KVM: vmx: update sec exec controls for UMIP iff emulating UMIP (64f7a115) · Commits · 戴 / test

Update SECONDARY_EXEC_DESC for UMIP emulation if and only UMIP is actually being emulated. Skipping the VMCS update eliminates unnecessary VMREAD/VMWRITE when UMIP is supported in hardware, and on platforms that don't have SECONDARY_VM_EXEC_CONTROL. The latter case resolves a bug where KVM would fill the kernel log with warnings due to failed VMWRITEs on older platforms. Fixes: ("KVM: vmx: add support for emulating UMIP") Cc: stable@vger.kernel.org #4.16 Reported-by:

Paolo Zeppegno <pzeppegno@gmail.com> Suggested-by:

Paolo Bonzini <pbonzini@redhat.com> Suggested-by:

Radim KrÄmÃ¡Å™ <rkrcmar@redhat.com> Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

+15 −13

Original line number	Diff line number	Diff line
		@@ -1494,6 +1494,12 @@ static inline bool cpu_has_vmx_vmfunc(void)
		SECONDARY_EXEC_ENABLE_VMFUNC;
		}

		static bool vmx_umip_emulated(void)
		{
		return vmcs_config.cpu_based_2nd_exec_ctrl &
		SECONDARY_EXEC_DESC;
		}

		static inline bool report_flexpriority(void)
		{
		return flexpriority_enabled;
		@@ -4761,7 +4767,8 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
		else
		hw_cr4 \|= KVM_PMODE_VM_CR4_ALWAYS_ON;

		if ((cr4 & X86_CR4_UMIP) && !boot_cpu_has(X86_FEATURE_UMIP)) {
		if (!boot_cpu_has(X86_FEATURE_UMIP) && vmx_umip_emulated()) {
		if (cr4 & X86_CR4_UMIP) {
		vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL,
		SECONDARY_EXEC_DESC);
		hw_cr4 &= ~X86_CR4_UMIP;
		@@ -4769,6 +4776,7 @@ static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
		!nested_cpu_has2(get_vmcs12(vcpu), SECONDARY_EXEC_DESC))
		vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL,
		SECONDARY_EXEC_DESC);
		}

		if (cr4 & X86_CR4_VMXE) {
		/*
		@@ -9497,12 +9505,6 @@ static bool vmx_xsaves_supported(void)
		SECONDARY_EXEC_XSAVES;
		}

		static bool vmx_umip_emulated(void)
		{
		return vmcs_config.cpu_based_2nd_exec_ctrl &
		SECONDARY_EXEC_DESC;
		}

		static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
		{
		u32 exit_intr_info;

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