Merge tag 'kvm-x86-mmu-6.7' of https://github.com/kvm-x86/linux into HEAD

KVM x86 MMU changes for 6.7:

 - Clean up code that deals with honoring guest MTRRs when the VM has
   non-coherent DMA and host MTRRs are ignored, i.e. EPT is enabled.

 - Zap EPT entries when non-coherent DMA assignment stops/start to prevent
   using stale entries with the wrong memtype.

 - Don't ignore guest PAT for CR0.CD=1 && KVM_X86_QUIRK_CD_NW_CLEARED=y, as
   there's zero reason to ignore guest PAT if the effective MTRR memtype is WB.
   This will also allow for future optimizations of handling guest MTRR updates
   for VMs with non-coherent DMA and the quirk enabled.

 - Harden the fast page fault path to guard against encountering an invalid
   root when walking SPTEs.

1 files changed, 3 insertions, 6 deletions

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c721a6785909..610e37e215be 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7579,8 +7579,6 @@ static int vmx_vm_init(struct kvm *kvm)
 
 static u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
 {
-	u8 cache;
-
 	/* We wanted to honor guest CD/MTRR/PAT, but doing so could result in
 	 * memory aliases with conflicting memory types and sometimes MCEs.
 	 * We have to be careful as to what are honored and when.
@@ -7607,11 +7605,10 @@ static u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
 
 	if (kvm_read_cr0_bits(vcpu, X86_CR0_CD)) {
 		if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
-			cache = MTRR_TYPE_WRBACK;
+			return MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT;
 		else
-			cache = MTRR_TYPE_UNCACHABLE;
-
-		return (cache << VMX_EPT_MT_EPTE_SHIFT) | VMX_EPT_IPAT_BIT;
+			return (MTRR_TYPE_UNCACHABLE << VMX_EPT_MT_EPTE_SHIFT) |
+				VMX_EPT_IPAT_BIT;
 	}
 
 	return kvm_mtrr_get_guest_memory_type(vcpu, gfn) << VMX_EPT_MT_EPTE_SHIFT;