| From: Sean Christopherson <sean.j.christopherson@intel.com> |
| Date: Tue, 7 Jan 2020 16:12:10 -0800 |
| Subject: KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM |
| |
| commit e30a7d623dccdb3f880fbcad980b0cb589a1da45 upstream. |
| |
| 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") |
| Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| [bwh: Backported to 3.16: adjust filename, context] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/x86/kvm/x86.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/arch/x86/kvm/x86.c |
| +++ b/arch/x86/kvm/x86.c |
| @@ -5734,7 +5734,7 @@ 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); |
