From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>, x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Babu Moger <babu.moger@amd.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
David.Kaplan@amd.com, Nikolay Borisov <nik.borisov@suse.com>,
gregkh@linuxfoundation.org, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 03/23] x86/srso: Don't probe microcode in a guest
Date: Fri, 25 Aug 2023 08:52:38 +0100 [thread overview]
Message-ID: <cc4f4937-c696-cb32-939d-bbeafc4210b5@citrix.com> (raw)
In-Reply-To: <3e293282e96b9fe1835c8bd22d1aaac07d9628e7.1692919072.git.jpoimboe@kernel.org>
On 25/08/2023 8:01 am, Josh Poimboeuf wrote:
> To support live migration, the hypervisor sets the "lowest common
> denominator" of features. Probing the microcode isn't allowed because
> any detected features might go away after a migration.
>
> As Andy Cooper states:
>
> "Linux must not probe microcode when virtualised. What it may see
> instantaneously on boot (owing to MSR_PRED_CMD being fully passed
> through) is not accurate for the lifetime of the VM."
>
> Rely on the hypervisor to set the needed IBPB_BRTYPE and SBPB bits.
>
> Fixes: 1b5277c0ea0b ("x86/srso: Add SRSO_NO support")
> Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Thankyou for doing this patch.
next prev parent reply other threads:[~2023-08-25 7:54 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-25 7:01 [PATCH v2 00/23] SRSO fixes/cleanups Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 01/23] x86/srso: Fix srso_show_state() side effect Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 02/23] x86/srso: Set CPUID feature bits independently of bug or mitigation status Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 03/23] x86/srso: Don't probe microcode in a guest Josh Poimboeuf
2023-08-25 7:52 ` Andrew Cooper [this message]
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 04/23] KVM: x86: Add IBPB_BRTYPE support Josh Poimboeuf
2023-08-25 18:15 ` Sean Christopherson
2023-08-26 15:49 ` Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 05/23] KVM: x86: Add SBPB support Josh Poimboeuf
2023-08-25 18:20 ` Sean Christopherson
2023-08-25 7:01 ` [PATCH 06/23] x86/srso: Fix SBPB enablement for spec_rstack_overflow=off Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 07/23] x86/srso: Fix SBPB enablement for (possible) future fixed HW Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 08/23] x86/srso: Print actual mitigation if requested mitigation isn't possible Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 09/23] x86/srso: Print mitigation for retbleed IBPB case Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 10/23] x86/srso: Fix vulnerability reporting for missing microcode Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-09-01 9:40 ` Borislav Petkov
2023-09-02 10:46 ` Ingo Molnar
2023-09-02 17:04 ` Borislav Petkov
2023-09-03 14:37 ` Borislav Petkov
2023-09-05 4:57 ` Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 11/23] x86/srso: Fix unret validation dependencies Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 12/23] x86/alternatives: Remove faulty optimization Josh Poimboeuf
2023-08-25 9:20 ` Ingo Molnar
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 10:27 ` [tip: x86/urgent] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 13/23] x86/srso: Improve i-cache locality for alias mitigation Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 14/23] x86/srso: Unexport untraining functions Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 15/23] x86/srso: Remove 'pred_cmd' label Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 19:51 ` [PATCH 15/23] " Nikolay Borisov
2023-08-26 15:45 ` Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 16/23] x86/bugs: Remove default case for fully switched enums Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-09-02 9:02 ` [PATCH 16/23] " Borislav Petkov
2023-09-05 5:08 ` Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 17/23] x86/srso: Move retbleed IBPB check into existing 'has_microcode' code block Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 18/23] x86/srso: Remove redundant X86_FEATURE_ENTRY_IBPB check Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-09-02 9:10 ` [PATCH 18/23] " Borislav Petkov
2023-08-25 7:01 ` [PATCH 19/23] x86/srso: Disentangle rethunk-dependent options Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 20/23] x86/rethunk: Use SYM_CODE_START[_LOCAL]_NOALIGN macros Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 21/23] x86/retpoline: Remove .text..__x86.return_thunk section Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 22/23] x86/nospec: Refactor UNTRAIN_RET[_*] Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 18:22 ` [PATCH 22/23] " Nikolay Borisov
2023-08-26 15:42 ` Josh Poimboeuf
2023-08-25 7:01 ` [PATCH 23/23] x86/calldepth: Rename __x86_return_skl() to call_depth_return_thunk() Josh Poimboeuf
2023-08-25 10:19 ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-08-25 10:38 ` [PATCH v2 00/23] SRSO fixes/cleanups Ingo Molnar
2023-08-26 15:57 ` Josh Poimboeuf
2023-08-26 17:00 ` Ingo Molnar
2023-10-05 1:29 ` Sean Christopherson
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