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From: Kim Phillips <kim.phillips@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: <linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>,
	<linux-coco@lists.linux.dev>, <x86@kernel.org>,
	Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Nikunj A Dadhania <nikunj@amd.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Michael Roth <michael.roth@amd.com>,
	Naveen Rao <naveen.rao@amd.com>,
	David Kaplan <david.kaplan@amd.com>,
	Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v4 01/10] x86/bugs: Only log missing retpoline when it's actually the missing mitigation
Date: Thu, 6 Aug 2026 15:12:12 -0500	[thread overview]
Message-ID: <9e5183be-1f31-4f6a-8b91-0f9a92590241@amd.com> (raw)
In-Reply-To: <20260805224907.GDanO942iYDbai1kFx@fat_crate.local>

On 8/5/26 5:49 PM, Borislav Petkov wrote:
> On Wed, Aug 05, 2026 at 09:51:11AM -0500, Kim Phillips wrote:
>> This patch corrects code that already cares about RETPOLINE=n kernels, but
>> it's also useful if you know all the target systems for a RETPOLINE=n config have
>> alternatives to RETPOLINE, such as {,e,Auto}IBRS.  This will become more and more
>> true as time goes by.
> Why would more and more configs become relevant which disable
> CONFIG_MITIGATION_RETPOLINE?
>
> What is the compelling use case which warrants to have this in the upstream
> kernel?
If by 'this' you mean this patch, it's because it fixes a bug with 
RETPOLINE=n kernels that sashiko found when reviewing the rest of the 
patches in the series.

If by 'this' you mean RETPOLINE=n configurability in general, this patch 
isn't adding or removing that.

Thanks,

Kim

  reply	other threads:[~2026-08-06 20:12 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-04 23:56 [PATCH v4 00/10] KVM: SEV: Add support for IBPB-on-Entry and BTB Isolation Kim Phillips
2026-08-04 23:56 ` [PATCH v4 01/10] x86/bugs: Only log missing retpoline when it's actually the missing mitigation Kim Phillips
2026-08-05  0:44   ` Borislav Petkov
2026-08-05 14:51     ` Kim Phillips
2026-08-05 22:49       ` Borislav Petkov
2026-08-06 20:12         ` Kim Phillips [this message]
2026-08-07  5:44           ` Borislav Petkov
2026-08-10 23:21             ` Kim Phillips
2026-08-11  0:48               ` Borislav Petkov
2026-08-04 23:56 ` [PATCH v4 02/10] cpu/bugs: Allow forcing Automatic IBRS with SNP active using spectre_v2=eibrs Kim Phillips
2026-08-18 23:22   ` Borislav Petkov
2026-08-26 22:52     ` Kim Phillips
2026-08-19  0:12   ` Pawan Gupta
2026-08-26 23:05     ` Kim Phillips
2026-08-04 23:56 ` [PATCH v4 03/10] cpu/bugs: Fall back to AutoIBRS when retpoline unavailable on SNP CPUs Kim Phillips
2026-08-04 23:56 ` [PATCH v4 04/10] cpu/bugs: Allow spectre_v2=ibrs on x86 vendors other than Intel Kim Phillips
2026-08-19  1:17   ` Pawan Gupta
2026-08-26 23:06     ` Kim Phillips
2026-08-04 23:56 ` [PATCH v4 05/10] KVM: SEV: Define SVM_SEV_FEAT_* flags using BIT_ULL() Kim Phillips
2026-08-04 23:56 ` [PATCH v4 06/10] KVM: selftests: sev_init2: Use BIT_ULL for VMSA feature bit definition Kim Phillips
2026-08-04 23:56 ` [PATCH v4 07/10] KVM: SEV: Disallow setting SNP-only features for non-SNP guests via a single mask Kim Phillips
2026-08-04 23:56 ` [PATCH v4 08/10] KVM: SEV: Advertise SVM_SEV_FEAT_SNP_ACTIVE Kim Phillips
2026-08-04 23:56 ` [PATCH v4 09/10] KVM: SEV: Add support for IBPB-on-Entry Kim Phillips
2026-08-04 23:56 ` [PATCH v4 10/10] KVM: SEV: Add support for SNP BTB Isolation Kim Phillips

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