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 v2 2/7] x86/sev: add support for enabling RMPOPT
Date: Mon, 2 Mar 2026 15:00:08 -0800 [thread overview]
Message-ID: <86bcca73-0c1b-405f-a72d-debb3c696333@intel.com> (raw)
In-Reply-To: <6a50d050-f602-43fd-a44a-cecedd9823eb@amd.com>
On 3/2/26 14:55, Kalra, Ashish wrote:
>> What's wrong with:
>>
>> u64 rmpopt_base = pa_start | MSR_AMD64_RMPOPT_ENABLE;
>> ...
>> for_each_online_cpu(cpu)
>> wrmsrq_on_cpu(cpu, MSR_AMD64_RMPOPT_BASE, rmpopt_base);
>>
>> Then there's at least no ugly casting.
>>
> RMOPT_BASE MSRs don't need to be set serially, therefore, by
> using the cpu_online_mask and on_each_cpu_mask(), we can setup the MSRs
> concurrently and in parallel. Using for_each_online_cpu() will be slower than
> doing on_each_cpu_mask() as it doesn't send IPIs in parallel, right.
If that's the case and you *need* performance, then please go add a
wrmsrq_on_cpumask() function to do things in parallel.
next prev parent reply other threads:[~2026-03-02 23:00 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-02 21:35 [PATCH v2 0/7] Add RMPOPT support Ashish Kalra
2026-03-02 21:35 ` [PATCH v2 1/7] x86/cpufeatures: Add X86_FEATURE_AMD_RMPOPT feature flag Ashish Kalra
2026-03-02 23:00 ` Dave Hansen
2026-03-05 12:36 ` Borislav Petkov
2026-03-02 21:35 ` [PATCH v2 2/7] x86/sev: add support for enabling RMPOPT Ashish Kalra
2026-03-02 22:32 ` Dave Hansen
2026-03-02 22:55 ` Kalra, Ashish
2026-03-02 23:00 ` Dave Hansen [this message]
2026-03-02 23:11 ` Kalra, Ashish
2026-03-02 22:33 ` Dave Hansen
2026-03-06 15:18 ` Borislav Petkov
2026-03-06 15:33 ` Tom Lendacky
2026-03-02 21:36 ` [PATCH v2 3/7] x86/sev: add support for RMPOPT instruction Ashish Kalra
2026-03-02 22:57 ` Dave Hansen
2026-03-02 23:09 ` Kalra, Ashish
2026-03-02 23:15 ` Dave Hansen
2026-03-04 15:56 ` Andrew Cooper
2026-03-04 16:03 ` Dave Hansen
2026-03-25 21:53 ` Kalra, Ashish
2026-03-26 0:40 ` Andrew Cooper
2026-03-26 2:02 ` Kalra, Ashish
2026-03-26 2:14 ` Kalra, Ashish
2026-03-04 15:01 ` Sean Christopherson
2026-03-04 15:25 ` Dave Hansen
2026-03-04 15:32 ` Dave Hansen
2026-03-05 1:40 ` Kalra, Ashish
2026-03-05 19:22 ` Kalra, Ashish
2026-03-05 19:40 ` Dave Hansen
2026-03-11 21:24 ` Kalra, Ashish
2026-03-11 22:20 ` Dave Hansen
2026-03-16 19:03 ` Kalra, Ashish
2026-03-18 14:00 ` Dave Hansen
2026-03-02 21:36 ` [PATCH v2 4/7] x86/sev: Add interface to re-enable RMP optimizations Ashish Kalra
2026-03-02 21:36 ` [PATCH v2 5/7] KVM: guest_memfd: Add cleanup interface for guest teardown Ashish Kalra
2026-03-09 9:01 ` Ackerley Tng
2026-03-10 22:18 ` Kalra, Ashish
2026-03-11 6:00 ` Ackerley Tng
2026-03-11 21:49 ` Kalra, Ashish
2026-03-27 17:16 ` Ackerley Tng
2026-03-31 4:45 ` Kalra, Ashish
2026-03-02 21:37 ` [PATCH v2 6/7] KVM: SEV: Implement SEV-SNP specific guest cleanup Ashish Kalra
2026-03-02 21:37 ` [PATCH v2 7/7] x86/sev: Add debugfs support for RMPOPT Ashish Kalra
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