From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Sinclair Yeh <syeh@vmware.com>
Cc: X86 ML <x86@kernel.org>,
"pv-drivers@vmware.com" <pv-drivers@vmware.com>,
"linux-graphics-maintainer@vmware.com"
<linux-graphics-maintainer@vmware.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
lkml <linux-kernel@vger.kernel.org>,
virtualization@lists.linux-foundation.org,
"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>
Subject: Re: [PATCH 3/6] Input: Update vmmouse.c to use the common VMW_PORT macros
Date: Tue, 1 Dec 2015 15:56:39 -0800 [thread overview]
Message-ID: <CAKdAkRThOqXpVPYbSTE305_6=sOK8Kfbxfof_ybvJxvm4ge9Kg@mail.gmail.com> (raw)
In-Reply-To: <20151201225420.GA11210@syeh-linux>
On Tue, Dec 1, 2015 at 2:54 PM, Sinclair Yeh <syeh@vmware.com> wrote:
> Hi,
>
> On Tue, Dec 01, 2015 at 02:45:27PM -0800, Dmitry Torokhov wrote:
>> On Tue, Dec 1, 2015 at 2:32 PM, Sinclair Yeh <syeh@vmware.com> wrote:
>> > Hi,
>> >
>
> <snip>
>
>> >> > */
>> >> > -#define VMMOUSE_CMD(cmd, in1, out1, out2, out3, out4) \
>> >> > -({ \
>> >> > - unsigned long __dummy1, __dummy2; \
>> >> > - __asm__ __volatile__ ("inl %%dx" : \
>> >> > - "=a"(out1), \
>> >> > - "=b"(out2), \
>> >> > - "=c"(out3), \
>> >> > - "=d"(out4), \
>> >> > - "=S"(__dummy1), \
>> >> > - "=D"(__dummy2) : \
>> >> > - "a"(VMMOUSE_PROTO_MAGIC), \
>> >> > - "b"(in1), \
>> >> > - "c"(VMMOUSE_PROTO_CMD_##cmd), \
>> >> > - "d"(VMMOUSE_PROTO_PORT) : \
>> >> > - "memory"); \
>> >> > +#define VMMOUSE_CMD(cmd, in1, out1, out2, out3, out4) \
>> >> > +({ \
>> >> > + unsigned long __dummy1 = 0, __dummy2 = 0; \
>> >>
>> >> Why do we need to initialize dummies?
>> >
>> > Because for some commands those parameters to VMW_PORT() can be both
>> > input and outout.
>>
>> The vmmouse commands do not use them as input though, so it seems we
>> are simply wasting CPU cycles setting them to 0 just because we are
>> using the new VMW_PORT here. Why do we need to switch? What is the
>> benefit of doing this?
>
> There are two reasons. One is to make the code more readable and
> maintainable. Rather than having mostly similar inline assembly
> code sprinkled across multiple modules, we can just use the macros
> and document that.
At the cost of wasting cycles though :(.
Oh well, it is not like we are polling the backdoor here, so if you do
not care about a few wasted cycles I don't have to either ;)
>
> The second reason is this organization makes some on-going future
> development easier.
>
> Hope this helps.
>
> Sinclair
--
Dmitry
next prev parent reply other threads:[~2015-12-01 23:56 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1449008047-8252-1-git-send-email-syeh@vmware.com>
2015-12-01 22:18 ` [PATCH 1/6] x86: Add VMWare Host Communication Macros Sinclair Yeh
2015-12-01 22:18 ` Sinclair Yeh
2015-12-01 22:18 ` [PATCH 2/6] x86: Update vmware.c to use the common VMW_PORT macros Sinclair Yeh
2015-12-01 22:18 ` Sinclair Yeh
2015-12-01 22:18 ` [PATCH 3/6] Input: Update vmmouse.c " Sinclair Yeh
2015-12-01 22:18 ` Sinclair Yeh
2015-12-01 22:24 ` Dmitry Torokhov
2015-12-01 22:32 ` Sinclair Yeh
2015-12-01 22:45 ` Dmitry Torokhov
2015-12-01 22:45 ` Dmitry Torokhov
2015-12-01 22:45 ` Dmitry Torokhov
2015-12-01 22:54 ` Sinclair Yeh
2015-12-01 22:54 ` Sinclair Yeh
2015-12-01 23:56 ` Dmitry Torokhov
2015-12-01 23:56 ` Dmitry Torokhov [this message]
2015-12-01 23:56 ` Dmitry Torokhov
2015-12-02 0:04 ` Greg Kroah-Hartman
2015-12-02 0:04 ` Greg Kroah-Hartman
2015-12-02 2:21 ` Sinclair Yeh
2015-12-02 2:21 ` Sinclair Yeh
2015-12-02 15:31 ` Greg Kroah-Hartman
2015-12-02 15:31 ` Greg Kroah-Hartman
2015-12-02 15:57 ` Sinclair Yeh
2015-12-02 15:57 ` Sinclair Yeh
2015-12-02 15:57 ` Sinclair Yeh
2015-12-02 17:26 ` Dmitry Torokhov
2015-12-02 17:26 ` Dmitry Torokhov
2015-12-02 17:29 ` [Linux-graphics-maintainer] " Thomas Hellstrom
2015-12-02 17:29 ` Thomas Hellstrom
2015-12-02 18:45 ` Greg Kroah-Hartman
2015-12-02 18:45 ` Greg Kroah-Hartman
2015-12-02 18:58 ` Dmitry Torokhov
2015-12-02 18:58 ` Dmitry Torokhov
2015-12-02 18:58 ` Dmitry Torokhov
2015-12-02 19:02 ` Sinclair Yeh
2015-12-02 19:02 ` Sinclair Yeh
2015-12-02 2:21 ` Sinclair Yeh
2015-12-02 7:07 ` [Linux-graphics-maintainer] " Thomas Hellstrom
2015-12-02 7:07 ` Thomas Hellstrom
2015-12-02 7:07 ` Thomas Hellstrom
2015-12-01 22:32 ` Sinclair Yeh
2015-12-01 22:24 ` Dmitry Torokhov
2015-12-02 0:01 ` Greg Kroah-Hartman
2015-12-02 0:01 ` Greg Kroah-Hartman
2015-12-01 22:18 ` [PATCH 4/6] Input: Remove vmmouse port reservation Sinclair Yeh
2015-12-01 22:30 ` Dmitry Torokhov
2015-12-01 22:30 ` Dmitry Torokhov
2015-12-01 23:04 ` Sinclair Yeh
2015-12-01 23:04 ` Sinclair Yeh
2015-12-01 23:52 ` Dmitry Torokhov
2015-12-01 23:52 ` Dmitry Torokhov
2015-12-01 22:18 ` Sinclair Yeh
2015-12-01 22:18 ` [PATCH 5/6] x86: Remove address from the vmware.c header Sinclair Yeh
2015-12-01 22:18 ` [PATCH 6/6] VMware balloon: Update vmw_balloon.c to use the VMW_PORT macro Sinclair Yeh
2015-12-01 22:38 ` Xavier Deguillard
2015-12-01 23:17 ` Sinclair Yeh
2015-12-01 23:17 ` Sinclair Yeh
2015-12-01 22:38 ` Xavier Deguillard
2015-12-01 22:18 ` Sinclair Yeh
2015-12-01 22:32 ` [PATCH 1/6] x86: Add VMWare Host Communication Macros Xavier Deguillard
2015-12-01 22:32 ` Xavier Deguillard
2015-12-01 22:49 ` H. Peter Anvin
2015-12-04 22:33 ` Sinclair Yeh
2015-12-04 22:33 ` Sinclair Yeh
2015-12-01 22:49 ` H. Peter Anvin
[not found] ` <1449271183-1746-1-git-send-email-syeh@vmware.com>
2015-12-04 23:19 ` Sinclair Yeh
2015-12-04 23:19 ` Sinclair Yeh
2015-12-04 23:19 ` [PATCH 2/6] x86: Update vmware.c to use the common VMW_PORT macros Sinclair Yeh
2015-12-04 23:19 ` Sinclair Yeh
2015-12-04 23:19 ` [PATCH 3/6] Input: Update vmmouse.c " Sinclair Yeh
2015-12-04 23:19 ` Sinclair Yeh
2015-12-04 23:19 ` [PATCH 4/6] Input: Remove vmmouse port reservation Sinclair Yeh
2015-12-04 23:19 ` Sinclair Yeh
2015-12-04 23:19 ` [PATCH 5/6] x86: Remove address from the vmware.c header Sinclair Yeh
2015-12-04 23:19 ` [PATCH 6/6] VMware balloon: Update vmw_balloon.c to use the VMW_PORT macro Sinclair Yeh
2015-12-04 23:19 ` Sinclair Yeh
2016-01-19 21:45 ` [PATCH 0/6] Create common VMWare host port communication macros v3 Sinclair Yeh
2016-01-19 21:46 ` [PATCH 1/6] x86: Add VMWare Host Communication Macros Sinclair Yeh
2016-01-19 21:46 ` Sinclair Yeh
2016-01-19 21:46 ` [PATCH 2/6] x86: Update vmware.c to use the common VMW_PORT macros Sinclair Yeh
2016-01-19 21:46 ` Sinclair Yeh
2016-01-19 21:46 ` [PATCH 3/6] Input: Update vmmouse.c " Sinclair Yeh
2016-01-19 21:46 ` Sinclair Yeh
2016-01-19 21:46 ` [PATCH 4/6] Input: Remove vmmouse port reservation Sinclair Yeh
2016-01-19 21:46 ` Sinclair Yeh
2016-01-19 21:46 ` [PATCH 5/6] x86: Remove address from the vmware.c header Sinclair Yeh
2016-01-19 21:46 ` [PATCH 6/6] VMware balloon: Update vmw_balloon.c to use the VMW_PORT macro Sinclair Yeh
2016-01-19 21:46 ` Sinclair Yeh
2016-02-08 19:41 ` Greg KH
2016-02-08 19:41 ` Greg KH
2016-03-31 14:39 ` Sinclair Yeh
2016-03-31 14:39 ` Sinclair Yeh
2016-03-31 16:30 ` Greg KH
2016-03-31 16:30 ` Greg KH
2016-03-31 17:32 ` Sinclair Yeh
2016-03-31 17:32 ` Sinclair Yeh
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