Merge tag 'iommu-fixes-v4.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

Pull IOMMU fixes from Joerg Roedel:
 "Three fixes queued up:

   - fix an issue with command buffer overflow handling in the AMD IOMMU
     driver

   - add an additional context entry flush to the Intel VT-d driver to
     make sure any old context entry from kdump copying is flushed out
     of the cache

   - correct the encoding of the PASID table size in the Intel VT-d
     driver"

* tag 'iommu-fixes-v4.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Fix the left value check of cmd buffer
  iommu/vt-d: Fix pasid table size encoding
  iommu/vt-d: Flush old iommu caches for kdump when the device gets context mapped

2 files changed, 42 insertions, 2 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 019e02707cd5..3ef0f42984f2 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1023,7 +1023,7 @@ again:
         next_tail = (tail + sizeof(*cmd)) % CMD_BUFFER_SIZE;
         left      = (head - next_tail) % CMD_BUFFER_SIZE;
 
-        if (left <= 2) {
+        if (left <= 0x20) {
                 struct iommu_cmd sync_cmd;
                 int ret;
 
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c66c273dfd8a..8a185250ae5a 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2037,6 +2037,25 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
         if (context_present(context))
                 goto out_unlock;
 
+        /*
+         * For kdump cases, old valid entries may be cached due to the
+         * in-flight DMA and copied pgtable, but there is no unmapping
+         * behaviour for them, thus we need an explicit cache flush for
+         * the newly-mapped device. For kdump, at this point, the device
+         * is supposed to finish reset at its driver probe stage, so no
+         * in-flight DMA will exist, and we don't need to worry anymore
+         * hereafter.
+         */
+        if (context_copied(context)) {
+                u16 did_old = context_domain_id(context);
+
+                if (did_old >= 0 && did_old < cap_ndoms(iommu->cap))
+                        iommu->flush.flush_context(iommu, did_old,
+                                                   (((u16)bus) << 8) | devfn,
+                                                   DMA_CCMD_MASK_NOBIT,
+                                                   DMA_CCMD_DEVICE_INVL);
+        }
+
         pgd = domain->pgd;
 
         context_clear_entry(context);
@@ -5185,6 +5204,25 @@ static void intel_iommu_remove_device(struct device *dev)
 }
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
+#define MAX_NR_PASID_BITS (20)
+static inline unsigned long intel_iommu_get_pts(struct intel_iommu *iommu)
+{
+        /*
+         * Convert ecap_pss to extend context entry pts encoding, also
+         * respect the soft pasid_max value set by the iommu.
+         * - number of PASID bits = ecap_pss + 1
+         * - number of PASID table entries = 2^(pts + 5)
+         * Therefore, pts = ecap_pss - 4
+         * e.g. KBL ecap_pss = 0x13, PASID has 20 bits, pts = 15
+         */
+        if (ecap_pss(iommu->ecap) < 5)
+                return 0;
+
+        /* pasid_max is encoded as actual number of entries not the bits */
+        return find_first_bit((unsigned long *)&iommu->pasid_max,
+                        MAX_NR_PASID_BITS) - 5;
+}
+
 int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev *sdev)
 {
         struct device_domain_info *info;
@@ -5217,7 +5255,9 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev *sd
 
         if (!(ctx_lo & CONTEXT_PASIDE)) {
                 context[1].hi = (u64)virt_to_phys(iommu->pasid_state_table);
-                context[1].lo = (u64)virt_to_phys(iommu->pasid_table) | ecap_pss(iommu->ecap);
+                context[1].lo = (u64)virt_to_phys(iommu->pasid_table) |
+                        intel_iommu_get_pts(iommu);
+
                 wmb();
                 /* CONTEXT_TT_MULTI_LEVEL and CONTEXT_TT_DEV_IOTLB are both
                  * extended to permit requests-with-PASID if the PASIDE bit