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| author | Radim Krčmář <rkrcmar@redhat.com> | 2014-12-04 18:30:41 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-12-05 13:57:49 +0100 |
| commit | e08e833616f7eefebdacfd1d743d80ff3c3b2585 (patch) | |
| tree | e49a16589b7c919f33a120a1dfe69046d9f0ff1f /arch/x86/kvm/cpuid.c | |
| parent | 81dc01f7491b4bc68fbefe7ffe7ed88416ec9005 (diff) | |
| download | lwn-e08e833616f7eefebdacfd1d743d80ff3c3b2585.tar.gz lwn-e08e833616f7eefebdacfd1d743d80ff3c3b2585.zip | |
KVM: cpuid: recompute CPUID 0xD.0:EBX,ECX
We reused host EBX and ECX, but KVM might not support all features;
emulated XSAVE size should be smaller.
EBX depends on unknown XCR0, so we default to ECX.
SDM CPUID (EAX = 0DH, ECX = 0):
EBX Bits 31-00: Maximum size (bytes, from the beginning of the
XSAVE/XRSTOR save area) required by enabled features in XCR0. May
be different than ECX if some features at the end of the XSAVE save
area are not enabled.
ECX Bit 31-00: Maximum size (bytes, from the beginning of the
XSAVE/XRSTOR save area) of the XSAVE/XRSTOR save area required by
all supported features in the processor, i.e all the valid bit
fields in XCR0.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Tested-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 644bfe828ce1..8a80737ee6e6 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -464,6 +464,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, u64 supported = kvm_supported_xcr0(); entry->eax &= supported; + entry->ebx = xstate_required_size(supported, false); + entry->ecx = entry->ebx; entry->edx &= supported >> 32; entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; if (!supported) |