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KVM: VMX: Pass cr0.mp through to the guest when the fpu is active

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When cr0.mp is clear, the guest doesn't expect a #NM in response to
a WAIT instruction.  Because we always keep cr0.mp set, it will get
a #NM, and potentially be confused.

Fix by keeping cr0.mp set only when the fpu is inactive, and passing
it through when inactive.

Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Analyzed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Avi Kivity 2010-01-24 16:26:40 +02:00 committed by Marcelo Tosatti
parent da15bf436b
commit 81231c698a
1 changed files with 9 additions and 6 deletions
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15
arch/x86/kvm/vmx.c
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@ -66,7 +66,7 @@ module_param(emulate_invalid_guest_state, bool, S_IRUGO);
#define KVM_GUEST_CR0_MASK \
(KVM_GUEST_CR0_MASK_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE)
#define KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST \
(X86_CR0_WP | X86_CR0_NE | X86_CR0_MP)
(X86_CR0_WP | X86_CR0_NE)
#define KVM_VM_CR0_ALWAYS_ON \
(KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE)
#define KVM_CR4_GUEST_OWNED_BITS \
@ -791,12 +791,15 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
static void vmx_fpu_activate(struct kvm_vcpu *vcpu)
{
ulong cr0;
if (vcpu->fpu_active)
return;
vcpu->fpu_active = 1;
vmcs_clear_bits(GUEST_CR0, X86_CR0_TS);
if (kvm_read_cr0_bits(vcpu, X86_CR0_TS))
vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
cr0 = vmcs_readl(GUEST_CR0);
cr0 &= ~(X86_CR0_TS | X86_CR0_MP);
cr0 |= kvm_read_cr0_bits(vcpu, X86_CR0_TS | X86_CR0_MP);
vmcs_writel(GUEST_CR0, cr0);
update_exception_bitmap(vcpu);
vcpu->arch.cr0_guest_owned_bits = X86_CR0_TS;
vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
@ -807,7 +810,7 @@ static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu);
static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
{
vmx_decache_cr0_guest_bits(vcpu);
vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
vmcs_set_bits(GUEST_CR0, X86_CR0_TS | X86_CR0_MP);
update_exception_bitmap(vcpu);
vcpu->arch.cr0_guest_owned_bits = 0;
vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
@ -1757,7 +1760,7 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
ept_update_paging_mode_cr0(&hw_cr0, cr0, vcpu);
if (!vcpu->fpu_active)
hw_cr0 |= X86_CR0_TS;
hw_cr0 |= X86_CR0_TS | X86_CR0_MP;
vmcs_writel(CR0_READ_SHADOW, cr0);
vmcs_writel(GUEST_CR0, hw_cr0);