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    Subject[PATCH] kvm: x86: emulate MSR_PLATFORM_INFO msr bits
    Date
    For intel platform, The BzyMhz field of Turbostat shows zero
    due to the missing of part msr bits of MSR_PLATFORM_INFO.

    Acquire necessary msr bits, and expose following msr info to guest,
    to make sure guest can get correct turbo frequency info.

    MSR_PLATFORM_INFO bits
    bit 15:8, Maximum Non-Turbo Ratio (MAX_NON_TURBO_LIM_RATIO)
    bit 47:40, Maximum Efficiency Ratio (MAX_EFFICIENCY_RATIO)

    Signed-off-by: Hao Xiang <hao.xiang@linux.alibaba.com>
    ---
    arch/x86/include/asm/msr-index.h | 4 ++++
    arch/x86/kvm/x86.c | 25 ++++++++++++++++++++++++-
    2 files changed, 28 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
    index 1d11135..1c8a276 100644
    --- a/arch/x86/include/asm/msr-index.h
    +++ b/arch/x86/include/asm/msr-index.h
    @@ -68,6 +68,10 @@
    #define MSR_PLATFORM_INFO 0x000000ce
    #define MSR_PLATFORM_INFO_CPUID_FAULT_BIT 31
    #define MSR_PLATFORM_INFO_CPUID_FAULT BIT_ULL(MSR_PLATFORM_INFO_CPUID_FAULT_BIT)
    +/* MSR_PLATFORM_INFO bit 15:8, Maximum Non-Turbo Ratio (MAX_NON_TURBO_LIM_RATIO) */
    +#define MSR_PLATFORM_INFO_MAX_NON_TURBO_LIM_RATIO 0x00000000ff00
    +/* MSR_PLATFORM_INFO bit 47:40, Maximum Efficiency Ratio (MAX_EFFICIENCY_RATIO) */
    +#define MSR_PLATFORM_INFO_MAX_EFFICIENCY_RATIO 0xff0000000000

    #define MSR_IA32_UMWAIT_CONTROL 0xe1
    #define MSR_IA32_UMWAIT_CONTROL_C02_DISABLE BIT(0)
    diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
    index c381770..621c3e1 100644
    --- a/arch/x86/kvm/x86.c
    +++ b/arch/x86/kvm/x86.c
    @@ -1679,6 +1679,29 @@ static u64 kvm_get_arch_capabilities(void)
    return data;
    }

    +
    +static u64 kvm_get_msr_platform_info(void)
    +{
    + u64 msr_platform_info = 0;
    +
    + rdmsrl_safe(MSR_PLATFORM_INFO, &msr_platform_info);
    + /*
    + * MSR_PLATFORM_INFO bits:
    + * bit 15:8, Maximum Non-Turbo Ratio (MAX_NON_TURBO_LIM_RATIO)
    + * bit 31, CPUID Faulting Enabled (CPUID_FAULTING_EN)
    + * bit 47:40, Maximum Efficiency Ratio (MAX_EFFICIENCY_RATIO)
    + *
    + * Emulate part msr bits, expose above msr info to guest,
    + * to make sure guest can get correct turbo frequency info.
    + */
    +
    + msr_platform_info &= (MSR_PLATFORM_INFO_MAX_NON_TURBO_LIM_RATIO |
    + MSR_PLATFORM_INFO_MAX_EFFICIENCY_RATIO);
    + msr_platform_info |= MSR_PLATFORM_INFO_CPUID_FAULT;
    +
    + return msr_platform_info;
    +}
    +
    static int kvm_get_msr_feature(struct kvm_msr_entry *msr)
    {
    switch (msr->index) {
    @@ -11919,7 +11942,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
    goto free_guest_fpu;

    vcpu->arch.arch_capabilities = kvm_get_arch_capabilities();
    - vcpu->arch.msr_platform_info = MSR_PLATFORM_INFO_CPUID_FAULT;
    + vcpu->arch.msr_platform_info = kvm_get_msr_platform_info();
    kvm_xen_init_vcpu(vcpu);
    kvm_vcpu_mtrr_init(vcpu);
    vcpu_load(vcpu);
    --
    1.8.3.1
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