From: Dave Hansen <dave.hansen@intel.com>
To: "Nikunj A. Dadhania" <nikunj@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
tglx@kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com,
hpa@zytor.com, xin@zytor.com, seanjc@google.com,
pbonzini@redhat.com, x86@kernel.org, sohil.mehta@intel.com,
jon.grimm@amd.com
Subject: Re: [PATCH v2 1/2] x86/cpu: Disable CR pinning during CPU bringup
Date: Wed, 11 Mar 2026 07:07:51 -0700 [thread overview]
Message-ID: <55a98b6d-e831-47a6-aa5a-8fe357334f67@intel.com> (raw)
In-Reply-To: <9fa61b80-0e16-4a87-a0e7-3c3dfcda8f7e@amd.com>
Nikunj, thanks for tracking this down and filling in the last piece of
the puzzle about ALTERNATIVEs patching.
On 3/11/26 03:41, Nikunj A. Dadhania wrote:
> + /*
> + * Enable FSGSBASE if available. Exception entry code (paranoid_entry)
> + * is patched to use RDGSBASE/WRGSBASE when this feature is present,
> + * and those instructions require CR4.FSGSBASE=1. Secondary CPUs must
> + * enable this before any exceptions occur.
> + */
> + if (boot_cpu_has(X86_FEATURE_FSGSBASE))
> + cr4 |= X86_CR4_FSGSBASE;
But this still double-enables X86_CR4_FSGSBASE. Could we initialize
X86_CR4_FSGSBASE in *one* place, please?
Also, please avoid passive voice in stuff like this. It's just more
efficient to say:
CPUs that support FSGSBASE may use RDGSBASE/WRGSBASE in
paranoid_entry(). Enable the feature before any exceptions
occur.
next prev parent reply other threads:[~2026-03-11 14:07 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-26 9:23 [PATCH v2 0/2] x86/fred: Fix SEV-ES/SNP guest boot failures Nikunj A Dadhania
2026-02-26 9:23 ` [PATCH v2 1/2] x86/cpu: Disable CR pinning during CPU bringup Nikunj A Dadhania
2026-03-09 13:46 ` Borislav Petkov
2026-03-09 15:38 ` Dave Hansen
2026-03-09 16:15 ` Borislav Petkov
2026-03-09 18:03 ` Dave Hansen
2026-03-09 18:40 ` Tom Lendacky
2026-03-09 19:27 ` Dave Hansen
2026-03-11 10:41 ` Nikunj A. Dadhania
2026-03-11 14:07 ` Dave Hansen [this message]
2026-03-11 15:42 ` Nikunj A. Dadhania
2026-03-11 17:28 ` Dave Hansen
2026-03-12 7:21 ` Nikunj A. Dadhania
2026-03-12 7:26 ` Nikunj A. Dadhania
2026-03-12 14:08 ` Nikunj A. Dadhania
2026-03-12 14:20 ` Dave Hansen
2026-03-12 14:53 ` Nikunj A. Dadhania
2026-03-12 15:02 ` Dave Hansen
2026-03-12 19:06 ` David Laight
2026-03-16 20:27 ` Chang S. Bae
2026-03-16 21:43 ` Dave Hansen
2026-03-17 4:12 ` Nikunj A. Dadhania
2026-03-17 14:26 ` Borislav Petkov
2026-03-17 15:31 ` Dave Hansen
2026-03-17 16:54 ` Borislav Petkov
2026-03-18 8:19 ` Nikunj A. Dadhania
2026-03-17 17:04 ` Chang S. Bae
2026-03-17 17:51 ` Chang S. Bae
2026-03-12 18:09 ` Sohil Mehta
2026-03-13 8:35 ` Nikunj A. Dadhania
2026-03-13 18:05 ` Sohil Mehta
2026-03-13 19:10 ` Borislav Petkov
2026-03-17 17:06 ` Chang S. Bae
2026-02-26 9:23 ` [PATCH v2 2/2] x86/fred: Fix early boot failures on SEV-ES/SNP guests Nikunj A Dadhania
2026-02-26 14:14 ` Tom Lendacky
2026-02-27 4:14 ` Nikunj A. Dadhania
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