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| author |   Paolo Bonzini <pbonzini@redhat.com> | 2022-06-01 05:45:17 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-06-08 13:06:15 -0400 |
| commit | 916e3a4f950eac92c28cc138c10d86514ffebf98 (patch) | |
| tree | 03b3058f7a16c36027dafb72fe86c69c027da3b6 | |
| parent | perf/x86/intel: Fix the comment about guest LBR support on KVM (diff) | |
| download | linux-dev-916e3a4f950eac92c28cc138c10d86514ffebf98.tar.xz linux-dev-916e3a4f950eac92c28cc138c10d86514ffebf98.zip | |
x86: events: Do not return bogus capabilities if PMU is broken
If the PMU is broken due to firmware issues, check_hw_exists() will return
false but perf_get_x86_pmu_capability() will still return data from x86_pmu.
Likewise if some of the hotplug callbacks cannot be installed the contents
of x86_pmu will not be reverted.
Handle the failure in both cases by clearing x86_pmu if init_hw_perf_events()
or reverts to software events only.
Co-developed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/events/core.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 2e16c268a005..f969410d0c90 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2103,14 +2103,15 @@ static int __init init_hw_perf_events(void) } if (err != 0) { pr_cont("no PMU driver, software events only.\n"); - return 0; + err = 0; + goto out_bad_pmu; } pmu_check_apic(); /* sanity check that the hardware exists or is emulated */ if (!check_hw_exists(&pmu, x86_pmu.num_counters, x86_pmu.num_counters_fixed)) - return 0; + goto out_bad_pmu; pr_cont("%s PMU driver.\n", x86_pmu.name); @@ -2219,6 +2220,8 @@ out1: cpuhp_remove_state(CPUHP_AP_PERF_X86_STARTING); out: cpuhp_remove_state(CPUHP_PERF_X86_PREPARE); +out_bad_pmu: + memset(&x86_pmu, 0, sizeof(x86_pmu)); return err; } early_initcall(init_hw_perf_events); @@ -2990,6 +2993,11 @@ unsigned long perf_misc_flags(struct pt_regs *regs) void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap) { + if (!x86_pmu_initialized()) { + memset(cap, 0, sizeof(*cap)); + return; + } + cap->version = x86_pmu.version; /* * KVM doesn't support the hybrid PMU yet. |