From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Fonyuy-Asheri Caleb <fonyuy-asheri.caleb@inria.fr>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Jan Beulich <jbeulich@suse.com>
Subject: Re: Help With Identifying CPUID faulting logic in Xen code
Date: Fri, 3 Jan 2025 14:35:43 +0000 [thread overview]
Message-ID: <41b0f409-6bb3-4338-86b5-0d91dc82294e@citrix.com> (raw)
In-Reply-To: <944938302.6053932.1735914346495.JavaMail.zimbra@inria.fr>
On 03/01/2025 2:25 pm, Fonyuy-Asheri Caleb wrote:
> Hello,
>
> I am interested in finding understanding how xen handles CPUID
> faulting and
> VM exits in general. Please can someone indicate to me the concerned
> files?
>
> I want to know how xen detects the execution of the CPUID instruction and
> ensures a guest only gets the features defined in cpuid-autogen.h file
> depending on the guest type.
>
> I started looking at the file xen/arch/x86/cpuid.c but don't really
> know which other
> files to check next.
https://xenbits.xen.org/docs/unstable/features/feature-levelling.html
has a reasonable introduction. Being nearly a decade old, it's slightly
stale. AMD now have CPUID Faulting capability too, new in Zen4 CPUs IIRC.
LCAP_faulting specifically is the constant you're looking for, in the
Xen code.
~Andrew
next prev parent reply other threads:[~2025-01-03 14:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-03 14:25 Help With Identifying CPUID faulting logic in Xen code Fonyuy-Asheri Caleb
2025-01-03 14:35 ` Andrew Cooper [this message]
2025-01-03 14:54 ` Fonyuy-Asheri Caleb
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