[PATCH v8 06/10] iommu/vt-d: Cache virtual command capability register

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

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 f2f5d75da94a..3f98dd9ad004 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -953,6 +953,7 @@ 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 ee26989df008..4d25141ec3df 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -189,6 +189,9 @@
 #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 */
+
 /* IOTLB_REG */
 #define DMA_TLB_FLUSH_GRANU_OFFSET  60
 #define DMA_TLB_GLOBAL_FLUSH (((u64)1) << 60)
@@ -531,6 +534,7 @@ 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