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    Subject[PATCH v7 05/13] perf/x86/intel/pt: Introduce a new function to get capability of Intel PT
    Date
    New function __pt_cap_get() will be invoked in KVM to check
    if a specific capability is availiable in KVM guest.
    Another function pt_cap_get() can only check the hardware
    capabilities but this may different with KVM guest because
    some features may not be exposed to guest.

    Signed-off-by: Luwei Kang <luwei.kang@intel.com>
    ---
    arch/x86/events/intel/pt.c | 10 ++++++++--
    arch/x86/include/asm/intel_pt.h | 2 ++
    2 files changed, 10 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
    index d5819a2..a1fe6ff 100644
    --- a/arch/x86/events/intel/pt.c
    +++ b/arch/x86/events/intel/pt.c
    @@ -76,14 +76,20 @@
    PT_CAP(psb_periods, 1, CPUID_EBX, 0xffff0000),
    };

    -u32 pt_cap_get(enum pt_capabilities cap)
    +u32 __pt_cap_get(u32 *caps, enum pt_capabilities cap)
    {
    struct pt_cap_desc *cd = &pt_caps[cap];
    - u32 c = pt_pmu.caps[cd->leaf * PT_CPUID_REGS_NUM + cd->reg];
    + u32 c = caps[cd->leaf * PT_CPUID_REGS_NUM + cd->reg];
    unsigned int shift = __ffs(cd->mask);

    return (c & cd->mask) >> shift;
    }
    +EXPORT_SYMBOL_GPL(__pt_cap_get);
    +
    +u32 pt_cap_get(enum pt_capabilities cap)
    +{
    + return __pt_cap_get(pt_pmu.caps, cap);
    +}
    EXPORT_SYMBOL_GPL(pt_cap_get);

    static ssize_t pt_cap_show(struct device *cdev,
    diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h
    index 2de4db0..3a4f524 100644
    --- a/arch/x86/include/asm/intel_pt.h
    +++ b/arch/x86/include/asm/intel_pt.h
    @@ -27,9 +27,11 @@ enum pt_capabilities {
    #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
    void cpu_emergency_stop_pt(void);
    extern u32 pt_cap_get(enum pt_capabilities cap);
    +extern u32 __pt_cap_get(u32 *caps, enum pt_capabilities cap);
    #else
    static inline void cpu_emergency_stop_pt(void) {}
    static inline u32 pt_cap_get(enum pt_capabilities cap) { return 0; }
    +static u32 __pt_cap_get(u32 *caps, enum pt_capabilities cap) { return 0; }
    #endif

    #endif /* _ASM_X86_INTEL_PT_H */
    --
    1.8.3.1
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