From: Oliver Upton <oliver.upton@linux.dev>
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Colton Lewis <coltonlewis@google.com>,
kvm@vger.kernel.org, Sean Christopherson <seanjc@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Will Deacon <will@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Naveen N Rao <naveen@kernel.org>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v6 5/5] perf: Correct perf sampling with guest VMs
Date: Wed, 6 Nov 2024 11:53:07 -0800 [thread overview]
Message-ID: <ZyvJIx-UHXawnUYs@linux.dev> (raw)
In-Reply-To: <007cfed1-111d-45aa-b873-24cca9d4af01@linux.intel.com>
On Wed, Nov 06, 2024 at 11:07:53AM -0500, Liang, Kan wrote:
> > +#ifndef perf_arch_guest_misc_flags
> > +static inline unsigned long perf_arch_guest_misc_flags(struct pt_regs *regs)
> > +{
> > + unsigned long guest_state = perf_guest_state();
> > +
> > + if (guest_state & PERF_GUEST_USER)
> > + return PERF_RECORD_MISC_GUEST_USER;
> > +
> > + if (guest_state & PERF_GUEST_ACTIVE)
> > + return PERF_RECORD_MISC_GUEST_KERNEL;
>
> Is there by any chance to add a PERF_GUEST_KERNEL flag in KVM?
Why do we need another flag? As it stands today, the vCPU is either in
user mode or kernel mode.
> The PERF_GUEST_ACTIVE flag check looks really confusing.
Perhaps instead:
static inline unsigned long perf_arch_guest_misc_flags(struct pt_regs *regs)
{
unsigned long guest_state = perf_guest_state();
if (!(guest_state & PERF_GUEST_ACTIVE))
return 0;
return (guest_state & PERF_GUEST_USER) ? PERF_RECORD_MISC_GUEST_USER :
PERF_RECORD_MISC_GUEST_KERNEL;
}
--
Thanks,
Oliver
next prev parent reply other threads:[~2024-11-06 19:53 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-05 19:55 [PATCH v6 0/5] Correct perf sampling with Guest VMs Colton Lewis
2024-11-05 19:55 ` [PATCH v6 1/5] arm: perf: Drop unused functions Colton Lewis
2024-11-07 11:27 ` Will Deacon
2024-11-05 19:55 ` [PATCH v6 2/5] perf: Hoist perf_instruction_pointer() and perf_misc_flags() Colton Lewis
2024-11-05 19:56 ` [PATCH v6 3/5] powerpc: perf: Use perf_arch_instruction_pointer() Colton Lewis
2024-11-05 19:56 ` [PATCH v6 4/5] x86: perf: Refactor misc flag assignments Colton Lewis
2024-11-06 16:03 ` Liang, Kan
2024-11-06 20:02 ` Oliver Upton
2024-11-06 20:33 ` Liang, Kan
2024-11-06 20:51 ` Oliver Upton
2024-11-05 19:56 ` [PATCH v6 5/5] perf: Correct perf sampling with guest VMs Colton Lewis
2024-11-06 16:07 ` Liang, Kan
2024-11-06 19:53 ` Oliver Upton [this message]
2024-11-06 20:38 ` Liang, Kan
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