From: Dave Hansen <dave.hansen@intel.com>
To: David Kaplan <david.kaplan@amd.com>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86/fpu: Disable shstk if no CET_USER state
Date: Thu, 9 Apr 2026 13:30:19 -0700 [thread overview]
Message-ID: <cc091a6e-74a1-4a86-9eb0-d3eb40deb52c@intel.com> (raw)
In-Reply-To: <20260408143044.96605-1-david.kaplan@amd.com>
On 4/8/26 07:30, David Kaplan wrote:
> + if (boot_cpu_has(X86_FEATURE_USER_SHSTK) &&
> + !(fpu_kernel_cfg.max_features & XFEATURE_MASK_CET_USER)) {
> + /*
> + * The kernel relies on XSAVES/XRSTORS to context switch shadow
> + * stack state. If this isn't present, disable user shadow
> + * stacks.
> + */
> + pr_err("x86/fpu: CET_USER not supported in xstate when CET is supported. Disabling shadow stacks.\n");
> + setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK);
> + }
Are there any more of these? I'm wondering if we want a table that's
effectively the reverse of xsave_cpuid_features[].
Maybe X86_FEATURE_ENQCMD at least?
next prev parent reply other threads:[~2026-04-09 20:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-08 14:30 David Kaplan
2026-04-09 20:30 ` Dave Hansen [this message]
2026-05-05 14:05 ` Borislav Petkov
2026-05-05 15:07 ` Borislav Petkov
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