Re: [PATCH v7 04/14] xen/arm: add Dom0 cache coloring support

From: Carlo Nonato <carlo.nonato@minervasys.tech>
To: Julien Grall <julien@xen.org>,
	Bertrand Marquis <bertrand.marquis@arm.com>,
	 Michal Orzel <michal.orzel@amd.com>,
	Volodymyr Babchuk <volodymyr_babchuk@epam.com>,
	 Stefano Stabellini <sstabellini@kernel.org>
Cc: Jan Beulich <jbeulich@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	 George Dunlap <george.dunlap@citrix.com>, Wei Liu <wl@xen.org>,
	 Marco Solieri <marco.solieri@minervasys.tech>,
	xen-devel@lists.xenproject.org,
	 Andrea Bastoni <andrea.bastoni@minervasys.tech>
Subject: Re: [PATCH v7 04/14] xen/arm: add Dom0 cache coloring support
Date: Wed, 27 Mar 2024 12:39:10 +0100	[thread overview]
Message-ID: <CAG+AhRVEM+hcEbBO5Konjty8gQtZ0kq27rPjXCqsF627t9fqwg@mail.gmail.com> (raw)
In-Reply-To: <22ab32bb-b0d0-4d68-8918-5fcb42cc0f88@suse.com>

Hi guys,

On Fri, Mar 22, 2024 at 8:26 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 21.03.2024 18:31, Carlo Nonato wrote:
> > On Thu, Mar 21, 2024 at 4:57 PM Jan Beulich <jbeulich@suse.com> wrote:
> >>
> >> On 21.03.2024 16:04, Carlo Nonato wrote:
> >>> On Tue, Mar 19, 2024 at 4:30 PM Jan Beulich <jbeulich@suse.com> wrote:
> >>>> On 15.03.2024 11:58, Carlo Nonato wrote:
> >>>>> --- a/docs/misc/xen-command-line.pandoc
> >>>>> +++ b/docs/misc/xen-command-line.pandoc
> >>>>> @@ -963,6 +963,15 @@ Controls for the dom0 IOMMU setup.
> >>>>>
> >>>>>  Specify a list of IO ports to be excluded from dom0 access.
> >>>>>
> >>>>> +### dom0-llc-colors
> >>>>> +> `= List of [ <integer> | <integer>-<integer> ]`
> >>>>> +
> >>>>> +> Default: `All available LLC colors`
> >>>>> +
> >>>>> +Specify dom0 LLC color configuration. This option is available only when
> >>>>> +`CONFIG_LLC_COLORING` is enabled. If the parameter is not set, all available
> >>>>> +colors are used.
> >>>>
> >>>> My reservation towards this being a top-level option remains.
> >>>
> >>> How can I turn this into a lower-level option? Moving it into "dom0=" doesn't
> >>> seem possible to me. How can I express a list (llc-colors) inside another list
> >>> (dom0)? dom0=llc-colors=0-3,12-15,other-param=... How can I stop parsing
> >>> before reaching other-param?
> >>
> >> For example by using a different separator:
> >>
> >> dom0=llc-colors=0-3+12-15,other-param=...
> >
> > Ok, but that would mean to change the implementation of the parsing function
> > and to adopt this syntax also in other places, something that I would've
> > preferred to avoid. Anyway I'll follow your suggestion.
>
> Well, this is all used by Arm only for now. You will want to make sure Arm
> folks are actually okay with this alternative approach.
>
> Jan

Are you Arm maintainers ok with this?

Thanks.