Re: [PATCH v1 26/28] docs: add coverage for svm_avic=

[dmukhin@ford.com]

On Thu, Nov 05, 2026 at 09:24:09AM +0100, Jan Beulich wrote:
> On 05.11.2026 02:33, dmukhin@ford.com wrote:
> > @@ -2673,6 +2673,27 @@ On Sappire and Emerald Rapids CPUs with May 2025 microcode or later, the
> >  `ibpb-alt=` option can be used to switch to the alternative mitigation for
> >  Intel SA-00982.  Intel suggest that some workloads will benefit from this.
> >  
> > +### svm_avic (x86)
> > +> `= true | false | nodoorbell`
> > +
> > +This option configures Advanced Virtual Interrupt Controller (AVIC), which
> > +is an extension of AMD Secure Virtual Machine (SVM) to virtualize local APIC
> > +for guest VM.
> > +
> > +This parameter is experimental and for expert configuration only.
> > +
> > +Xen has mitigatations for the following AVIC hardware flaws:
> 
> Nit: mitigations
> 
> > + * AMD Erratum 1235. A hardware flaw affecting certain AMD Family 17h and
> > +   Hygon Family 18h processors where the CPU hardware reads a stale
> > +   `IsRunning=1` bit during Interrupt Control Register (ICR) write emulation.
> > +
> > +Limitations:
> > +
> > + * AVIC in x2APIC mode is not supported.
> > +
> > + * AVIC in nested virtualization setup is not supported.
> > +
> >  ### sync_console
> >  > `= <boolean>`
> 
> This wants to be part of the patch where the option is introduced. New options

I introduced 'svm_avic=nodoorbell' later in the series, after 
svm_avic= appears for the first time. So my thinking was to document
all new options in one patch...

> also want to use dashes in favor of underscores. Plus the default setting of
> this option wants making explicit.

Will switch to dashes.

> 
> Jan
>