commit d9d32478ed4543539322761c19a73edf5d0be059
author Zhenzhong Duan <zhenzhong.duan@intel.com> Thu Dec 12 16:37:56 2024 +0800
committer Michael S. Tsirkin <mst@redhat.com> Wed Jan 15 13:06:36 2025 -0500
tree f0fa29919e8d409f8d1bc92efad23181598b66dd
parent aa68a9fbdb81c47c2a48a3199559df470c3d9eba

intel_iommu: Introduce a property to control FS1GP cap bit setting

This gives user flexibility to turn off FS1GP for debug purpose.

It is also useful for future nesting feature. When host IOMMU doesn't
support FS1GP but vIOMMU does, nested page table on host side works
after turning FS1GP off in vIOMMU.

This property has no effect when vIOMMU is in legacy mode or x-flts=off
in scalable modme.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Clément Mathieu--Drif<clement.mathieu--drif@eviden.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20241212083757.605022-20-zhenzhong.duan@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/intel_iommu.c

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 0111186..f366c22 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -3834,6 +3834,7 @@
     DEFINE_PROP_BOOL("dma-drain", IntelIOMMUState, dma_drain, true),
     DEFINE_PROP_BOOL("dma-translation", IntelIOMMUState, dma_translation, true),
     DEFINE_PROP_BOOL("stale-tm", IntelIOMMUState, stale_tm, false),
+    DEFINE_PROP_BOOL("fs1gp", IntelIOMMUState, fs1gp, true),
 };
 
 /* Read IRTE entry with specific index */
@@ -4561,7 +4562,9 @@
     /* TODO: read cap/ecap from host to decide which cap to be exposed. */
     if (s->flts) {
         s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_FLTS;
-        s->cap |= VTD_CAP_FS1GP;
+        if (s->fs1gp) {
+            s->cap |= VTD_CAP_FS1GP;
+        }
     } else if (s->scalable_mode) {
         s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS;
     }

include/hw/i386/intel_iommu.h

diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 72428fe..9e92bff 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -307,6 +307,7 @@
     bool dma_drain;                 /* Whether DMA r/w draining enabled */
     bool dma_translation;           /* Whether DMA translation supported */
     bool pasid;                     /* Whether to support PASID */
+    bool fs1gp;                     /* First Stage 1-GByte Page Support */
 
     /* Transient Mapping, Reserved(0) since VTD spec revision 3.2 */
     bool stale_tm;