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Subject[PATCH] KVM: x86: reintroduce kvm_is_mmio_pfn
Date
The call to get_mt_mask was really using kvm_is_reserved_pfn to
detect an MMIO-backed page. In this case, we want "false" to be
returned for the zero page.

Reintroduce a separate kvm_is_mmio_pfn predicate for this use
only.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/mmu.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f807496b62c2..44171462bd2a 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2479,6 +2479,14 @@ static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
return 0;
}

+static bool kvm_is_mmio_pfn(pfn_t pfn)
+{
+ if (pfn_valid(pfn))
+ return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn));
+
+ return true;
+}
+
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned pte_access, int level,
gfn_t gfn, pfn_t pfn, bool speculative,
@@ -2506,7 +2514,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
spte |= PT_PAGE_SIZE_MASK;
if (tdp_enabled)
spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
- kvm_is_reserved_pfn(pfn));
+ kvm_is_mmio_pfn(pfn));

if (host_writable)
spte |= SPTE_HOST_WRITEABLE;
--
1.8.3.1


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