RE: [PATCH v7 01/11] iommu/vt-d: Cache virtual command capability register

Tian, Kevin
2019-10-25T06:07:19Z

> From: Jacob Pan [mailto:jacob.jun.pan@linux.intel.com]
> Sent: Friday, October 25, 2019 3:55 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>
> ---
> drivers/iommu/dmar.c | 1 +
> include/linux/intel-iommu.h | 4 ++++
> 2 files changed, 5 insertions(+)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index eecd6a421667..49bb7d76e646 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -950,6 +950,7 @@ 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 ed11ef594378..2e1bed9b7eef 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -186,6 +186,9 @@
> #define ecap_max_handle_mask(e) ((e >> 20) & 0xf)
> #define ecap_sc_support(e) ((e >> 7) & 0x1) /* Snooping Control */
>
> +/* Virtual command interface capabilities */
> +#define vccap_pasid(v) ((v & DMA_VCS_PAS)) /* PASID
> allocation */

DMA_VCS_PAS is defined in [2/11]. should move to here.

> +
> /* IOTLB_REG */
> #define DMA_TLB_FLUSH_GRANU_OFFSET 60
> #define DMA_TLB_GLOBAL_FLUSH (((u64)1) << 60)
> @@ -520,6 +523,7 @@ 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