3.16.84-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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);
