From: Segher Boessenkool <segher@kernel.crashing.org>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Leonardo Bras <leobras.c@gmail.com>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
brking@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 1/1] powerpc/iommu: Enable remaining IOMMU Pagesizes present in LoPAR
Date: Mon, 12 Apr 2021 17:21:43 -0500 [thread overview]
Message-ID: <20210412222143.GO26583@gate.crashing.org> (raw)
In-Reply-To: <21407a96-5b20-3fae-f1c8-895973b655ef@ozlabs.ru>
On Fri, Apr 09, 2021 at 02:36:16PM +1000, Alexey Kardashevskiy wrote:
> On 08/04/2021 19:04, Michael Ellerman wrote:
> >>>>+#define QUERY_DDW_PGSIZE_4K 0x01
> >>>>+#define QUERY_DDW_PGSIZE_64K 0x02
> >>>>+#define QUERY_DDW_PGSIZE_16M 0x04
> >>>>+#define QUERY_DDW_PGSIZE_32M 0x08
> >>>>+#define QUERY_DDW_PGSIZE_64M 0x10
> >>>>+#define QUERY_DDW_PGSIZE_128M 0x20
> >>>>+#define QUERY_DDW_PGSIZE_256M 0x40
> >>>>+#define QUERY_DDW_PGSIZE_16G 0x80
> >>>
> >>>I'm not sure the #defines really gain us much vs just putting the
> >>>literal values in the array below?
> >>
> >>Then someone says "uuuuu magic values" :) I do not mind either way.
> >>Thanks,
> >
> >Yeah that's true. But #defining them doesn't make them less magic, if
> >you only use them in one place :)
>
> Defining them with "QUERY_DDW" in the names kinda tells where they are
> from. Can also grep QEMU using these to see how the other side handles
> it. Dunno.
And *not* defining anything reduces the mental load a lot. You can add
a comment at the single spot you use them, explaining what this is, in a
much better way!
Comments are *good*.
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Leonardo Bras <leobras.c@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
brking@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/1] powerpc/iommu: Enable remaining IOMMU Pagesizes present in LoPAR
Date: Mon, 12 Apr 2021 17:21:43 -0500 [thread overview]
Message-ID: <20210412222143.GO26583@gate.crashing.org> (raw)
In-Reply-To: <21407a96-5b20-3fae-f1c8-895973b655ef@ozlabs.ru>
On Fri, Apr 09, 2021 at 02:36:16PM +1000, Alexey Kardashevskiy wrote:
> On 08/04/2021 19:04, Michael Ellerman wrote:
> >>>>+#define QUERY_DDW_PGSIZE_4K 0x01
> >>>>+#define QUERY_DDW_PGSIZE_64K 0x02
> >>>>+#define QUERY_DDW_PGSIZE_16M 0x04
> >>>>+#define QUERY_DDW_PGSIZE_32M 0x08
> >>>>+#define QUERY_DDW_PGSIZE_64M 0x10
> >>>>+#define QUERY_DDW_PGSIZE_128M 0x20
> >>>>+#define QUERY_DDW_PGSIZE_256M 0x40
> >>>>+#define QUERY_DDW_PGSIZE_16G 0x80
> >>>
> >>>I'm not sure the #defines really gain us much vs just putting the
> >>>literal values in the array below?
> >>
> >>Then someone says "uuuuu magic values" :) I do not mind either way.
> >>Thanks,
> >
> >Yeah that's true. But #defining them doesn't make them less magic, if
> >you only use them in one place :)
>
> Defining them with "QUERY_DDW" in the names kinda tells where they are
> from. Can also grep QEMU using these to see how the other side handles
> it. Dunno.
And *not* defining anything reduces the mental load a lot. You can add
a comment at the single spot you use them, explaining what this is, in a
much better way!
Comments are *good*.
Segher
next prev parent reply other threads:[~2021-04-12 22:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 19:56 [PATCH v2 1/1] powerpc/iommu: Enable remaining IOMMU Pagesizes present in LoPAR Leonardo Bras
2021-04-08 0:22 ` kernel test robot
2021-04-08 0:22 ` kernel test robot
2021-04-08 0:22 ` kernel test robot
2021-04-08 5:37 ` Michael Ellerman
2021-04-08 6:20 ` Leonardo Bras
2021-04-08 6:35 ` Leonardo Bras
2021-04-08 9:08 ` Michael Ellerman
2021-04-08 7:13 ` Alexey Kardashevskiy
2021-04-08 9:04 ` Michael Ellerman
2021-04-09 4:36 ` Alexey Kardashevskiy
2021-04-09 4:44 ` Leonardo Bras
2021-04-12 22:21 ` Segher Boessenkool [this message]
2021-04-12 22:21 ` Segher Boessenkool
2021-04-14 4:02 ` Leonardo Bras
2021-04-14 4:02 ` Leonardo Bras
2021-04-08 7:48 ` kernel test robot
2021-04-08 7:48 ` kernel test robot
2021-04-08 7:48 ` kernel test robot
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=20210412222143.GO26583@gate.crashing.org \
--to=segher@kernel.crashing.org \
--cc=aik@ozlabs.ru \
--cc=brking@linux.vnet.ibm.com \
--cc=leobras.c@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=paulus@samba.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.