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    Subject[PATCH v5 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching
    Date
    The vCPU lbr event relies on the host to save/restore all the lbr
    related MSRs. So add the LBR_SELECT save/restore to the related
    functions for the vCPU case.

    Signed-off-by: Wei Wang <wei.w.wang@intel.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Andi Kleen <ak@linux.intel.com>
    ---
    arch/x86/events/intel/lbr.c | 7 +++++++
    arch/x86/events/perf_event.h | 1 +
    2 files changed, 8 insertions(+)

    diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
    index 7951b22..740c097 100644
    --- a/arch/x86/events/intel/lbr.c
    +++ b/arch/x86/events/intel/lbr.c
    @@ -383,6 +383,9 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)

    wrmsrl(x86_pmu.lbr_tos, tos);
    task_ctx->lbr_stack_state = LBR_NONE;
    +
    + if (cpuc->vcpu_lbr)
    + wrmsrl(MSR_LBR_SELECT, task_ctx->lbr_sel);
    }

    static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
    @@ -409,6 +412,10 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
    if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
    rdmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
    }
    +
    + if (cpuc->vcpu_lbr)
    + rdmsrl(MSR_LBR_SELECT, task_ctx->lbr_sel);
    +
    task_ctx->valid_lbrs = i;
    task_ctx->tos = tos;
    task_ctx->lbr_stack_state = LBR_VALID;
    diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
    index bbea559..ccd0215 100644
    --- a/arch/x86/events/perf_event.h
    +++ b/arch/x86/events/perf_event.h
    @@ -653,6 +653,7 @@ struct x86_perf_task_context {
    u64 lbr_from[MAX_LBR_ENTRIES];
    u64 lbr_to[MAX_LBR_ENTRIES];
    u64 lbr_info[MAX_LBR_ENTRIES];
    + u64 lbr_sel;
    int tos;
    int valid_lbrs;
    int lbr_callstack_users;
    --
    2.7.4
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