Commit 334df50a authored Jan 21, 2008 by Joerg Roedel Committed by Avi Kivity Mar 03, 2008

KVM: SVM: Fix lazy FPU switching



If the guest writes to cr0 and leaves the TS flag at 0 while vcpu->fpu_active
is also 0, the TS flag in the guest's cr0 gets lost. This leads to corrupt FPU
state an causes Windows Vista 64bit to crash very soon after boot.  This patch
fixes this bug.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Markus Rechberger <markus.rechberger@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

parent 038f2f72

arch/x86/kvm/svm.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -792,6 +792,8 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
		vcpu->arch.cr0 = cr0;
		cr0 \|= X86_CR0_PG \| X86_CR0_WP;
		cr0 &= ~(X86_CR0_CD \| X86_CR0_NW);
		if (!vcpu->fpu_active)
		cr0 \|= X86_CR0_TS;
		svm->vmcb->save.cr0 = cr0;
		}

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