From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Dave Hansen <dave.hansen@intel.com>,
"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: Mon, 16 Mar 2026 13:27:18 -0700 [thread overview]
Message-ID: <c13736a1-3151-476b-a91c-035383d2a29e@intel.com> (raw)
In-Reply-To: <ab5bf7bb-6511-49dc-a65d-86911e0f7091@intel.com>
On 3/12/2026 7:20 AM, Dave Hansen wrote:
> On 3/12/26 07:08, Nikunj A. Dadhania wrote:
>> 1) Back-porting complexity: The current issue affects kernels (6.9+)
>> where SEV-SNP guests fail to boot with FRED enabled. A simpler fix would
>> be easier to backport and verify across stable branches.
>
> The simplest fix is to disable FRED on those kernels, fwiw.
In addition to this,
On SEV systems, early exceptions appear to be expected in practice while
CR4.FSGSBASE=0. So, at the moment, it also looks safe and simple to
disable the feature until when those entry paths are adjusted to
tolerate that case.
Currently, those entry paths are patched to use FSGSBASE instructions
regardless of the CR4 setting. That inflexibility appears to make it
broken in the first place. I’d take a look and come back with something
reviewable.
next prev parent reply other threads:[~2026-03-16 20:27 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
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 [this message]
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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