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Commit 1b2fd70c authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
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KVM: Add FFXSR support 



AMD K10 CPUs implement the FFXSR feature that gets enabled using
EFER. Let's check if the virtual CPU description includes that
CPUID feature bit and allow enabling it then.

This is required for Windows Server 2008 in Hyper-V mode.

v2 adds CPUID capability exposure

Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent d2062693

arch/x86/kvm/svm.c

+3 −0
Original line number Diff line number Diff line
@@ -417,6 +417,9 @@ static __init int svm_hardware_setup(void) 
	if (boot_cpu_has(X86_FEATURE_NX))

		kvm_enable_efer_bits(EFER_NX);



	if (boot_cpu_has(X86_FEATURE_FXSR_OPT))

		kvm_enable_efer_bits(EFER_FFXSR);



	if (nested) {

		printk(KERN_INFO "kvm: Nested Virtualization enabled\n");

		kvm_enable_efer_bits(EFER_SVME);

arch/x86/kvm/x86.c

+12 −0
Original line number Diff line number Diff line
@@ -490,6 +490,17 @@ static void set_efer(struct kvm_vcpu *vcpu, u64 efer) 
		return;

	}



	if (efer & EFER_FFXSR) {

		struct kvm_cpuid_entry2 *feat;



		feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);

		if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT))) {

			printk(KERN_DEBUG "set_efer: #GP, enable FFXSR w/o CPUID capability\n");

			kvm_inject_gp(vcpu, 0);

			return;

		}

	}



	if (efer & EFER_SVME) {

		struct kvm_cpuid_entry2 *feat;
@@ -1240,6 +1251,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 
#ifdef CONFIG_X86_64

		bit(X86_FEATURE_LM) |

#endif

		bit(X86_FEATURE_FXSR_OPT) |

		bit(X86_FEATURE_MMXEXT) |

		bit(X86_FEATURE_3DNOWEXT) |

		bit(X86_FEATURE_3DNOW);