amd_iommu: HATDis/HATS=11 support

Add a way to disable DMA translation support in AMD IOMMU by
allowing to set IVHD HATDis to 1, and exposing HATS (Host Address
Translation Size) as Reserved value.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20250919213515.917111-23-alejandro.j.jimenez@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index b6851784fb..378e0cb55e 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -107,6 +107,9 @@ uint64_t amdvi_extended_feature_register(AMDVIState *s)
     if (s->xtsup) {
         feature |= AMDVI_FEATURE_XT;
     }
+    if (!s->iommu.dma_translation) {
+        feature |= AMDVI_HATS_MODE_RESERVED;
+    }
 
     return feature;
 }
@@ -472,6 +475,9 @@ static inline uint64_t amdvi_get_perms(uint64_t entry)
 static bool amdvi_validate_dte(AMDVIState *s, uint16_t devid,
                                uint64_t *dte)
 {
+
+    uint64_t root;
+
     if ((dte[0] & AMDVI_DTE_QUAD0_RESERVED) ||
         (dte[1] & AMDVI_DTE_QUAD1_RESERVED) ||
         (dte[2] & AMDVI_DTE_QUAD2_RESERVED) ||
@@ -482,6 +488,19 @@ static bool amdvi_validate_dte(AMDVIState *s, uint16_t devid,
         return false;
     }
 
+    /*
+     * 1 = Host Address Translation is not supported. Value in MMIO Offset
+     * 0030h[HATS] is not meaningful. A non-zero host page table root pointer
+     * in the DTE would result in an ILLEGAL_DEV_TABLE_ENTRY event.
+     */
+    root = (dte[0] & AMDVI_DEV_PT_ROOT_MASK) >> 12;
+    if (root && !s->iommu.dma_translation) {
+        amdvi_log_illegaldevtab_error(s, devid,
+                                      s->devtab +
+                                      devid * AMDVI_DEVTAB_ENTRY_SIZE, 0);
+        return false;
+    }
+
     return true;
 }