From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>
Cc: Huang Shijie <shijie@os.amperecomputing.com>,
james.morse@arm.com, suzuki.poulose@arm.com,
yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org,
pbonzini@redhat.com, peterz@infradead.org, ingo@redhat.com,
acme@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, jolsa@kernel.org,
namhyung@kernel.org, irogers@google.com,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-perf-users@vger.kernel.org, patches@amperecomputing.com,
zwang@amperecomputing.com
Subject: Re: [PATCH] perf/core: fix the bug in the event multiplexing
Date: Wed, 9 Aug 2023 09:10:33 +0000 [thread overview]
Message-ID: <ZNNYCQjsi30APZQ+@linux.dev> (raw)
In-Reply-To: <864jl8ha8y.wl-maz@kernel.org>
On Wed, Aug 09, 2023 at 09:48:29AM +0100, Marc Zyngier wrote:
[...]
> Another question is how the same thing is handled on x86? Maybe they
> don't suffer from this problem thanks to specific architectural
> features, but it'd be good to find out, as this may guide the
> implementation in a different way.
I'm pretty sure the bug here is arm64 specific. x86 (at least on intel)
fetches the guest PMU context from the perf driver w/ irqs disabled
immediately before entering the guest (see atomic_switch_perf_msrs()).
--
Thanks,
Oliver
WARNING: multiple messages have this Message-ID (diff)
From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>
Cc: Huang Shijie <shijie@os.amperecomputing.com>,
james.morse@arm.com, suzuki.poulose@arm.com,
yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org,
pbonzini@redhat.com, peterz@infradead.org, ingo@redhat.com,
acme@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, jolsa@kernel.org,
namhyung@kernel.org, irogers@google.com,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-perf-users@vger.kernel.org, patches@amperecomputing.com,
zwang@amperecomputing.com
Subject: Re: [PATCH] perf/core: fix the bug in the event multiplexing
Date: Wed, 9 Aug 2023 09:10:33 +0000 [thread overview]
Message-ID: <ZNNYCQjsi30APZQ+@linux.dev> (raw)
In-Reply-To: <864jl8ha8y.wl-maz@kernel.org>
On Wed, Aug 09, 2023 at 09:48:29AM +0100, Marc Zyngier wrote:
[...]
> Another question is how the same thing is handled on x86? Maybe they
> don't suffer from this problem thanks to specific architectural
> features, but it'd be good to find out, as this may guide the
> implementation in a different way.
I'm pretty sure the bug here is arm64 specific. x86 (at least on intel)
fetches the guest PMU context from the perf driver w/ irqs disabled
immediately before entering the guest (see atomic_switch_perf_msrs()).
--
Thanks,
Oliver
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-08-09 9:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-09 1:39 [PATCH] perf/core: fix the bug in the event multiplexing Huang Shijie
2023-08-09 1:39 ` Huang Shijie
2023-08-09 3:57 ` kernel test robot
2023-08-09 3:57 ` kernel test robot
2023-08-09 8:25 ` Oliver Upton
2023-08-09 8:25 ` Oliver Upton
2023-08-09 9:17 ` Shijie Huang
2023-08-09 9:17 ` Shijie Huang
2023-08-09 9:22 ` Mark Rutland
2023-08-09 9:22 ` Mark Rutland
2023-08-09 9:37 ` Shijie Huang
2023-08-09 9:37 ` Shijie Huang
2023-08-09 8:48 ` Marc Zyngier
2023-08-09 8:48 ` Marc Zyngier
2023-08-09 9:10 ` Oliver Upton [this message]
2023-08-09 9:10 ` Oliver Upton
2023-08-09 9:28 ` Shijie Huang
2023-08-09 9:28 ` Shijie Huang
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