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x86, kvm: use kernel_fpu_begin/end() in kvm_load/put_guest_fpu()

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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: Suresh 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: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Suresh Siddha 2012-08-24 14:12:59 -07:00 committed by H. Peter Anvin
parent 377ffbcc53
commit 9c1c3fac53
1 changed files with 2 additions and 1 deletions
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3
arch/x86/kvm/x86.c
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@ -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);