From: Tycho Andersen <tycho@kernel.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Ashish Kalra <ashish.kalra@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
John Allen <john.allen@amd.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Paolo Bonzini <pbonzini@redhat.com>,
Shuah Khan <shuah@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH 3/4] crypto/ccp: support setting RAPL_DIS in SNP_INIT_EX
Date: Mon, 23 Feb 2026 15:14:45 -0700 [thread overview]
Message-ID: <aZzRVXp_E3cMcgtX@tycho.pizza> (raw)
In-Reply-To: <aZyC89v9JAVEPeLt@google.com>
On Mon, Feb 23, 2026 at 08:40:19AM -0800, Sean Christopherson wrote:
> On Mon, Feb 23, 2026, Tycho Andersen wrote:
> > From: "Tycho Andersen (AMD)" <tycho@kernel.org>
> >
> > The kernel allows setting the RAPL_DIS policy bit, but had no way to set
>
> Please actually say what RAPL_DIS is and does, and explain why this is the
> correct approach. I genuinely have no idea what the impact of this patch is,
> (beyond disabling something, obviously).
Sure, the easiest thing is probably to quote the firmware PDF:
Some processors support the Running Average Power Limit (RAPL)
feature which provides information about power utilization of
software. RAPL can be disabled using the RAPL_DIS flag in
SNP_INIT_EX to disable RAPL while SNP firmware is in the INIT
state. Guests may require that RAPL is disabled by using the
POLICY.RAPL_DIS guest policy flag.
I'll add this to the message in the next version.
I will also split out the RAPL_DIS stuff from the test fix for the
firmware update.
Tycho
next prev parent reply other threads:[~2026-02-23 22:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-23 16:28 [PATCH 0/4] Allow setting RAPL_DIS during SNP_INIT_EX Tycho Andersen
2026-02-23 16:28 ` [PATCH 1/4] selftests/kvm: allow retrieving underlying SEV firmware error Tycho Andersen
2026-02-23 16:28 ` [PATCH 2/4] selftests/kvm: check that SEV-ES VMs are allowed in SEV-SNP mode Tycho Andersen
2026-02-23 16:36 ` Sean Christopherson
2026-02-23 16:48 ` Tycho Andersen
2026-02-23 17:15 ` Sean Christopherson
2026-02-23 22:12 ` Tycho Andersen
2026-02-24 18:02 ` Sean Christopherson
2026-02-25 17:29 ` Tycho Andersen
2026-02-25 17:44 ` Sean Christopherson
2026-02-26 20:59 ` Tycho Andersen
2026-02-26 22:28 ` Sean Christopherson
2026-02-23 16:28 ` [PATCH 3/4] crypto/ccp: support setting RAPL_DIS in SNP_INIT_EX Tycho Andersen
2026-02-23 16:40 ` Sean Christopherson
2026-02-23 22:14 ` Tycho Andersen [this message]
2026-02-24 17:50 ` Sean Christopherson
2026-02-25 18:05 ` Tycho Andersen
2026-02-23 16:29 ` [PATCH 4/4] selftests/kvm: smoke test support for RAPL_DIS Tycho Andersen
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