From f7e1caa3302f705abe196b8a021cfa52750749ff Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Thu, 8 Nov 2018 06:29:38 +0000
Subject: [PATCH 10/35] intel_iommu: handle invalid ce for shadow sync
RH-Author: Peter Xu <peterx@redhat.com>
Message-id: <20181108062938.21143-8-peterx@redhat.com>
Patchwork-id: 82966
O-Subject: [RHEL-8 qemu-kvm PATCH 7/7] intel_iommu: handle invalid ce for shadow sync
Bugzilla: 1625173
RH-Acked-by: Auger Eric <eric.auger@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
Bugzilla: 1629616
We should handle VTD_FR_CONTEXT_ENTRY_P properly when synchronizing
shadow page tables. Having invalid context entry there is perfectly
valid when we move a device out of an existing domain. When that
happens, instead of posting an error we invalidate the whole region.
Without this patch, QEMU will crash if we do these steps:
(1) start QEMU with VT-d IOMMU and two 10G NICs (ixgbe)
(2) bind the NICs with vfio-pci in the guest
(3) start testpmd with the NICs applied
(4) stop testpmd
(5) rebind the NIC back to ixgbe kernel driver
The patch should fix it.
Reported-by: Pei Zhang <pezhang@redhat.com>
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1627272
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit c28b535d083d0a263d38d9ceeada83cdae8c64f0)
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
hw/i386/intel_iommu.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index c95128d..12af410 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -38,6 +38,7 @@
#include "trace.h"
static void vtd_address_space_refresh_all(IntelIOMMUState *s);
+static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n);
static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val,
uint64_t wmask, uint64_t w1cmask)
@@ -1066,11 +1067,27 @@ static int vtd_sync_shadow_page_table(VTDAddressSpace *vtd_as)
{
int ret;
VTDContextEntry ce;
+ IOMMUNotifier *n;
ret = vtd_dev_to_context_entry(vtd_as->iommu_state,
pci_bus_num(vtd_as->bus),
vtd_as->devfn, &ce);
if (ret) {
+ if (ret == -VTD_FR_CONTEXT_ENTRY_P) {
+ /*
+ * It's a valid scenario to have a context entry that is
+ * not present. For example, when a device is removed
+ * from an existing domain then the context entry will be
+ * zeroed by the guest before it was put into another
+ * domain. When this happens, instead of synchronizing
+ * the shadow pages we should invalidate all existing
+ * mappings and notify the backends.
+ */
+ IOMMU_NOTIFIER_FOREACH(n, &vtd_as->iommu) {
+ vtd_address_space_unmap(vtd_as, n);
+ }
+ ret = 0;
+ }
return ret;
}
--
1.8.3.1