Re: [PATCH v2 6/6] x86/hvm: reduce the need to flush caches in memory_type_changed()

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

On 5/19/25 4:33 PM, Roger Pau Monné wrote:
> On Mon, May 19, 2025 at 03:22:32PM +0200, Jan Beulich wrote:
> > On 19.05.2025 13:08, Roger Pau Monné wrote:
> > > On Sun, May 18, 2025 at 01:44:49PM +0200, Jan Beulich wrote:
> > > > On 16.05.2025 11:45, Roger Pau Monne wrote:
> > > > > Not sure whether this attempt to reduce cache flushing should get some
> > > > > mention in the CHANGELOG.
> > > > Err on the side of adding an entry there?
> > > Oleksii would you be fine with me adding:
> > >
> > > diff --git a/CHANGELOG.md b/CHANGELOG.md
> > > index 1ea06524db20..fa971cd9e6ee 100644
> > > --- a/CHANGELOG.md
> > > +++ b/CHANGELOG.md
> > > @@ -11,6 +11,9 @@ The format is based on [Keep a 
> > > Changelog](https://keepachangelog.com/en/1.0.0/)
> > >      - For x86, GCC 5.1 and Binutils 2.25, or Clang/LLVM 11
> > >      - For ARM32 and ARM64, GCC 5.1 and Binutils 2.25
> > >    - Linux based device model stubdomains are now fully supported.
> > > + - On x86:
> > > +   - Restrict the cache flushing done in memory_type_changed() to improve
> > > +     performance.
> > Maybe better to mention function names here, saying "after a memory type change
> > by a guest" instead?
> It's not just "after a memory type change by a guest", since
> memory_type_changed() is also used for toolstack operations like
> io{mem,ports}_{permit,deny}_access(), that strictly speaking are not
> memory type changes, neither are done by the guest itself.  I could
> reword to:
>
>     - Restrict the cache flushing done as a result of guest physical
>       memory map manipulations and memory type changes.
>
> Does that sound better?
Acked-By: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>

~ Oleksii