diff options
Diffstat (limited to 'arch/x86/events/intel/core.c')
| -rw-r--r-- | arch/x86/events/intel/core.c | 160 |
1 files changed, 131 insertions, 29 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index bd8b98857609..2db93498ff71 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -14,6 +14,7 @@ #include <linux/slab.h> #include <linux/export.h> #include <linux/nmi.h> +#include <linux/kvm_host.h> #include <asm/cpufeature.h> #include <asm/hardirq.h> @@ -2852,6 +2853,47 @@ static void intel_pmu_reset(void) local_irq_restore(flags); } +/* + * We may be running with guest PEBS events created by KVM, and the + * PEBS records are logged into the guest's DS and invisible to host. + * + * In the case of guest PEBS overflow, we only trigger a fake event + * to emulate the PEBS overflow PMI for guest PEBS counters in KVM. + * The guest will then vm-entry and check the guest DS area to read + * the guest PEBS records. + * + * The contents and other behavior of the guest event do not matter. + */ +static void x86_pmu_handle_guest_pebs(struct pt_regs *regs, + struct perf_sample_data *data) +{ + struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); + u64 guest_pebs_idxs = cpuc->pebs_enabled & ~cpuc->intel_ctrl_host_mask; + struct perf_event *event = NULL; + int bit; + + if (!unlikely(perf_guest_state())) + return; + + if (!x86_pmu.pebs_ept || !x86_pmu.pebs_active || + !guest_pebs_idxs) + return; + + for_each_set_bit(bit, (unsigned long *)&guest_pebs_idxs, + INTEL_PMC_IDX_FIXED + x86_pmu.num_counters_fixed) { + event = cpuc->events[bit]; + if (!event->attr.precise_ip) + continue; + + perf_sample_data_init(data, 0, event->hw.last_period); + if (perf_event_overflow(event, data, regs)) + x86_pmu_stop(event, 0); + + /* Inject one fake event is enough. */ + break; + } +} + static int handle_pmi_common(struct pt_regs *regs, u64 status) { struct perf_sample_data data; @@ -2891,10 +2933,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) * counters from the GLOBAL_STATUS mask and we always process PEBS * events via drain_pebs(). */ - if (x86_pmu.flags & PMU_FL_PEBS_ALL) - status &= ~cpuc->pebs_enabled; - else - status &= ~(cpuc->pebs_enabled & PEBS_COUNTER_MASK); + status &= ~(cpuc->pebs_enabled & x86_pmu.pebs_capable); /* * PEBS overflow sets bit 62 in the global status register @@ -2903,6 +2942,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status) u64 pebs_enabled = cpuc->pebs_enabled; handled++; + x86_pmu_handle_guest_pebs(regs, &data); x86_pmu.drain_pebs(regs, &data); status &= intel_ctrl | GLOBAL_STATUS_TRACE_TOPAPMI; @@ -3930,40 +3970,98 @@ static int intel_pmu_hw_config(struct perf_event *event) return 0; } -static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr) +/* + * 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; + struct kvm_pmu *kvm_pmu = (struct kvm_pmu *)data; 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; - if (x86_pmu.flags & PMU_FL_PEBS_ALL) - arr[0].guest &= ~cpuc->pebs_enabled; - else - arr[0].guest &= ~(cpuc->pebs_enabled & PEBS_COUNTER_MASK); - *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 (!kvm_pmu || !x86_pmu.pebs_ept) + return arr; + + arr[(*nr)++] = (struct perf_guest_switch_msr){ + .msr = MSR_IA32_DS_AREA, + .host = (unsigned long)cpuc->ds, + .guest = kvm_pmu->ds_area, + }; + + if (x86_pmu.intel_cap.pebs_baseline) { + arr[(*nr)++] = (struct perf_guest_switch_msr){ + .msr = MSR_PEBS_DATA_CFG, + .host = cpuc->pebs_data_cfg, + .guest = kvm_pmu->pebs_data_cfg, + }; + } + + 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, + }; + + if (arr[pebs_enable].host) { + /* Disable guest PEBS if host PEBS is enabled. */ + arr[pebs_enable].guest = 0; + } else { + /* Disable guest PEBS for cross-mapped PEBS counters. */ + arr[pebs_enable].guest &= ~kvm_pmu->host_cross_mapped_mask; + /* Set hw GLOBAL_CTRL bits for PEBS counter when it runs for guest */ + arr[global_ctrl].guest |= arr[pebs_enable].guest; } return arr; } -static struct perf_guest_switch_msr *core_guest_get_msrs(int *nr) +static struct perf_guest_switch_msr *core_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; @@ -5650,6 +5748,7 @@ __init int intel_pmu_init(void) x86_pmu.events_mask_len = eax.split.mask_length; x86_pmu.max_pebs_events = min_t(unsigned, MAX_PEBS_EVENTS, x86_pmu.num_counters); + x86_pmu.pebs_capable = PEBS_COUNTER_MASK; /* * Quirk: v2 perfmon does not report fixed-purpose events, so @@ -5834,6 +5933,7 @@ __init int intel_pmu_init(void) x86_pmu.pebs_aliases = NULL; x86_pmu.pebs_prec_dist = true; x86_pmu.lbr_pt_coexist = true; + x86_pmu.pebs_capable = ~0ULL; x86_pmu.flags |= PMU_FL_HAS_RSP_1; x86_pmu.flags |= PMU_FL_PEBS_ALL; x86_pmu.get_event_constraints = glp_get_event_constraints; @@ -6138,6 +6238,7 @@ __init int intel_pmu_init(void) case INTEL_FAM6_ICELAKE_X: case INTEL_FAM6_ICELAKE_D: + x86_pmu.pebs_ept = 1; pmem = true; fallthrough; case INTEL_FAM6_ICELAKE_L: @@ -6190,6 +6291,7 @@ __init int intel_pmu_init(void) x86_pmu.pebs_aliases = NULL; x86_pmu.pebs_prec_dist = true; x86_pmu.pebs_block = true; + x86_pmu.pebs_capable = ~0ULL; x86_pmu.flags |= PMU_FL_HAS_RSP_1; x86_pmu.flags |= PMU_FL_NO_HT_SHARING; x86_pmu.flags |= PMU_FL_PEBS_ALL; @@ -6235,6 +6337,7 @@ __init int intel_pmu_init(void) x86_pmu.pebs_aliases = NULL; x86_pmu.pebs_prec_dist = true; x86_pmu.pebs_block = true; + x86_pmu.pebs_capable = ~0ULL; x86_pmu.flags |= PMU_FL_HAS_RSP_1; x86_pmu.flags |= PMU_FL_NO_HT_SHARING; x86_pmu.flags |= PMU_FL_PEBS_ALL; @@ -6399,8 +6502,7 @@ __init int intel_pmu_init(void) x86_pmu.intel_ctrl); /* * Access LBR MSR may cause #GP under certain circumstances. - * E.g. KVM doesn't support LBR MSR - * Check all LBT MSR here. + * Check all LBR MSR here. * Disable LBR access if any LBR MSRs can not be accessed. */ if (x86_pmu.lbr_tos && !check_msr(x86_pmu.lbr_tos, 0x3UL)) |