From: Andrew Cooper Subject: x86/msr: Definitions for MSR_INTEL_CORE_THREAD_COUNT This is a model specific register which details the current configuration cores and threads in the package. Because of how Hyperthread and Core configuration works works in firmware, the MSR it is de-facto constant and will remain unchanged until the next system reset. It is a read only MSR (so unilaterally reject writes), but for now retain its leaky-on-read properties. Further CPUID/MSR work is required before we can start virtualising a consistent topology to the guest, and retaining the old behaviour is the safest course of action. Signed-off-by: Andrew Cooper Acked-by: Jan Beulich diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c index 4df4a59..a7f67d9 100644 --- a/xen/arch/x86/msr.c +++ b/xen/arch/x86/msr.c @@ -200,6 +200,10 @@ int guest_rdmsr(const struct vcpu *v, uint32_t msr, uint64_t *val) ARRAY_SIZE(msrs->dr_mask))]; break; + /* + * TODO: Implement when we have better topology representation. + case MSR_INTEL_CORE_THREAD_COUNT: + */ default: return X86EMUL_UNHANDLEABLE; } @@ -229,6 +233,7 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val) { uint64_t rsvd; + case MSR_INTEL_CORE_THREAD_COUNT: case MSR_INTEL_PLATFORM_INFO: case MSR_ARCH_CAPABILITIES: /* Read-only */ diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h index 11512d4..389f95f 100644 --- a/xen/include/asm-x86/msr-index.h +++ b/xen/include/asm-x86/msr-index.h @@ -32,6 +32,10 @@ #define EFER_KNOWN_MASK (EFER_SCE | EFER_LME | EFER_LMA | EFER_NX | \ EFER_SVME | EFER_FFXSE) +#define MSR_INTEL_CORE_THREAD_COUNT 0x00000035 +#define MSR_CTC_THREAD_MASK 0x0000ffff +#define MSR_CTC_CORE_MASK 0xffff0000 + /* Speculation Controls. */ #define MSR_SPEC_CTRL 0x00000048 #define SPEC_CTRL_IBRS (_AC(1, ULL) << 0)