From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, amit@kernel.org,
kvm@vger.kernel.org, amit.shah@amd.com, thomas.lendacky@amd.com,
bp@alien8.de, tglx@linutronix.de, peterz@infradead.org,
corbet@lwn.net, mingo@redhat.com, dave.hansen@linux.intel.com,
hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com,
daniel.sneddon@linux.intel.com, kai.huang@intel.com,
sandipan.das@amd.com, boris.ostrovsky@oracle.com,
Babu.Moger@amd.com, david.kaplan@amd.com, dwmw@amazon.co.uk,
andrew.cooper3@citrix.com
Subject: Re: [PATCH 1/2] x86/bugs: Don't fill RSB on VMEXIT with eIBRS+retpoline
Date: Wed, 20 Nov 2024 10:12:38 -0800 [thread overview]
Message-ID: <20241120181238.n3xwpd6uticlaw4a@desk> (raw)
In-Reply-To: <2e062b6c142bb3770a0829e2cf21e11e8fb6ae5c.1732087270.git.jpoimboe@kernel.org>
On Tue, Nov 19, 2024 at 11:27:50PM -0800, Josh Poimboeuf wrote:
> eIBRS protects against RSB underflow/poisoning attacks. Adding
> retpoline to the mix doesn't change that. Retpoline has a balanced
> CALL/RET anyway.
>
> So the current full RSB filling on VMEXIT with eIBRS+retpoline is
> overkill. Disable it (or do the VMEXIT_LITE mitigation if needed).
>
> Suggested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
next prev parent reply other threads:[~2024-11-20 18:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-20 7:27 [PATCH 0/2] x86/bugs: RSB tweaks Josh Poimboeuf
2024-11-20 7:27 ` [PATCH 1/2] x86/bugs: Don't fill RSB on VMEXIT with eIBRS+retpoline Josh Poimboeuf
2024-11-20 18:12 ` Pawan Gupta [this message]
2024-11-20 7:27 ` [PATCH 2/2] x86/bugs: Don't fill RSB on context switch with eIBRS Josh Poimboeuf
2024-11-20 10:27 ` Shah, Amit
2024-11-20 16:21 ` jpoimboe
2024-11-21 13:28 ` Shah, Amit
2024-11-20 15:24 ` Shah, Amit
2024-11-20 18:42 ` Pawan Gupta
2024-11-21 13:29 ` [PATCH 0/2] x86/bugs: RSB tweaks Shah, Amit
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