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
next prev parent reply other threads:[~2021-04-12 22:25 UTC|newest]
Thread overview: 13+ 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 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]
2021-04-14 4:02 ` Leonardo Bras
2021-04-08 7:48 ` kernel test robot
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