Messages in this thread Patch in this message | | | From | Bandan Das <> | Subject | [PATCH v2] perf/x86: descriptive failure messages for PMU init | Date | Wed, 17 Apr 2019 16:30:04 -0400 |
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There's a default warning message that gets printed, however, there are various failure conditions: - a msr read can fail - a msr write can fail - a msr has an unexpected value - all msrs have unexpected values (disable PMU)
Lastly, use %llx to silence checkpatch
Signed-off-by: Bandan Das <bsd@redhat.com> --- v2: Remove virt specific pr_debugs Change the default warning message
arch/x86/events/core.c | 53 +++++++++++++++++++++++++++++++----------- 1 file changed, 40 insertions(+), 13 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 81911e11a15d..52b0893da78b 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -192,9 +192,16 @@ static void release_pmc_hardware(void) {} static bool check_hw_exists(void) { - u64 val, val_fail = -1, val_new= ~0; - int i, reg, reg_fail = -1, ret = 0; - int bios_fail = 0; + u64 val = -1, val_fail = -1, val_new = ~0; + int i, reg = -1, reg_fail = -1, ret = 0; + + enum { + READ_FAIL = 1, + WRITE_FAIL = 2, + PMU_FAIL = 3, + BIOS_FAIL = 4, + }; + int status = 0; int reg_safe = -1; /* @@ -204,10 +211,13 @@ static bool check_hw_exists(void) for (i = 0; i < x86_pmu.num_counters; i++) { reg = x86_pmu_config_addr(i); ret = rdmsrl_safe(reg, &val); - if (ret) + if (ret) { + status = READ_FAIL; goto msr_fail; + } + if (val & ARCH_PERFMON_EVENTSEL_ENABLE) { - bios_fail = 1; + status = BIOS_FAIL; val_fail = val; reg_fail = reg; } else { @@ -218,11 +228,13 @@ static bool check_hw_exists(void) if (x86_pmu.num_counters_fixed) { reg = MSR_ARCH_PERFMON_FIXED_CTR_CTRL; ret = rdmsrl_safe(reg, &val); - if (ret) + if (ret) { + status = READ_FAIL; goto msr_fail; + } for (i = 0; i < x86_pmu.num_counters_fixed; i++) { if (val & (0x03 << i*4)) { - bios_fail = 1; + status = BIOS_FAIL; val_fail = val; reg_fail = reg; } @@ -236,7 +248,7 @@ static bool check_hw_exists(void) */ if (reg_safe == -1) { - reg = reg_safe; + status = PMU_FAIL; goto msr_fail; } @@ -246,18 +258,22 @@ static bool check_hw_exists(void) * (qemu/kvm) that don't trap on the MSR access and always return 0s. */ reg = x86_pmu_event_addr(reg_safe); - if (rdmsrl_safe(reg, &val)) + if (rdmsrl_safe(reg, &val)) { + status = READ_FAIL; goto msr_fail; + } val ^= 0xffffUL; ret = wrmsrl_safe(reg, val); ret |= rdmsrl_safe(reg, &val_new); - if (ret || val != val_new) + if (ret || val != val_new) { + status = WRITE_FAIL; goto msr_fail; + } /* * We still allow the PMU driver to operate: */ - if (bios_fail) { + if (status == BIOS_FAIL) { pr_cont("Broken BIOS detected, complain to your hardware vendor.\n"); pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n", reg_fail, val_fail); @@ -270,8 +286,19 @@ static bool check_hw_exists(void) pr_cont("PMU not available due to virtualization, using software events only.\n"); } else { pr_cont("Broken PMU hardware detected, using software events only.\n"); - pr_err("Failed to access perfctr msr (MSR %x is %Lx)\n", - reg, val_new); + } + switch (status) { + case READ_FAIL: + pr_err("Failed to read perfctr msr (MSR %x)\n", reg); + break; + case WRITE_FAIL: + pr_err("Failed to write perfctr msr (MSR %x, wrote: %llx, read: %llx)\n", + reg, val, val_new); + break; + case PMU_FAIL: + /* fall through for default message */ + default: + pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources.\n"); } return false; -- 2.19.2
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