Re: [PATCH 3/6] Input: Update vmmouse.c to use the common VMW_PORT macros

["Sinclair Yeh" <syeh@vmware.com>]

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 <syeh@vmware.com>
> > Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
> > Reviewed-by: Alok N Kataria <akataria@vmware.com>
> > Cc: pv-drivers@vmware.com
> > Cc: linux-graphics-maintainer@vmware.com
> > Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > 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 <linux/slab.h>
> >  #include <linux/module.h>
> >  #include <asm/hypervisor.h>
> > +#include <asm/vmware.h>
> >  
> >  #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.  So it's safer to initialize them to 0.  Since
they can potentially be an output, we can't make them a constant.

> 
> > +	VMW_PORT(in1, VMMOUSE_PROTO_CMD_##cmd, VMMOUSE_PROTO_PORT, \
> > +		 VMMOUSE_PROTO_MAGIC,				   \
> > +		 out1, out2, out3, out4, __dummy1, __dummy2);      \
> >  })
> >  
> 
> Thanks.
> 
> -- 
> Dmitry