Re: [PATCH] intel_iommu: Fix invalidation descriptor type field

[Yi Liu]

On 2024/8/13 13:53, Zhenzhong Duan wrote:
> According to spec, invalidation descriptor type is 7bits which is
> concatenation of bits[11:9] and bits[3:0] of invalidation descriptor.
>
> Currently we only pick bits[3:0] as the invalidation type and treat
> bits[11:9] as reserved zero. This is not a problem for now as bits[11:9]
> is zero for all current invalidation types. But it will break if newer
> type occupies bits[11:9].
>
> Fix it by take bits[11:9] into type and make reserved bits check accurate.

s/take/taking/

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

There is another fix you may add. In vtd_process_inv_desc(), it should
treat the type VTD_INV_DESC_PC and VTD_INV_DESC_PIOTLB as invalid type
if vIOMMU is running in legacy mode.

> Suggested-by: Clément Mathieu--Drif<clement.mathieu--drif@eviden.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
> Tested intel-iommu.flat in kvm-unit-test: PASS
> Tested vfio device hotplug: PASS
> ---
>   hw/i386/intel_iommu_internal.h | 11 ++++++-----
>   hw/i386/intel_iommu.c          |  2 +-
>   2 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 5f32c36943..13d5d129ae 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -356,7 +356,8 @@ union VTDInvDesc {
>   typedef union VTDInvDesc VTDInvDesc;
>   
>   /* Masks for struct VTDInvDesc */
> -#define VTD_INV_DESC_TYPE               0xf
> +#define VTD_INV_DESC_TYPE(val)          ((((val) >> 5) & 0x70ULL) | \
> +                                         ((val) & 0xfULL))
>   #define VTD_INV_DESC_CC                 0x1 /* Context-cache Invalidate Desc 
> */
>   #define VTD_INV_DESC_IOTLB              0x2
>   #define VTD_INV_DESC_DEVICE             0x3
> @@ -372,7 +373,7 @@ typedef union VTDInvDesc VTDInvDesc;
>   #define VTD_INV_DESC_WAIT_IF            (1ULL << 4)
>   #define VTD_INV_DESC_WAIT_FN            (1ULL << 6)
>   #define VTD_INV_DESC_WAIT_DATA_SHIFT    32
> -#define VTD_INV_DESC_WAIT_RSVD_LO       0Xffffff80ULL
> +#define VTD_INV_DESC_WAIT_RSVD_LO       0Xfffff180ULL
>   #define VTD_INV_DESC_WAIT_RSVD_HI       3ULL
>   
>   /* Masks for Context-cache Invalidation Descriptor */
> @@ -383,7 +384,7 @@ typedef union VTDInvDesc VTDInvDesc;
>   #define VTD_INV_DESC_CC_DID(val)        (((val) >> 16) & VTD_DOMAIN_ID_MASK)
>   #define VTD_INV_DESC_CC_SID(val)        (((val) >> 32) & 0xffffUL)
>   #define VTD_INV_DESC_CC_FM(val)         (((val) >> 48) & 3UL)
> -#define VTD_INV_DESC_CC_RSVD            0xfffc00000000ffc0ULL
> +#define VTD_INV_DESC_CC_RSVD            0xfffc00000000f1c0ULL
>   
>   /* Masks for IOTLB Invalidate Descriptor */
>   #define VTD_INV_DESC_IOTLB_G            (3ULL << 4)
> @@ -393,7 +394,7 @@ typedef union VTDInvDesc VTDInvDesc;
>   #define VTD_INV_DESC_IOTLB_DID(val)     (((val) >> 16) & VTD_DOMAIN_ID_MASK)
>   #define VTD_INV_DESC_IOTLB_ADDR(val)    ((val) & ~0xfffULL)
>   #define VTD_INV_DESC_IOTLB_AM(val)      ((val) & 0x3fULL)
> -#define VTD_INV_DESC_IOTLB_RSVD_LO      0xffffffff0000ff00ULL
> +#define VTD_INV_DESC_IOTLB_RSVD_LO      0xffffffff0000f100ULL
>   #define VTD_INV_DESC_IOTLB_RSVD_HI      0xf80ULL
>   #define VTD_INV_DESC_IOTLB_PASID_PASID  (2ULL << 4)
>   #define VTD_INV_DESC_IOTLB_PASID_PAGE   (3ULL << 4)
> @@ -406,7 +407,7 @@ typedef union VTDInvDesc VTDInvDesc;
>   #define VTD_INV_DESC_DEVICE_IOTLB_SIZE(val) ((val) & 0x1)
>   #define VTD_INV_DESC_DEVICE_IOTLB_SID(val) (((val) >> 32) & 0xFFFFULL)
>   #define VTD_INV_DESC_DEVICE_IOTLB_RSVD_HI 0xffeULL
> -#define VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO 0xffff0000ffe0fff8
> +#define VTD_INV_DESC_DEVICE_IOTLB_RSVD_LO 0xffff0000ffe0f1f0
>   
>   /* Rsvd field masks for spte */
>   #define VTD_SPTE_SNP 0x800ULL
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 16d2885fcc..68cb72a481 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -2744,7 +2744,7 @@ static bool vtd_process_inv_desc(IntelIOMMUState *s)
>           return false;
>       }
>   
> -    desc_type = inv_desc.lo & VTD_INV_DESC_TYPE;
> +    desc_type = VTD_INV_DESC_TYPE(inv_desc.lo);
>       /* FIXME: should update at first or at last? */
>       s->iq_last_desc_type = desc_type;
>   

--
Regards,
Yi Liu