Re: [Qemu-devel] [PATCH v3 1/3] IOMMU: add VTD_CAP_CM to vIOMMU capability exposed to guest

[Jason Wang <jasowang@redhat.com>]

On 2016年05月22日 00:19, Aviv B.D wrote:
> From: "Aviv Ben-David" <bd.aviv@gmail.com>
>
> This flag tells the guest to invalidate tlb cache also after unmap operations.
>
> Signed-off-by: Aviv Ben-David <bd.aviv@gmail.com>
> ---

Is this a guest visible behavior?  If yes, shouldn't we cache 
translation fault conditions in IOTLB?

>   hw/i386/intel_iommu.c          | 3 ++-
>   hw/i386/intel_iommu_internal.h | 1 +
>   2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 347718f..1af8da8 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -1949,7 +1949,8 @@ static void vtd_init(IntelIOMMUState *s)
>       s->iq_last_desc_type = VTD_INV_DESC_NONE;
>       s->next_frcd_reg = 0;
>       s->cap = VTD_CAP_FRO | VTD_CAP_NFR | VTD_CAP_ND | VTD_CAP_MGAW |
> -             VTD_CAP_SAGAW | VTD_CAP_MAMV | VTD_CAP_PSI | VTD_CAP_SLLPS;
> +             VTD_CAP_SAGAW | VTD_CAP_MAMV | VTD_CAP_PSI | VTD_CAP_SLLPS |
> +             VTD_CAP_CM;
>       s->ecap = VTD_ECAP_QI | VTD_ECAP_IRO;
>   
>       vtd_reset_context_cache(s);
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index e5f514c..ae40f73 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -190,6 +190,7 @@
>   #define VTD_CAP_MAMV                (VTD_MAMV << 48)
>   #define VTD_CAP_PSI                 (1ULL << 39)
>   #define VTD_CAP_SLLPS               ((1ULL << 34) | (1ULL << 35))
> +#define VTD_CAP_CM                  (1ULL << 7)
>   
>   /* Supported Adjusted Guest Address Widths */
>   #define VTD_CAP_SAGAW_SHIFT         8