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authorRadim Krčmář <rkrcmar@redhat.com>2014-12-04 18:30:41 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2014-12-05 13:57:49 +0100
commite08e833616f7eefebdacfd1d743d80ff3c3b2585 (patch)
treee49a16589b7c919f33a120a1dfe69046d9f0ff1f /arch
parent81dc01f7491b4bc68fbefe7ffe7ed88416ec9005 (diff)
downloadop-kernel-dev-e08e833616f7eefebdacfd1d743d80ff3c3b2585.zip
op-kernel-dev-e08e833616f7eefebdacfd1d743d80ff3c3b2585.tar.gz
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')
-rw-r--r--arch/x86/kvm/cpuid.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 644bfe8..8a80737 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)
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