[PATCH 0/2] perf intel-pt: Some small fixes

[PATCH 0/2] perf intel-pt: Some small fixes

[Adrian Hunter]

Hi

Here are a couple of small Intel PT fixes.


Adrian Hunter (2):
      perf intel-pt: Fix aux_watermark calculation for 64-bit size
      perf intel-pt: Fix exclude_guest setting

 tools/perf/arch/x86/util/intel-pt.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)


Regards
Adrian

[PATCH 1/2] perf intel-pt: Fix aux_watermark calculation for 64-bit size

[Adrian Hunter]

aux_watermark is a u32. For a 64-bit size, cap the aux_watermark
calculation at UINT_MAX instead of truncating it to 32-bits.

Fixes: 874fc35cdd55 ("perf intel-pt: Use aux_watermark")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/arch/x86/util/intel-pt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c
index 6de7e2d21075..c8fa15f280d2 100644
--- a/tools/perf/arch/x86/util/intel-pt.c
+++ b/tools/perf/arch/x86/util/intel-pt.c
@@ -758,7 +758,8 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 	}
 
 	if (!opts->auxtrace_snapshot_mode && !opts->auxtrace_sample_mode) {
-		u32 aux_watermark = opts->auxtrace_mmap_pages * page_size / 4;
+		size_t aw = opts->auxtrace_mmap_pages * (size_t)page_size / 4;
+		u32 aux_watermark = aw > UINT_MAX ? UINT_MAX : aw;
 
 		intel_pt_evsel->core.attr.aux_watermark = aux_watermark;
 	}
-- 
2.34.1

[PATCH 2/2] perf intel-pt: Fix exclude_guest setting

[Adrian Hunter]

In the past, the exclude_guest setting has had no effect on Intel PT
tracing, but that may not be the case in the future.

Set the flag correctly based upon whether KVM is using Intel PT
"Host/Guest" mode, which is determined by the kvm_intel module
parameter pt_mode:

 pt_mode=0	System-wide mode : host and guest output to host buffer
 pt_mode=1	Host/Guest mode : host/guest output to host/guest
                buffers respectively

Fixes: 6e86bfdc4a60 ("perf intel-pt: Support decoding of guest kernel")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/arch/x86/util/intel-pt.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c
index c8fa15f280d2..4b710e875953 100644
--- a/tools/perf/arch/x86/util/intel-pt.c
+++ b/tools/perf/arch/x86/util/intel-pt.c
@@ -32,6 +32,7 @@
 #include "../../../util/tsc.h"
 #include <internal/lib.h> // page_size
 #include "../../../util/intel-pt.h"
+#include <api/fs/fs.h>
 
 #define KiB(x) ((x) * 1024)
 #define MiB(x) ((x) * 1024 * 1024)
@@ -428,6 +429,16 @@ static int intel_pt_track_switches(struct evlist *evlist)
 }
 #endif
 
+static bool intel_pt_exclude_guest(void)
+{
+	int pt_mode;
+
+	if (sysfs__read_int("module/kvm_intel/parameters/pt_mode", &pt_mode))
+		pt_mode = 0;
+
+	return pt_mode == 1;
+}
+
 static void intel_pt_valid_str(char *str, size_t len, u64 valid)
 {
 	unsigned int val, last = 0, state = 1;
@@ -620,6 +631,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 			}
 			evsel->core.attr.freq = 0;
 			evsel->core.attr.sample_period = 1;
+			evsel->core.attr.exclude_guest = intel_pt_exclude_guest();
 			evsel->no_aux_samples = true;
 			evsel->needs_auxtrace_mmap = true;
 			intel_pt_evsel = evsel;
-- 
2.34.1

Re: [PATCH 0/2] perf intel-pt: Some small fixes

[Namhyung Kim]

On Tue, Jun 25, 2024 at 01:45:30PM +0300, Adrian Hunter wrote:
> Hi
> 
> Here are a couple of small Intel PT fixes.
> 
> 
> Adrian Hunter (2):
>       perf intel-pt: Fix aux_watermark calculation for 64-bit size
>       perf intel-pt: Fix exclude_guest setting

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> 
>  tools/perf/arch/x86/util/intel-pt.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> 
> Regards
> Adrian

Re: [PATCH 0/2] perf intel-pt: Some small fixes

[Namhyung Kim]

On Tue, 25 Jun 2024 13:45:30 +0300, Adrian Hunter wrote:

> Here are a couple of small Intel PT fixes.
> 
> 
> Adrian Hunter (2):
>       perf intel-pt: Fix aux_watermark calculation for 64-bit size
>       perf intel-pt: Fix exclude_guest setting
> 
> [...]

Applied to perf-tools-next, thanks!

Best regards,
Namhyung