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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-09-12 15:16:00 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2014-09-14 16:26:05 +0200
commit85c8555ff07ef09261bd50d603cd4290cff5a8cc (patch)
tree34a42659b3e0cbb905c3083b37a62d4e9594d206 /virt
parent0b70068e47e8f0c813a902dc3d6def601fd15acb (diff)
KVM: check for !is_zero_pfn() in kvm_is_mmio_pfn()
Read-only memory ranges may be backed by the zero page, so avoid misidentifying it a a MMIO pfn. This fixes another issue I identified when testing QEMU+KVM_UEFI, where a read to an uninitialized emulated NOR flash brought in the zero page, but mapped as a read-write device region, because kvm_is_mmio_pfn() misidentifies it as a MMIO pfn due to its PG_reserved bit being set. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Fixes: b88657674d39 ("ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 33712fb26eb1..96ec6226e4ab 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -110,7 +110,7 @@ static bool largepages_enabled = true;
bool kvm_is_mmio_pfn(pfn_t pfn)
{
if (pfn_valid(pfn))
- return PageReserved(pfn_to_page(pfn));
+ return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn));
return true;
}

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