From: Thomas Gleixner <tglx@linutronix.de>
To: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
peterz@infradead.org, x86@kernel.org, eranian@google.com,
kan.liang@intel.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] x86/cpufeature: Add facility to match microcode revisions
Date: Sat, 20 Oct 2018 10:19:37 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1810201017070.1651@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20181019234743.GA27951@tassilo.jf.intel.com>
On Fri, 19 Oct 2018, Andi Kleen wrote:
> > > + u32 min_ucode;
> > > +};
> > > +
> > > +const struct x86_ucode_id *x86_match_ucode(const struct x86_ucode_id *match)
> >
> > What's the point of returning the struct pointer? Shouldn't it be enough to
> > make it return bool? Also the function name really should reflect that this
> > checks whether the minimal required microcode revision is active.
>
> This allows the user to find the table entry to tie something to it
> (e.g. use the index to match some other table)
>
> Same pattern as pci discovery etc. use.
>
> Given the current caller doesn't need it, but we still follow standard
> conventions.
There is no point to return the pointer because it's not a compound
structure. If you want to provide the possibility to use the index then
return the index and an error code if it does not match.
> >
> > > +{
> > > + struct cpuinfo_x86 *c = &boot_cpu_data;
> > > + const struct x86_ucode_id *m;
> > > +
> > > + for (m = match; m->vendor | m->family | m->model; m++) {
> >
> > VENDOR_INTEL = 0, so this check is obscure to begin with. Either you chose
> > a explicit condition to put at the end of the table, e.g. vendor = U8_MAX
> > or you hand in the array size to the function.
>
> That would both be awkward. It's the same as match_cpu, and 0 terminators
> are standard practice in practical all similar code. I removed
> the or with the family.
That's debatable because it's more easy to miss the terminator than getting
the ARRAY_SIZE() argument wrong. But it doesn't matter much.
Thanks,
tglx
next prev parent reply other threads:[~2018-10-20 8:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 16:26 [PATCH v2 1/2] x86/cpufeature: Add facility to match microcode revisions Andi Kleen
2018-10-10 16:26 ` [PATCH v2 2/2] perf/x86/kvm: Avoid unnecessary work in guest filtering Andi Kleen
2018-10-10 16:37 ` [PATCH v2 1/2] x86/cpufeature: Add facility to match microcode revisions Borislav Petkov
2018-10-11 11:43 ` Henrique de Moraes Holschuh
2018-10-17 9:59 ` Thomas Gleixner
2018-10-19 23:47 ` Andi Kleen
2018-10-20 8:19 ` Thomas Gleixner [this message]
2018-10-20 14:38 ` Andi Kleen
2018-10-21 10:20 ` Thomas Gleixner
2018-10-21 15:13 ` Borislav Petkov
2018-10-25 23:23 ` Andi Kleen
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=alpine.DEB.2.21.1810201017070.1651@nanos.tec.linutronix.de \
--to=tglx@linutronix.de \
--cc=ak@linux.intel.com \
--cc=andi@firstfloor.org \
--cc=eranian@google.com \
--cc=kan.liang@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--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;
as well as URLs for NNTP newsgroup(s).