From: James Clark james.clark@arm.com
Currently the userspace and kernel filters for guests are never set, so no trace will be generated for them. Add support for tracing guests by passing the desired TRFCR value to KVM so it can be applied to the guest.
By writing either E1TRE or E0TRE, filtering on either guest kernel or guest userspace is also supported. And if both E1TRE and E0TRE are cleared when exclude_guest is set, that option is supported too. This change also brings exclude_host support which is difficult to add as a separate commit without excess churn and resulting in no trace at all.
cpu_prohibit_trace() gets moved to TRBE because the ETM driver doesn't need the read, it already has the base TRFCR value. TRBE only needs the read to disable it and then restore.
Testing =======
The addresses were counted with the following:
$ perf report -D | grep -Eo 'EL2|EL1|EL0' | sort | uniq -c
Guest kernel only:
$ perf record -e cs_etm//Gk -a -- true 535 EL1 1 EL2
Guest user only (only 5 addresses because the guest runs slowly in the model):
$ perf record -e cs_etm//Gu -a -- true 5 EL0
Host kernel only:
$ perf record -e cs_etm//Hk -a -- true 3501 EL2
Host userspace only:
$ perf record -e cs_etm//Hu -a -- true 408 EL0 1 EL2
Signed-off-by: James Clark james.clark@arm.com --- .../coresight/coresight-etm4x-core.c | 49 ++++++++++++++++--- drivers/hwtracing/coresight/coresight-etm4x.h | 2 +- drivers/hwtracing/coresight/coresight-priv.h | 3 ++ .../coresight/coresight-self-hosted-trace.h | 9 ---- drivers/hwtracing/coresight/coresight-trbe.c | 10 ++++ 5 files changed, 56 insertions(+), 17 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index dd8c74f893db..fbc4aa378527 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -6,6 +6,7 @@ #include <linux/acpi.h> #include <linux/bitops.h> #include <linux/kernel.h> +#include <linux/kvm_host.h> #include <linux/moduleparam.h> #include <linux/init.h> #include <linux/types.h> @@ -268,10 +269,28 @@ struct etm4_enable_arg { */ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) { + u64 trfcr; + /* If the CPU doesn't support FEAT_TRF, nothing to do */ if (!drvdata->trfcr) return; - cpu_prohibit_trace(); + + trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); + + write_trfcr(trfcr); + kvm_tracing_set_el1_configuration(trfcr); +} + +static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata) +{ + u64 trfcr = drvdata->trfcr; + + if (drvdata->config.mode & ETM_MODE_EXCL_KERN) + trfcr &= ~TRFCR_ELx_ExTRE; + if (drvdata->config.mode & ETM_MODE_EXCL_USER) + trfcr &= ~TRFCR_ELx_E0TRE; + + return trfcr; }
/* @@ -286,18 +305,28 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) */ static void etm4x_allow_trace(struct etmv4_drvdata *drvdata) { - u64 trfcr = drvdata->trfcr; + u64 trfcr, guest_trfcr;
/* If the CPU doesn't support FEAT_TRF, nothing to do */ - if (!trfcr) + if (!drvdata->trfcr) return;
- if (drvdata->config.mode & ETM_MODE_EXCL_KERN) - trfcr &= ~TRFCR_ELx_ExTRE; - if (drvdata->config.mode & ETM_MODE_EXCL_USER) - trfcr &= ~TRFCR_ELx_E0TRE; + if (drvdata->config.mode & ETM_MODE_EXCL_HOST) + trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); + else + trfcr = etm4x_get_kern_user_filter(drvdata);
write_trfcr(trfcr); + + /* Set filters for guests and pass to KVM */ + if (drvdata->config.mode & ETM_MODE_EXCL_GUEST) + guest_trfcr = drvdata->trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE); + else + guest_trfcr = etm4x_get_kern_user_filter(drvdata); + + /* TRFCR_EL1 doesn't have CX so mask it out. */ + guest_trfcr &= ~TRFCR_EL2_CX; + kvm_tracing_set_el1_configuration(guest_trfcr); }
#ifdef CONFIG_ETM4X_IMPDEF_FEATURE @@ -655,6 +684,12 @@ static int etm4_parse_event_config(struct coresight_device *csdev, if (attr->exclude_user) config->mode = ETM_MODE_EXCL_USER;
+ if (attr->exclude_host) + config->mode |= ETM_MODE_EXCL_HOST; + + if (attr->exclude_guest) + config->mode |= ETM_MODE_EXCL_GUEST; + /* Always start from the default config */ etm4_set_default_config(config);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index 9e9165f62e81..1119762b5cec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -817,7 +817,7 @@ enum etm_impdef_type { * @s_ex_level: Secure ELs where tracing is supported. */ struct etmv4_config { - u32 mode; + u64 mode; u32 pe_sel; u32 cfg; u32 eventctrl0; diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 05f891ca6b5c..76403530f33e 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -42,6 +42,9 @@ extern const struct device_type coresight_dev_type[];
#define ETM_MODE_EXCL_KERN BIT(30) #define ETM_MODE_EXCL_USER BIT(31) +#define ETM_MODE_EXCL_HOST BIT(32) +#define ETM_MODE_EXCL_GUEST BIT(33) + struct cs_pair_attribute { struct device_attribute attr; u32 lo_off; diff --git a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h index 53840a2c41f2..303d71911870 100644 --- a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h +++ b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h @@ -21,13 +21,4 @@ static inline void write_trfcr(u64 val) isb(); }
-static inline u64 cpu_prohibit_trace(void) -{ - u64 trfcr = read_trfcr(); - - /* Prohibit tracing at EL0 & the kernel EL */ - write_trfcr(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE)); - /* Return the original value of the TRFCR */ - return trfcr; -} #endif /* __CORESIGHT_SELF_HOSTED_TRACE_H */ diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index a728802d2206..d6eb0d525a4d 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -1113,6 +1113,16 @@ static bool is_perf_trbe(struct perf_output_handle *handle) return true; }
+static u64 cpu_prohibit_trace(void) +{ + u64 trfcr = read_trfcr(); + + /* Prohibit tracing at EL0 & the kernel EL */ + write_trfcr(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE)); + /* Return the original value of the TRFCR */ + return trfcr; +} + static irqreturn_t arm_trbe_irq_handler(int irq, void *dev) { struct perf_output_handle **handle_ptr = dev;