From: Dave Hansen <dave.hansen@intel.com>
To: "Kalra, Ashish" <ashish.kalra@amd.com>,
tglx@kernel.org, mingo@redhat.com, bp@alien8.de,
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
Cc: pbonzini@redhat.com, aik@amd.com, Michael.Roth@amd.com,
KPrateek.Nayak@amd.com, Tycho.Andersen@amd.com,
Nathan.Fontenot@amd.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 0/6] Add RMPOPT support.
Date: Wed, 18 Feb 2026 07:03:56 -0800 [thread overview]
Message-ID: <31b42ba3-dd0c-42e7-ad1e-800c5cd2bcf8@intel.com> (raw)
In-Reply-To: <65986f9e-59e8-4f1c-aaa7-1edf45af24d8@amd.com>
On 2/17/26 20:12, Kalra, Ashish wrote:
>> That's not awful.
>>
>> To be honest, though, I think this is misdesigned. Shouldn't the CPU
>> *boot* in a state where it is optimized? Why should software have to
>> tell it that coming out of reset, there is no SEV-SNP memory?
> When the CPU boots, the RMP checks are not done and therefore the CPU
> is booting in a state where it is optimized.
>
> The RMP checks are not enabled till SEV-SNP is enabled and SNP is enabled
> during kernel boot (as part of iommu_snp_enable() -> snp_rmptable_init()).
>
> Once SNP is enabled as part of kernel boot, hypervisor and non-SNP guests are
> subject to RMP checks on writes to provide integrity of SEV-SNP guest memory.
>
> Therefore, we need to enable these RMP optimizations after SNP has been
> enabled to indicate which 1GB regions of memory are known to not contain any
> SEV-SNP guest memory.
They are known not to contain any SEV-SNP guest memory at the moment
snp_rmptable_init() finishes, no?
next prev parent reply other threads:[~2026-02-18 15:03 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-17 20:09 [PATCH 0/6] Add RMPOPT support Ashish Kalra
2026-02-17 20:09 ` [PATCH 1/6] x86/cpufeatures: Add X86_FEATURE_AMD_RMPOPT feature flag Ashish Kalra
2026-02-17 23:06 ` Ahmed S. Darwish
2026-02-17 20:10 ` [PATCH 2/6] x86/sev: add support for enabling RMPOPT Ashish Kalra
2026-02-17 22:06 ` Dave Hansen
2026-02-18 3:08 ` K Prateek Nayak
2026-02-18 14:59 ` Dave Hansen
2026-02-18 16:55 ` Kalra, Ashish
2026-02-18 17:01 ` Dave Hansen
2026-02-18 17:07 ` Kalra, Ashish
2026-02-18 17:17 ` Dave Hansen
2026-02-18 22:17 ` Kalra, Ashish
2026-02-18 22:56 ` Dave Hansen
2026-02-17 20:10 ` [PATCH 3/6] x86/sev: add support for RMPOPT instruction Ashish Kalra
2026-02-18 16:28 ` Uros Bizjak
2026-02-17 20:11 ` [PATCH 4/6] x86/sev: Add interface to re-enable RMP optimizations Ashish Kalra
2026-02-17 20:11 ` [PATCH 5/6] x86/sev: Use configfs " Ashish Kalra
2026-02-17 22:19 ` Dave Hansen
2026-02-18 3:34 ` Kalra, Ashish
2026-02-18 4:39 ` Kalra, Ashish
2026-02-18 15:10 ` Dave Hansen
2026-02-17 20:11 ` [PATCH 6/6] x86/sev: Add debugfs support for RMPOPT Ashish Kalra
2026-02-17 22:42 ` Ahmed S. Darwish
2026-02-17 22:11 ` [PATCH 0/6] Add RMPOPT support Dave Hansen
2026-02-18 4:12 ` Kalra, Ashish
2026-02-18 15:03 ` Dave Hansen [this message]
2026-02-18 17:03 ` Kalra, Ashish
2026-02-18 17:15 ` Dave Hansen
2026-02-18 21:09 ` Kalra, Ashish
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