT_NESTING_PARENT : 0;
> +
> +    return caps;
> +}
> +
>   /* Unmap the whole range in the notifier's scope. */
>   static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
>   {
> @@ -4842,6 +4853,7 @@ static PCIIOMMUOps vtd_iommu_ops = {
>       .register_iotlb_notifier = vtd_register_iotlb_notifier,
>       .unregister_iotlb_notifier = vtd_unregister_iotlb_notifier,
>       .ats_request_translation = vtd_ats_request_translation,
> +    .get_viommu_flags = vtd_get_viommu_flags,
>   };
>   
>   static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)

Reviewed-by: Yi Liu <yi.l.liu@intel.com>

Regards,
Yi Liu