linux-kernel - [PATCH 0/5] Perf kvm commands bug fix

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250805004633.135904-1-dapeng1.mi@linux.intel.com>
Date: Tue,  5 Aug 2025 08:46:28 +0800
From: Dapeng Mi <dapeng1.mi@...ux.intel.com>
To: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Kan Liang <kan.liang@...ux.intel.com>
Cc: linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Kevin Tian <kevin.tian@...el.com>,
	Dapeng Mi <dapeng1.mi@...el.com>,
	Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: [PATCH 0/5] Perf kvm commands bug fix

This patch-set fixes perf kvm commands issues, like missed memory
allocation check/free, out of range memory access and especially the
issue that fails to sample guest with "perf kvm record/top" commands on
Intel platforms.

The commit 634d36f82517 ("perf record: Just use "cycles:P" as the
 default event") changes to use PEBS event to do sampling by default
including guest sampling. This breaks host to sample guest with commands
"perf kvm record/top" on Intel platforms.

Since the change "KVM: x86/pmu: Add basic support to enable guest PEBS
 via DS"[1] starts, host loses the capability to sample guest with PEBS
since all PEBS related MSRs are switched to guest value after vm-entry,
like IA32_DS_AREA MSR is switched to guest GVA at vm-entry. This leads
to PEBS events can't be used to sample guest by host, otherwise no guest
PEBS records can be really sampled. The patches 4-5/5 fix this issue by
using "cycles" event instead of PEBS event "cycles:P" to sample guest on
Intel platforms.

Tests:
  * Run command "perf kvm record -a && perf kvm report" and "perf kvm
    top" on Intel Sapphire Rapids platform, guest records can be
    captured successfully.
  * Since no powerpc platforms on hand, doesn't check the patches on
    powerpc. Any test on powerpc is appreciated.

Ref:
  [1] https://lore.kernel.org/all/20220411101946.20262-1-likexu@tencent.com/

Dapeng Mi (5):
  perf tools kvm: Add missed memory allocation check and free
  perf tools kvm: Fix the potential out of range memory access issue
  perf tools: Add helper x86__is_intel_cpu()
  perf tools kvm: Use "cycles" to sample guest for "kvm record" on Intel
  perf tools kvm: Use "cycles" to sample guest for "kvm top" on Intel

 tools/perf/arch/x86/util/kvm-stat.c | 46 ++++++++++++++++++
 tools/perf/builtin-kvm.c            | 73 ++++++++++++++++++++++++-----
 tools/perf/util/env.c               | 22 +++++++++
 tools/perf/util/env.h               |  2 +
 4 files changed, 131 insertions(+), 12 deletions(-)

base-commit: 6235ce77749f45cac27f630337e2fdf04e8a6c73
-- 
2.34.1