linux-kernel - [PATCH 4.4 25/68] Input: vmmouse

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Date:	Mon,  8 Aug 2016 21:11:00 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Sinclair Yeh <syeh@...are.com>,
	Thomas Hellstrom <thellstrom@...are.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
Subject: [PATCH 4.4 25/68] Input: vmmouse - remove port reservation

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sinclair Yeh <syeh@...are.com>

commit 60842ef8128e7bf58c024814cd0dc14319232b6c upstream.

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@...are.com>
Reviewed-by: Thomas Hellstrom <thellstrom@...are.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/input/mouse/vmmouse.c |   22 ++--------------------
 1 file changed, 2 insertions(+), 20 deletions(-)

--- a/drivers/input/mouse/vmmouse.c
+++ b/drivers/input/mouse/vmmouse.c
@@ -355,18 +355,11 @@ int vmmouse_detect(struct psmouse *psmou
 		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);
+	if (response != VMMOUSE_PROTO_MAGIC || version == 0xffffffffU)
 		return -ENXIO;
-	}
 
 	if (set_properties) {
 		psmouse->vendor = VMMOUSE_VENDOR;
@@ -374,8 +367,6 @@ int vmmouse_detect(struct psmouse *psmou
 		psmouse->model = version;
 	}
 
-	release_region(VMMOUSE_PROTO_PORT, 4);
-
 	return 0;
 }
 
@@ -394,7 +385,6 @@ static void vmmouse_disconnect(struct ps
 	psmouse_reset(psmouse);
 	input_unregister_device(priv->abs_dev);
 	kfree(priv);
-	release_region(VMMOUSE_PROTO_PORT, 4);
 }
 
 /**
@@ -438,15 +428,10 @@ 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 +487,5 @@ init_fail:
 	kfree(priv);
 	psmouse->private = NULL;
 
-release_region:
-	release_region(VMMOUSE_PROTO_PORT, 4);
-
 	return error;
 }