diff options
| author | Eduardo Habkost <ehabkost@redhat.com> | 2016-09-22 18:58:39 -0300 |
|---|---|---|
| committer | Eduardo Habkost <ehabkost@redhat.com> | 2016-09-27 16:17:17 -0300 |
| commit | 9646f4927faf68e8690588c2fd6dc9834c440b58 (patch) | |
| tree | 1be672905be21c3646e2f38ef7aaa3598a06c995 /target-i386 | |
| parent | 2d5312da566e4424a807d078da05f92ee7be3eec (diff) | |
| download | qemu-9646f4927faf68e8690588c2fd6dc9834c440b58.tar.gz | |
target-i386: Don't try to enable PT State xsave component
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.
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Diffstat (limited to 'target-i386')
| -rw-r--r-- | target-i386/cpu.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/target-i386/cpu.c b/target-i386/cpu.c index cc07fdbf8b..25ab4f8b41 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2514,7 +2514,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, *ecx = 0x240; for (i = 2; i < ARRAY_SIZE(x86_ext_save_areas); i++) { const ExtSaveArea *esa = &x86_ext_save_areas[i]; - if ((env->features[esa->feature] & esa->bits) == esa->bits + if ((env->features[esa->feature] & esa->bits) && ((ena_mask >> i) & 1) != 0) { if (i < 32) { *eax |= 1u << i; @@ -2530,7 +2530,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, *eax = env->features[FEAT_XSAVE]; } else if (count < ARRAY_SIZE(x86_ext_save_areas)) { const ExtSaveArea *esa = &x86_ext_save_areas[count]; - if ((env->features[esa->feature] & esa->bits) == esa->bits + if ((env->features[esa->feature] & esa->bits) && ((ena_mask >> count) & 1) != 0) { *eax = esa->size; *ebx = esa->offset; @@ -2766,7 +2766,7 @@ static void x86_cpu_reset(CPUState *s) } for (i = 2; i < ARRAY_SIZE(x86_ext_save_areas); i++) { const ExtSaveArea *esa = &x86_ext_save_areas[i]; - if ((env->features[esa->feature] & esa->bits) == esa->bits) { + if (env->features[esa->feature] & esa->bits) { xcr0 |= 1ull << i; } } |