iommu/vt-d: Add __iommu_flush_iotlb_psi()

Add __iommu_flush_iotlb_psi() to do the psi iotlb flush with a DID input
rather than calculating it within the helper.

This is useful when flushing cache for parent domain which reuses DIDs of
its nested domains.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240208082307.15759-3-yi.l.liu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel/iommu.c

@@ -1368,6 +1368,46 @@ static void domain_flush_pasid_iotlb(struct intel_iommu *iommu,
 	spin_unlock_irqrestore(&domain->lock, flags);
 }
 
+static void __iommu_flush_iotlb_psi(struct intel_iommu *iommu, u16 did,
+				    unsigned long pfn, unsigned int pages,
+				    int ih)
+{
+	unsigned int aligned_pages = __roundup_pow_of_two(pages);
+	unsigned long bitmask = aligned_pages - 1;
+	unsigned int mask = ilog2(aligned_pages);
+	u64 addr = (u64)pfn << VTD_PAGE_SHIFT;
+
+	/*
+	 * PSI masks the low order bits of the base address. If the
+	 * address isn't aligned to the mask, then compute a mask value
+	 * needed to ensure the target range is flushed.
+	 */
+	if (unlikely(bitmask & pfn)) {
+		unsigned long end_pfn = pfn + pages - 1, shared_bits;
+
+		/*
+		 * Since end_pfn <= pfn + bitmask, the only way bits
+		 * higher than bitmask can differ in pfn and end_pfn is
+		 * by carrying. This means after masking out bitmask,
+		 * high bits starting with the first set bit in
+		 * shared_bits are all equal in both pfn and end_pfn.
+		 */
+		shared_bits = ~(pfn ^ end_pfn) & ~bitmask;
+		mask = shared_bits ? __ffs(shared_bits) : BITS_PER_LONG;
+	}
+
+	/*
+	 * Fallback to domain selective flush if no PSI support or
+	 * the size is too big.
+	 */
+	if (!cap_pgsel_inv(iommu->cap) || mask > cap_max_amask_val(iommu->cap))
+		iommu->flush.flush_iotlb(iommu, did, 0, 0,
+					 DMA_TLB_DSI_FLUSH);
+	else
+		iommu->flush.flush_iotlb(iommu, did, addr | ih, mask,
+					 DMA_TLB_PSI_FLUSH);
+}
+
 static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
 				  struct dmar_domain *domain,
 				  unsigned long pfn, unsigned int pages,
@@ -1384,42 +1424,10 @@ static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
 	if (ih)
 		ih = 1 << 6;
 
-	if (domain->use_first_level) {
+	if (domain->use_first_level)
 		domain_flush_pasid_iotlb(iommu, domain, addr, pages, ih);
-	} else {
-		unsigned long bitmask = aligned_pages - 1;
-
-		/*
-		 * PSI masks the low order bits of the base address. If the
-		 * address isn't aligned to the mask, then compute a mask value
-		 * needed to ensure the target range is flushed.
-		 */
-		if (unlikely(bitmask & pfn)) {
-			unsigned long end_pfn = pfn + pages - 1, shared_bits;
-
-			/*
-			 * Since end_pfn <= pfn + bitmask, the only way bits
-			 * higher than bitmask can differ in pfn and end_pfn is
-			 * by carrying. This means after masking out bitmask,
-			 * high bits starting with the first set bit in
-			 * shared_bits are all equal in both pfn and end_pfn.
-			 */
-			shared_bits = ~(pfn ^ end_pfn) & ~bitmask;
-			mask = shared_bits ? __ffs(shared_bits) : BITS_PER_LONG;
-		}
-
-		/*
-		 * Fallback to domain selective flush if no PSI support or
-		 * the size is too big.
-		 */
-		if (!cap_pgsel_inv(iommu->cap) ||
-		    mask > cap_max_amask_val(iommu->cap))
-			iommu->flush.flush_iotlb(iommu, did, 0, 0,
-							DMA_TLB_DSI_FLUSH);
-		else
-			iommu->flush.flush_iotlb(iommu, did, addr | ih, mask,
-							DMA_TLB_PSI_FLUSH);
-	}
+	else
+		__iommu_flush_iotlb_psi(iommu, did, pfn, pages, ih);
 
 	/*
 	 * In caching mode, changes of pages from non-present to present require