[libvirt] [PATCH v2 4/7] cpu_x86: Read CPU features from IA32_ARCH_CAPABILITIES MSR

This is used by the host capabilities code to construct host CPU definition. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; Reviewed-by: Ján Tomko <jtomko(a)redhat.com&gt; --- src/cpu/cpu_x86.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c index a7ec0f7095..5f051950de 100644 --- a/src/cpu/cpu_x86.c +++ b/src/cpu/cpu_x86.c @@ -2773,6 +2773,28 @@ virCPUx86GetHost(virCPUDefPtr cpu, cpuidSet(CPUX86_EXTENDED, cpuData) < 0) goto cleanup; + /* Read the IA32_ARCH_CAPABILITIES MSR (0x10a) if supported. + * This is best effort since there might be no way to read the MSR + * when we are not running as root. */ + if (virCPUx86DataCheckFeature(cpuData, "arch-capabilities") == 1) { + uint64_t msr; + unsigned long index = 0x10a; + + if (virHostCPUGetMSR(index, &msr) == 0) { + virCPUx86DataItem item = { + .type = VIR_CPU_X86_DATA_MSR, + .data.msr = { + .index = index, + .eax = msr & 0xffffffff, + .edx = msr >> 32, + }, + }; + + if (virCPUx86DataAdd(cpuData, &item) < 0) + return -1; + } + } + ret = x86DecodeCPUData(cpu, cpuData, models); cpu->microcodeVersion = virHostCPUGetMicrocodeVersion(); -- 2.22.0