From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc: Daniel Sneddon <daniel.sneddon@linux.intel.com>,
antonio.gomez.iglesias@linux.intel.com,
alyssa.milburn@linux.intel.com, andrew.cooper3@citrix.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86/bugs: Default retbleed to =stuff when retpoline is enabled
Date: Mon, 12 Feb 2024 20:53:28 -0800 [thread overview]
Message-ID: <20240213045328.3gdcjefbdwyjv3ll@desk> (raw)
In-Reply-To: <20240212-retbleed-auto-stuff-v2-1-89401649341a@linux.intel.com>
On Mon, Feb 12, 2024 at 05:23:21PM -0800, Pawan Gupta wrote:
> On Intel systems when retpoline mitigation is enabled for spectre-v2,
> retbleed=auto does not enable RSB stuffing. This may make the system
> vulnerable to retbleed. Retpoline is not the default mitigation when
> IBRS is present, but in virtualized cases a VMM can hide IBRS from
> guests, resulting in guest deploying retpoline by default. Even if IBRS
> is enumerated, a user can still select spectre_v2=retpoline.
>
> As with other mitigations, mitigate retbleed by default. On Intel
> systems when retpoline is enabled, and retbleed mitigation is set to
> auto, enable Call Depth Tracking and RSB stuffing i.e. retbleed=stuff
> mitigation. For AMD/Hygon auto mode already selects the appropriate
> mitigation.
By mistake I sent this patch twice, please ignore the duplicate:
https://lore.kernel.org/lkml/20240213042453.6j01GG4kjjcdTev7AtniyPHPRNH3RFHNGgVJ5nIXho4@z/
prev parent reply other threads:[~2024-02-13 4:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-13 1:23 Pawan Gupta
2024-02-13 4:24 ` Pawan Gupta
2024-02-13 4:53 ` Pawan Gupta [this message]
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