diff options
author | Like Xu | 2022-04-11 18:19:36 +0800 |
---|---|---|
committer | Paolo Bonzini | 2022-06-08 04:47:55 -0400 |
commit | c59a1f106f5cd4843c097069ff1bb2ad72103a67 (patch) | |
tree | 6f7a1e7397e411c2137748d5ce699067aad4b6d7 /arch/x86/events | |
parent | 0d23dc34a7cefde5ee25c321949579694edbd16d (diff) |
KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS
If IA32_PERF_CAPABILITIES.PEBS_BASELINE [bit 14] is set, the
IA32_PEBS_ENABLE MSR exists and all architecturally enumerated fixed
and general-purpose counters have corresponding bits in IA32_PEBS_ENABLE
that enable generation of PEBS records. The general-purpose counter bits
start at bit IA32_PEBS_ENABLE[0], and the fixed counter bits start at
bit IA32_PEBS_ENABLE[32].
When guest PEBS is enabled, the IA32_PEBS_ENABLE MSR will be
added to the perf_guest_switch_msr() and atomically switched during
the VMX transitions just like CORE_PERF_GLOBAL_CTRL MSR.
Based on whether the platform supports x86_pmu.pebs_ept, it has also
refactored the way to add more msrs to arr[] in intel_guest_get_msrs()
for extensibility.
Originally-by: Andi Kleen <ak@linux.intel.com>
Co-developed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Co-developed-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Message-Id: <20220411101946.20262-8-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/events')
-rw-r--r-- | arch/x86/events/intel/core.c | 75 |
1 files changed, 57 insertions, 18 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 8c9cb41fc20a..70a5c66789df 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3969,33 +3969,72 @@ static int intel_pmu_hw_config(struct perf_event *event) return 0; } +/* + * Currently, the only caller of this function is the atomic_switch_perf_msrs(). + * The host perf conext helps to prepare the values of the real hardware for + * a set of msrs that need to be switched atomically in a vmx transaction. + * + * For example, the pseudocode needed to add a new msr should look like: + * + * arr[(*nr)++] = (struct perf_guest_switch_msr){ + * .msr = the hardware msr address, + * .host = the value the hardware has when it doesn't run a guest, + * .guest = the value the hardware has when it runs a guest, + * }; + * + * These values have nothing to do with the emulated values the guest sees + * when it uses {RD,WR}MSR, which should be handled by the KVM context, + * specifically in the intel_pmu_{get,set}_msr(). + */ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr, void *data) { struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); struct perf_guest_switch_msr *arr = cpuc->guest_switch_msrs; u64 intel_ctrl = hybrid(cpuc->pmu, intel_ctrl); + u64 pebs_mask = cpuc->pebs_enabled & x86_pmu.pebs_capable; + int global_ctrl, pebs_enable; + + *nr = 0; + global_ctrl = (*nr)++; + arr[global_ctrl] = (struct perf_guest_switch_msr){ + .msr = MSR_CORE_PERF_GLOBAL_CTRL, + .host = intel_ctrl & ~cpuc->intel_ctrl_guest_mask, + .guest = intel_ctrl & (~cpuc->intel_ctrl_host_mask | ~pebs_mask), + }; - arr[0].msr = MSR_CORE_PERF_GLOBAL_CTRL; - arr[0].host = intel_ctrl & ~cpuc->intel_ctrl_guest_mask; - arr[0].guest = intel_ctrl & ~cpuc->intel_ctrl_host_mask; - arr[0].guest &= ~(cpuc->pebs_enabled & x86_pmu.pebs_capable); - *nr = 1; + if (!x86_pmu.pebs) + return arr; - if (x86_pmu.pebs && x86_pmu.pebs_no_isolation) { - /* - * If PMU counter has PEBS enabled it is not enough to - * disable counter on a guest entry since PEBS memory - * write can overshoot guest entry and corrupt guest - * memory. Disabling PEBS solves the problem. - * - * Don't do this if the CPU already enforces it. - */ - arr[1].msr = MSR_IA32_PEBS_ENABLE; - arr[1].host = cpuc->pebs_enabled; - arr[1].guest = 0; - *nr = 2; + /* + * If PMU counter has PEBS enabled it is not enough to + * disable counter on a guest entry since PEBS memory + * write can overshoot guest entry and corrupt guest + * memory. Disabling PEBS solves the problem. + * + * Don't do this if the CPU already enforces it. + */ + if (x86_pmu.pebs_no_isolation) { + arr[(*nr)++] = (struct perf_guest_switch_msr){ + .msr = MSR_IA32_PEBS_ENABLE, + .host = cpuc->pebs_enabled, + .guest = 0, + }; + return arr; } + if (!x86_pmu.pebs_ept) + return arr; + pebs_enable = (*nr)++; + + arr[pebs_enable] = (struct perf_guest_switch_msr){ + .msr = MSR_IA32_PEBS_ENABLE, + .host = cpuc->pebs_enabled & ~cpuc->intel_ctrl_guest_mask, + .guest = pebs_mask & ~cpuc->intel_ctrl_host_mask, + }; + + /* Set hw GLOBAL_CTRL bits for PEBS counter when it runs for guest */ + arr[0].guest |= arr[*nr].guest; + return arr; } |