RE: [PATCH V10 09/11] iommu/vt-d: Cache virtual command capability register

Tian, Kevin
2020-03-28T10:04:57Z

> From: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Sent: Saturday, March 21, 2020 7:28 AM
>
> Virtual command registers are used in the guest only, to prevent
> vmexit cost, we cache the capability and store it during initialization.
>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
>
> ---
> v7 Reviewed by Eric & Baolu
> ---
> ---
> drivers/iommu/dmar.c | 1 +
> include/linux/intel-iommu.h | 5 +++++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 4d6b7b5b37ee..3b36491c8bbb 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -963,6 +963,7 @@ static int map_iommu(struct intel_iommu *iommu,
> u64 phys_addr)
> warn_invalid_dmar(phys_addr, " returns all ones");
> goto unmap;
> }
> + iommu->vccap = dmar_readq(iommu->reg + DMAR_VCCAP_REG);
>
> /* the registers might be more than one page */
> map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap),
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 43539713b3b3..ccbf164fb711 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -194,6 +194,9 @@
> #define ecap_max_handle_mask(e) ((e >> 20) & 0xf)
> #define ecap_sc_support(e) ((e >> 7) & 0x1) /* Snooping Control */
>
> +/* Virtual command interface capabilities */

capabilities -> capability

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

> +#define vccap_pasid(v) ((v & DMA_VCS_PAS)) /* PASID
> allocation */
> +
> /* IOTLB_REG */
> #define DMA_TLB_FLUSH_GRANU_OFFSET 60
> #define DMA_TLB_GLOBAL_FLUSH (((u64)1) << 60)
> @@ -287,6 +290,7 @@
>
> /* PRS_REG */
> #define DMA_PRS_PPR ((u32)1)
> +#define DMA_VCS_PAS ((u64)1)
>
> #define IOMMU_WAIT_OP(iommu, offset, op, cond, sts)
> \
> do { \
> @@ -537,6 +541,7 @@ struct intel_iommu {
> u64 reg_size; /* size of hw register set */
> u64 cap;
> u64 ecap;
> + u64 vccap;
> u32 gcmd; /* Holds TE, EAFL. Don't need SRTP, SFL, WBF
> */
> raw_spinlock_t register_lock; /* protect register handling */
> int seq_id; /* sequence id of the iommu */
> --
> 2.7.4