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Commit 9c1c3fac authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
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x86, kvm: use kernel_fpu_begin/end() in kvm_load/put_guest_fpu() 



kvm's guest fpu save/restore should be wrapped around
kernel_fpu_begin/end(). This will avoid for example taking a DNA
in kvm_load_guest_fpu() when it tries to load the fpu immediately
after doing unlazy_fpu() on the host side.

More importantly this will prevent the host process fpu from being
corrupted.

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-4-git-send-email-suresh.b.siddha@intel.com


Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 377ffbcc

arch/x86/kvm/x86.c

+2 −1
Original line number Diff line number Diff line
@@ -5972,7 +5972,7 @@ void kvm_load_guest_fpu(struct kvm_vcpu *vcpu) 
	 */

	kvm_put_guest_xcr0(vcpu);

	vcpu->guest_fpu_loaded = 1;

	unlazy_fpu(current);

	kernel_fpu_begin();

	fpu_restore_checking(&vcpu->arch.guest_fpu);

	trace_kvm_fpu(1);

}
@@ -5986,6 +5986,7 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) 


	vcpu->guest_fpu_loaded = 0;

	fpu_save_init(&vcpu->arch.guest_fpu);

	kernel_fpu_end();

	++vcpu->stat.fpu_reload;

	kvm_make_request(KVM_REQ_DEACTIVATE_FPU, vcpu);

	trace_kvm_fpu(0);