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/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 346f1cf..0164ae5 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -3647,6 +3647,7 @@ int hvm_msr_write_intercept(unsigned int msr, uint64_t msr_content, wrmsrl(MSR_FLUSH_CMD, msr_content); break; + case MSR_INTEL_CORE_THREAD_COUNT: case MSR_ARCH_CAPABILITIES: /* Read-only */ case MSR_TSX_FORCE_ABORT: diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c index 8635f70..f3c8705 100644 --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -2860,6 +2860,7 @@ static int priv_op_write_msr(unsigned int reg, uint64_t val, wrmsrl(reg, val); return X86EMUL_OKAY; + case MSR_INTEL_CORE_THREAD_COUNT: case MSR_INTEL_PLATFORM_INFO: case MSR_ARCH_CAPABILITIES: /* The MSR is read-only. */ diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h index 8dec40e..bc72476 100644 --- a/xen/include/asm-x86/msr-index.h +++ b/xen/include/asm-x86/msr-index.h @@ -34,6 +34,10 @@ #define EFER_KNOWN_MASK (EFER_SCE | EFER_LME | EFER_LMA | EFER_NX | \ EFER_SVME | EFER_LMSLE | 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)