From: Dave Hansen <dave.hansen@intel.com>
To: Tom Lendacky <thomas.lendacky@amd.com>,
linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Asish Kalra <ashish.kalra@amd.com>,
Michael Roth <michael.roth@amd.com>,
Joerg Roedel <jroedel@suse.de>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
stable@vger.kernel.org, Sean Christopherson <seanjc@google.com>
Subject: Re: [PATCH] x86/sev: Don't use cc_platform_has() for early SEV-SNP calls
Date: Wed, 24 Aug 2022 11:43:10 -0700 [thread overview]
Message-ID: <10bc452f-3564-e41b-836d-e135a8f4260d@intel.com> (raw)
In-Reply-To: <0c9b9a6c33ff4b8ce17a87a6c09db44d3b52bad3.1661291751.git.thomas.lendacky@amd.com>
On 8/23/22 14:55, Tom Lendacky wrote:
> When running identity mapped and depending on the kernel configuration,
> it is possible that cc_platform_has() can have compiler generated code
> that uses jump tables. This causes a boot failure because the jump table
> uses un-mapped kernel virtual addresses, not identity mapped addresses.
> This has been seen with CONFIG_RETPOLINE=n.
So, we don't have *ANY* control over where the compiler uses jump
tables. The kernel just happened to add some code that uses them, fell
over, and this adds a hack to get booting again.
Isn't this a bigger problem?
next prev parent reply other threads:[~2022-08-24 18:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 21:55 Tom Lendacky
2022-08-24 18:43 ` Dave Hansen [this message]
2022-08-24 18:48 ` Borislav Petkov
2022-08-24 18:53 ` Dave Hansen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=10bc452f-3564-e41b-836d-e135a8f4260d@intel.com \
--to=dave.hansen@intel.com \
--cc=ashish.kalra@amd.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=hpa@zytor.com \
--cc=jroedel@suse.de \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=michael.roth@amd.com \
--cc=mingo@redhat.com \
--cc=seanjc@google.com \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®