KVM: fx_init() needs preemption disabled while it plays with the FPU state
Now that kvm generally runs with preemption enabled, we need to protect
the fpu intialization sequence.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 7aeaaba..5b42731 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -693,10 +693,13 @@
} *fx_image;
+ /* Initialize guest FPU by resetting ours and saving into guest's */
+ preempt_disable();
fx_save(vcpu->host_fx_image);
fpu_init();
fx_save(vcpu->guest_fx_image);
fx_restore(vcpu->host_fx_image);
+ preempt_enable();
fx_image = (struct fx_image_s *)vcpu->guest_fx_image;
fx_image->mxcsr = 0x1f80;