[PATCH] Input: vmmouse - remove port reservation

[PATCH] Input: vmmouse - remove port reservation

[Sinclair Yeh]

The VMWare EFI BIOS will expose port 0x5658 as an ACPI resource.  This
causes the port to be reserved by the APCI module as the system comes up,
making it unavailable to be reserved again by other drivers, thus
preserving this VMWare port for special use in a VMWare guest.

This port is designed to be shared among multiple VMWare services, such as
the VMMOUSE.  Because of this, VMMOUSE should not try to reserve this port
on its own.

The VMWare non-EFI BIOS does not do this to preserve compatibility with
existing/legacy VMs.  It is known that there is small chance a VM may be
configured such that these ports get reserved by other non-VMWare devices,
and if this ever happens, the result is undefined.

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: <stable@vger.kernel.org> # 4.1-
Cc: linux-input@vger.kernel.org
Cc: pv-drivers@vmware.com
---
My previous attempt at sending this might have failed.
Resending...
---
 drivers/input/mouse/vmmouse.c | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/drivers/input/mouse/vmmouse.c b/drivers/input/mouse/vmmouse.c
index a3f0f5a..8f2c408 100644
--- a/drivers/input/mouse/vmmouse.c
+++ b/drivers/input/mouse/vmmouse.c
@@ -355,16 +355,10 @@ int vmmouse_detect(struct psmouse *psmouse, bool set_properties)
 		return -ENXIO;
 	}
 
-	if (!request_region(VMMOUSE_PROTO_PORT, 4, "vmmouse")) {
-		psmouse_dbg(psmouse, "VMMouse port in use.\n");
-		return -EBUSY;
-	}
-
 	/* Check if the device is present */
 	response = ~VMMOUSE_PROTO_MAGIC;
 	VMMOUSE_CMD(GETVERSION, 0, version, response, dummy1, dummy2);
 	if (response != VMMOUSE_PROTO_MAGIC || version == 0xffffffffU) {
-		release_region(VMMOUSE_PROTO_PORT, 4);
 		return -ENXIO;
 	}
 
@@ -374,8 +368,6 @@ int vmmouse_detect(struct psmouse *psmouse, bool set_properties)
 		psmouse->model = version;
 	}
 
-	release_region(VMMOUSE_PROTO_PORT, 4);
-
 	return 0;
 }
 
@@ -394,7 +386,6 @@ static void vmmouse_disconnect(struct psmouse *psmouse)
 	psmouse_reset(psmouse);
 	input_unregister_device(priv->abs_dev);
 	kfree(priv);
-	release_region(VMMOUSE_PROTO_PORT, 4);
 }
 
 /**
@@ -438,15 +429,10 @@ int vmmouse_init(struct psmouse *psmouse)
 	struct input_dev *rel_dev = psmouse->dev, *abs_dev;
 	int error;
 
-	if (!request_region(VMMOUSE_PROTO_PORT, 4, "vmmouse")) {
-		psmouse_dbg(psmouse, "VMMouse port in use.\n");
-		return -EBUSY;
-	}
-
 	psmouse_reset(psmouse);
 	error = vmmouse_enable(psmouse);
 	if (error)
-		goto release_region;
+		return error;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	abs_dev = input_allocate_device();
@@ -502,8 +488,5 @@ init_fail:
 	kfree(priv);
 	psmouse->private = NULL;
 
-release_region:
-	release_region(VMMOUSE_PROTO_PORT, 4);
-
 	return error;
 }
-- 
2.7.4

Re: [PATCH] Input: vmmouse - remove port reservation

[Dmitry Torokhov]

On Tue, May 31, 2016 at 10:25:58AM -0700, Sinclair Yeh wrote:
> The VMWare EFI BIOS will expose port 0x5658 as an ACPI resource.  This
> causes the port to be reserved by the APCI module as the system comes up,
> making it unavailable to be reserved again by other drivers, thus
> preserving this VMWare port for special use in a VMWare guest.
> 
> This port is designed to be shared among multiple VMWare services, such as
> the VMMOUSE.  Because of this, VMMOUSE should not try to reserve this port
> on its own.
> 
> The VMWare non-EFI BIOS does not do this to preserve compatibility with
> existing/legacy VMs.  It is known that there is small chance a VM may be
> configured such that these ports get reserved by other non-VMWare devices,
> and if this ever happens, the result is undefined.
> 
> Signed-off-by: Sinclair Yeh <syeh@vmware.com>
> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
> Cc: <stable@vger.kernel.org> # 4.1-
> Cc: linux-input@vger.kernel.org
> Cc: pv-drivers@vmware.com

Applied, thank you.

> ---
> My previous attempt at sending this might have failed.
> Resending...
> ---
>  drivers/input/mouse/vmmouse.c | 19 +------------------
>  1 file changed, 1 insertion(+), 18 deletions(-)
> 
> diff --git a/drivers/input/mouse/vmmouse.c b/drivers/input/mouse/vmmouse.c
> index a3f0f5a..8f2c408 100644
> --- a/drivers/input/mouse/vmmouse.c
> +++ b/drivers/input/mouse/vmmouse.c
> @@ -355,16 +355,10 @@ int vmmouse_detect(struct psmouse *psmouse, bool set_properties)
>  		return -ENXIO;
>  	}
>  
> -	if (!request_region(VMMOUSE_PROTO_PORT, 4, "vmmouse")) {
> -		psmouse_dbg(psmouse, "VMMouse port in use.\n");
> -		return -EBUSY;
> -	}
> -
>  	/* Check if the device is present */
>  	response = ~VMMOUSE_PROTO_MAGIC;
>  	VMMOUSE_CMD(GETVERSION, 0, version, response, dummy1, dummy2);
>  	if (response != VMMOUSE_PROTO_MAGIC || version == 0xffffffffU) {
> -		release_region(VMMOUSE_PROTO_PORT, 4);
>  		return -ENXIO;
>  	}
>  
> @@ -374,8 +368,6 @@ int vmmouse_detect(struct psmouse *psmouse, bool set_properties)
>  		psmouse->model = version;
>  	}
>  
> -	release_region(VMMOUSE_PROTO_PORT, 4);
> -
>  	return 0;
>  }
>  
> @@ -394,7 +386,6 @@ static void vmmouse_disconnect(struct psmouse *psmouse)
>  	psmouse_reset(psmouse);
>  	input_unregister_device(priv->abs_dev);
>  	kfree(priv);
> -	release_region(VMMOUSE_PROTO_PORT, 4);
>  }
>  
>  /**
> @@ -438,15 +429,10 @@ int vmmouse_init(struct psmouse *psmouse)
>  	struct input_dev *rel_dev = psmouse->dev, *abs_dev;
>  	int error;
>  
> -	if (!request_region(VMMOUSE_PROTO_PORT, 4, "vmmouse")) {
> -		psmouse_dbg(psmouse, "VMMouse port in use.\n");
> -		return -EBUSY;
> -	}
> -
>  	psmouse_reset(psmouse);
>  	error = vmmouse_enable(psmouse);
>  	if (error)
> -		goto release_region;
> +		return error;
>  
>  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>  	abs_dev = input_allocate_device();
> @@ -502,8 +488,5 @@ init_fail:
>  	kfree(priv);
>  	psmouse->private = NULL;
>  
> -release_region:
> -	release_region(VMMOUSE_PROTO_PORT, 4);
> -
>  	return error;
>  }
> -- 
> 2.7.4
> 

-- 
Dmitry