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KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM

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[ Upstream commit e30a7d623dccdb3f880fbcad980b0cb589a1da45 ]

Remove the bogus 64-bit only condition from the check that disables MMIO
spte optimization when the system supports the max PA, i.e. doesn't have
any reserved PA bits.  32-bit KVM always uses PAE paging for the shadow
MMU, and per Intel's SDM:

  PAE paging translates 32-bit linear addresses to 52-bit physical
  addresses.

The kernel's restrictions on max physical addresses are limits on how
much memory the kernel can reasonably use, not what physical addresses
are supported by hardware.

Fixes: ce88decffd17 ("KVM: MMU: mmio page fault support")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sean Christopherson 2020-01-07 16:12:10 -08:00 committed by Greg Kroah-Hartman
parent 0eed3d7100
commit 6b26d90d12
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kvm/x86.c
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@ -6314,7 +6314,7 @@ static void kvm_set_mmio_spte_mask(void)
* If reserved bit is not supported, clear the present bit to disable
* mmio page fault.
*/
if (IS_ENABLED(CONFIG_X86_64) && maxphyaddr == 52)
if (maxphyaddr == 52)
mask &= ~1ull;
kvm_mmu_set_mmio_spte_mask(mask, mask);