From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH 3/6] Input: Update vmmouse.c to use the common VMW_PORT macros Date: Tue, 1 Dec 2015 14:45:27 -0800 Message-ID: References: <1449008047-8252-1-git-send-email-syeh@vmware.com> <1449008332-9394-1-git-send-email-syeh@vmware.com> <1449008332-9394-3-git-send-email-syeh@vmware.com> <20151201222414.GH3740@dtor-ws> <20151201223255.GA10753@syeh-linux> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20151201223255.GA10753@syeh-linux> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Sinclair Yeh Cc: Arnd Bergmann , "pv-drivers@vmware.com" , Greg Kroah-Hartman , X86 ML , lkml , virtualization@lists.linux-foundation.org, "linux-graphics-maintainer@vmware.com" , "linux-input@vger.kernel.org" List-Id: virtualization@lists.linuxfoundation.org On Tue, Dec 1, 2015 at 2:32 PM, Sinclair Yeh wrote: > Hi, > > On Tue, Dec 01, 2015 at 02:24:14PM -0800, Dmitry Torokhov wrote: >> On Tue, Dec 01, 2015 at 02:18:49PM -0800, Sinclair Yeh wrote: >> > v2: >> > Instead of replacing existing VMMOUSE defines, only modify enough >> > to use the new VMW_PORT define. >> > >> > v3: >> > Use updated VMWARE_PORT() which requires hypervisor magic as an added >> > parameter >> > >> > Signed-off-by: Sinclair Yeh >> > Reviewed-by: Thomas Hellstrom >> > Reviewed-by: Alok N Kataria >> > Cc: pv-drivers@vmware.com >> > Cc: linux-graphics-maintainer@vmware.com >> > Cc: Dmitry Torokhov >> > Cc: Arnd Bergmann >> > Cc: Greg Kroah-Hartman >> > Cc: linux-kernel@vger.kernel.org >> > Cc: virtualization@lists.linux-foundation.org >> > Cc: linux-input@vger.kernel.org >> > --- >> > drivers/input/mouse/vmmouse.c | 22 +++++++--------------- >> > 1 file changed, 7 insertions(+), 15 deletions(-) >> > >> > diff --git a/drivers/input/mouse/vmmouse.c b/drivers/input/mouse/vmmouse.c >> > index e272f06..d34e3e4 100644 >> > --- a/drivers/input/mouse/vmmouse.c >> > +++ b/drivers/input/mouse/vmmouse.c >> > @@ -19,6 +19,7 @@ >> > #include >> > #include >> > #include >> > +#include >> > >> > #include "psmouse.h" >> > #include "vmmouse.h" >> > @@ -84,21 +85,12 @@ struct vmmouse_data { >> > * implementing the vmmouse protocol. Should never execute on >> > * bare metal hardware. >> > */ >> > -#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? Thanks. -- Dmitry