[v1] intel_iommu: Enable stage-1 translation for passthrough device

[PATCH rfcv3 20/21] intel_iommu: Bypass replay in stage-1 page table mode

Zhenzhong Duan posted 21 patches 5 months, 4 weeks ago

Diff against v1 v2 v3 v4 v5
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Maintainers: Yi Liu <yi.l.liu@intel.com>, Eric Auger <eric.auger@redhat.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>, "Clément Mathieu--Drif" <clement.mathieu--drif@eviden.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Alex Williamson <alex.williamson@redhat.com>, "Cédric Le Goater" <clg@redhat.com>

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[PATCH rfcv3 20/21] intel_iommu: Bypass replay in stage-1 page table mode

Posted by Zhenzhong Duan 5 months, 4 weeks ago

VFIO utilizes replay to setup initial shadow iommu mappings.
But when stage-1 page table is configured, it is passed to
host to construct nested page table, there is no replay needed.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 hw/i386/intel_iommu.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index b8f3b8effa..e7c662f609 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -5768,6 +5768,14 @@ static void vtd_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n)
     VTDContextEntry ce;
     DMAMap map = { .iova = 0, .size = HWADDR_MAX };
 
+    /*
+     * Replay on stage-1 page table is meaningless as stage-1 page table
+     * is passthroughed to host to construct nested page table
+     */
+    if (s->flts && s->root_scalable) {
+        return;
+    }
+
     /* replay is protected by BQL, page walk will re-setup it safely */
     iova_tree_remove(vtd_as->iova_tree, map);
 
-- 
2.34.1