The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From e30a7d623dccdb3f880fbcad980b0cb589a1da45 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Date: Tue, 7 Jan 2020 16:12:10 -0800
Subject: [PATCH] KVM: x86/mmu: Apply max PA check for MMIO sptes to 32-bit KVM
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@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 2992ff7b42a7..57e4dbddba72 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6193,7 +6193,7 @@ 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) && shadow_phys_bits == 52)
+ if (shadow_phys_bits == 52)
mask &= ~1ull;
kvm_mmu_set_mmio_spte_mask(mask, mask, ACC_WRITE_MASK | ACC_USER_MASK);
