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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2013-04-15 23:30:13 -0300 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-05-08 12:47:43 +0300 |
| commit | 42bdf991f4cad9678ee2b98c5c2e9299a3f986ef (patch) | |
| tree | b0b91769efbecf318e968477cb1b7cc68d0defbd /virt | |
| parent | 5af43c24ca59a448c9312dd4a4a51d27ec3b9a73 (diff) | |
| download | op-kernel-dev-42bdf991f4cad9678ee2b98c5c2e9299a3f986ef.zip op-kernel-dev-42bdf991f4cad9678ee2b98c5c2e9299a3f986ef.tar.gz | |
KVM: x86: fix maintenance of guest/host xcr0 state
Emulation of xcr0 writes zero guest_xcr0_loaded variable so that
subsequent VM-entry reloads CPU's xcr0 with guests xcr0 value.
However, this is incorrect because guest_xcr0_loaded variable is
read to decide whether to reload hosts xcr0.
In case the vcpu thread is scheduled out after the guest_xcr0_loaded = 0
assignment, and scheduler decides to preload FPU:
switch_to
{
__switch_to
__math_state_restore
restore_fpu_checking
fpu_restore_checking
if (use_xsave())
fpu_xrstor_checking
xrstor64 with CPU's xcr0 == guests xcr0
Fix by properly restoring hosts xcr0 during emulation of xcr0 writes.
Analyzed-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'virt')
0 files changed, 0 insertions, 0 deletions
