From: Peter Zijlstra <peterz@infradead.org>
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>,
Sean Christopherson <seanjc@google.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Jianfeng Gao <jianfeng.gao@intel.com>,
Andrew Cooper <Andrew.Cooper3@citrix.com>
Subject: Re: [PATCH] perf/x86: KVM: Disable vPMU support on hybrid CPUs (host PMUs)
Date: Tue, 31 Jan 2023 11:59:31 +0100 [thread overview]
Message-ID: <Y9j0kwYiqYdQpx28@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <8eda340a-8c5d-a801-54eb-501c44a68d89@linux.intel.com>
On Tue, Jan 24, 2023 at 10:31:00AM -0500, Liang, Kan wrote:
> Yes, and also the CPUID leaf 0x23H support to enumerate the PMU features
> of each types.
Note that this is not enough or even useful. There is nothing that stops
a vCPU from migrating between types at every instruction. There simply
is no relation between a vCPU and a type, so knowing what a type does or
does not support is useless information.
prev parent reply other threads:[~2023-01-31 11:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 0:40 [PATCH] perf/x86: KVM: Disable vPMU support on hybrid CPUs (host PMUs) Sean Christopherson
2023-01-20 14:39 ` Liang, Kan
2023-01-20 17:32 ` Sean Christopherson
2023-01-20 19:55 ` Liang, Kan
2023-01-20 20:34 ` Sean Christopherson
2023-01-20 22:00 ` Liang, Kan
2023-01-24 1:04 ` Andi Kleen
2023-01-24 15:31 ` Liang, Kan
2023-01-31 10:59 ` Peter Zijlstra [this message]
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