On 09/23/2016 12:45 PM, Eduardo Habkost wrote:
The code that calculates the set of supported XSAVE components on
CPUID looks at ext_save_areas to find out which components should
be enabled. However, if there are zeroed entries in the
ext_save_areas array, the
((env->features[esa->feature] & esa->bits) == esa->bits)
check will always succeed and QEMU will unconditionally try to
enable the component.
Luckily this never caused any problems because the only missing
entry in ext_save_areas is the PT State component (bit 8), and
KVM currently doesn't support it (so it was cleared on ena_mask).
But the code was still incorrect and would break if KVM starts
returning CPUID[EAX=0xD,ECX=0].EAX[bit 8] as supported on
GET_SUPPORTED_CPUID.
Fix the problem by changing the code to not enable a XSAVE
component if ExtSaveArea::bits is zero.
Signed-off-by: Eduardo Habkost <ehabk...@redhat.com>
---
target-i386/cpu.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Reviewed-by: Richard Henderson <r...@twiddle.net>
r~
