KVM: MTRR: treat memory as writeback if MTRR is disabled in guest CPUID (e24dea2a) · Commits · 戴 / test

arch/x86/kvm/cpuid.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,14 @@ static inline bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu)
		return best && (best->ecx & bit(X86_FEATURE_XSAVE));
		}

		static inline bool guest_cpuid_has_mtrr(struct kvm_vcpu *vcpu)
		{
		struct kvm_cpuid_entry2 *best;

		best = kvm_find_cpuid_entry(vcpu, 1, 0);
		return best && (best->edx & bit(X86_FEATURE_MTRR));
		}

		static inline bool guest_cpuid_has_tsc_adjust(struct kvm_vcpu *vcpu)
		{
		struct kvm_cpuid_entry2 *best;

+11 −3

Original line number	Diff line number	Diff line
		@@ -120,14 +120,22 @@ static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state)
		return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;
		}

		static u8 mtrr_disabled_type(void)
		static u8 mtrr_disabled_type(struct kvm_vcpu *vcpu)
		{
		/*
		* Intel SDM 11.11.2.2: all MTRRs are disabled when
		* IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC
		* memory type is applied to all of physical memory.
		*
		* However, virtual machines can be run with CPUID such that
		* there are no MTRRs. In that case, the firmware will never
		* enable MTRRs and it is obviously undesirable to run the
		* guest entirely with UC memory and we use WB.
		*/
		if (guest_cpuid_has_mtrr(vcpu))
		return MTRR_TYPE_UNCACHABLE;
		else
		return MTRR_TYPE_WRBACK;
		}

		/*
		@@ -675,7 +683,7 @@ u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
		}

		if (iter.mtrr_disabled)
		return mtrr_disabled_type();
		return mtrr_disabled_type(vcpu);

		/* not contained in any MTRRs. */
		if (type == -1)