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From 94edd1b203f3a88065ce05d9e027b24a3e8eed2f Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Tue, 2 Apr 2019 07:25:28 +0100
Subject: [PATCH 4/7] intel_iommu: fix operator in vtd_switch_address_space

RH-Author: Peter Xu <peterx@redhat.com>
Message-id: <20190402072531.23771-2-peterx@redhat.com>
Patchwork-id: 85298
O-Subject: [RHEL-8.1 qemu-kvm PATCH 1/4] intel_iommu: fix operator in vtd_switch_address_space
Bugzilla: 1662272
RH-Acked-by: Wei Huang <wei@redhat.com>
RH-Acked-by: Xiao Wang <jasowang@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>

When calculating use_iommu, we wanted to first detect whether DMAR is
enabled, then check whether PT is enabled if DMAR is enabled.  However
in the current code we used "&" rather than "&&" so the ordering
requirement is lost (instead it'll be an "AND" operation).  This could
introduce errors dumped in QEMU console when rebooting a guest with
both assigned device and vIOMMU, like:

  qemu-system-x86_64: vtd_dev_to_context_entry: invalid root entry:
  rsvd=0xf000ff53f000e2c3, val=0xf000ff53f000ff53 (reserved nonzero)

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 2a078b1080917dc6143783e1dd645e188d11dc8f)
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 hw/i386/intel_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 12af410..7170266 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1145,7 +1145,7 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
 
     assert(as);
 
-    use_iommu = as->iommu_state->dmar_enabled & !vtd_dev_pt_enabled(as);
+    use_iommu = as->iommu_state->dmar_enabled && !vtd_dev_pt_enabled(as);
 
     trace_vtd_switch_address_space(pci_bus_num(as->bus),
                                    VTD_PCI_SLOT(as->devfn),
-- 
1.8.3.1