From: Borislav Petkov <bp@alien8.de>
To: Ashish Kalra <Ashish.Kalra@amd.com>
Cc: tglx@kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com, seanjc@google.com,
peterz@infradead.org, thomas.lendacky@amd.com,
herbert@gondor.apana.org.au, davem@davemloft.net,
ardb@kernel.org, pbonzini@redhat.com, aik@amd.com,
Michael.Roth@amd.com, KPrateek.Nayak@amd.com,
Tycho.Andersen@amd.com, Nathan.Fontenot@amd.com,
ackerleytng@google.com, jackyli@google.com, pgonda@google.com,
rientjes@google.com, jacobhxu@google.com, xin@zytor.com,
pawan.kumar.gupta@linux.intel.com, babu.moger@amd.com,
dyoung@redhat.com, nikunj@amd.com, john.allen@amd.com,
darwi@linutronix.de, linux-kernel@vger.kernel.org,
linux-crypto@vger.kernel.org, kvm@vger.kernel.org,
linux-coco@lists.linux.dev
Subject: Re: [PATCH v11 5/6] x86/sev: Add interface to re-enable RMP optimizations.
Date: Mon, 10 Aug 2026 10:30:34 -0700 [thread overview]
Message-ID: <20260810173034.GAanoKujdd2O4bGfWC@fat_crate.local> (raw)
In-Reply-To: <afc058ce32417dc45e3f7cd9536d0fafafcacb4b.1784844080.git.ashish.kalra@amd.com>
On Mon, Jul 27, 2026 at 07:05:54PM +0000, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
>
> RMPOPT table is a per-CPU table which indicates if 1GB regions of
> physical memory are entirely hypervisor-owned or not.
>
> When performing host memory accesses in hypervisor mode as well as
> non-SNP guest mode, the processor may consult the RMPOPT table to
> potentially skip an RMP access and improve performance.
>
> Normal guest events clear RMP optimizations: pages are converted from
s/clear/disable/
or "prevent RMP optimizations". "clear" sounds weird.
> shared to private as SNP guests are launched, and large pages are split
> and collapsed during guest operation -- both clear the RMPOPT
> optimizations for the affected 1GB regions.
> Conversely, guest pages are
Not "Conversely" but "When guests are torn down" or something to that effect.
> converted back to shared during SNP guest termination, so those regions
> may become eligible for RMPOPT optimization again.
>
> Without some intervention, all RMP optimizations would eventually be
> lost. Add an interface to re-optimize all of physical memory.
>
> The interface uses mod_delayed_work() instead of queue_delayed_work()
> so that the delay timer is reset on each call. This provides proper
> batching semantics: re-optimization runs 10 seconds after the *last*
> VM termination rather than after the first. mod_delayed_work() also
> re-queues work that is already in-flight, so a re-scan request
> during an active scan is not silently dropped.
And I keep wondering what are you even doing here until I saw the next patch.
Just merge the two into a single patch.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2026-08-10 17:31 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-27 19:00 [PATCH v11 0/6] Add RMPOPT support Ashish Kalra
2026-07-27 19:03 ` [PATCH v11 1/6] x86/cpufeatures: Add X86_FEATURE_RMPOPT feature flag Ashish Kalra
2026-07-27 19:01 ` Ashish Kalra
2026-07-27 19:04 ` [PATCH v11 2/6] x86/sev: Disable CPU hotplug while SNP is active Ashish Kalra
2026-07-29 2:15 ` Borislav Petkov
2026-07-29 17:51 ` Kalra, Ashish
2026-07-31 19:35 ` Tom Lendacky
2026-07-31 20:27 ` Kalra, Ashish
2026-07-27 19:04 ` [PATCH v11 3/6] x86/sev: Initialize RMPOPT configuration MSRs Ashish Kalra
2026-07-30 2:07 ` Borislav Petkov
2026-07-30 2:55 ` K Prateek Nayak
2026-07-30 3:39 ` Borislav Petkov
2026-07-30 19:52 ` Kalra, Ashish
2026-07-30 20:00 ` Kalra, Ashish
2026-07-31 0:12 ` Borislav Petkov
2026-07-31 19:43 ` Tom Lendacky
2026-07-27 19:05 ` [PATCH v11 4/6] x86/sev: Add support to perform RMP optimizations asynchronously Ashish Kalra
2026-07-31 5:44 ` Borislav Petkov
2026-07-31 12:37 ` Kalra, Ashish
2026-08-03 18:56 ` Kalra, Ashish
2026-08-03 19:24 ` Borislav Petkov
2026-08-03 19:37 ` Kalra, Ashish
2026-08-03 21:02 ` Borislav Petkov
2026-08-03 21:23 ` Kalra, Ashish
2026-08-03 21:38 ` Borislav Petkov
2026-08-03 22:22 ` Kalra, Ashish
2026-08-05 0:49 ` Borislav Petkov
2026-08-05 2:38 ` Kalra, Ashish
2026-08-05 19:28 ` Borislav Petkov
2026-08-05 21:04 ` Kalra, Ashish
2026-08-05 15:12 ` Dave Hansen
2026-08-05 19:33 ` Borislav Petkov
2026-08-03 21:10 ` Borislav Petkov
2026-07-31 20:14 ` Tom Lendacky
2026-07-27 19:05 ` [PATCH v11 5/6] x86/sev: Add interface to re-enable RMP optimizations Ashish Kalra
2026-08-10 17:30 ` Borislav Petkov [this message]
2026-07-27 19:06 ` [PATCH v11 6/6] KVM: SEV: Perform RMP optimizations on SNP guest shutdown Ashish Kalra
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