linux-kernel - Re: [PATCH 0/8] perf/amd/ibs: Fix sample period computations

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Message-ID: <ZwYjtkf6E_Pf5opB@google.com>
Date: Tue, 8 Oct 2024 23:33:26 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Ravi Bangoria <ravi.bangoria@....com>
Cc: peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
	eranian@...gle.com, mark.rutland@....com,
	alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
	irogers@...gle.com, adrian.hunter@...el.com,
	kan.liang@...ux.intel.com, tglx@...utronix.de, bp@...en8.de,
	dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	santosh.shukla@....com, ananth.narayan@....com,
	sandipan.das@....com
Subject: Re: [PATCH 0/8] perf/amd/ibs: Fix sample period computations

On Mon, Oct 07, 2024 at 03:48:02AM +0000, Ravi Bangoria wrote:
> IBS Fetch and IBS Op pmus have constraints on supported sample period
> values. The IBS hw behavior could be undefined if they are not followed.
> Currently, IBS driver does not honor them correctly and thus a malicious
> event could cause issues to the system. Fortunately, the IBS hw is very
> resilient so far and IBS pmus are restricted to root only, so the attack
> vector is minimal. In any case, these are genuine bugs and must be fixed.
> 
> Patches are prepared on v6.11.
> 
> Ravi Bangoria (8):
>   perf/amd/ibs: Remove IBS_{FETCH|OP}_CONFIG_MASK macros
>   perf/amd/ibs: Remove pointless sample period check
>   perf/amd/ibs: Fix ->config to sample period calculation for OP pmu
>   perf/amd/ibs: Fix perf_ibs_op.cnt_mask for CurCnt
>   perf/amd/ibs: Don't allow freq mode event creation through ->config
>     interface
>   perf/amd/ibs: Add pmu specific minimum period
>   perf/amd/ibs: Add ->check_period() callback
>   perf/core: Introduce pmu->adjust_period() callback

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

Thanks,
Namhyung

> 
>  arch/x86/events/amd/ibs.c         | 97 +++++++++++++++++++++++--------
>  arch/x86/include/asm/perf_event.h |  1 +
>  include/linux/perf_event.h        |  5 ++
>  kernel/events/core.c              | 12 +++-
>  4 files changed, 88 insertions(+), 27 deletions(-)
> 
> -- 
> 2.46.2
>