FAILED: patch "[PATCH] drm/vmwgfx: Map the fifo as cached" failed to apply to 4.2-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.2-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 2e586a7e017a502410ba1c1a7411179e1d3fbb2b Mon Sep 17 00:00:00 2001
From: Thomas Hellstrom <thellstrom@vmware.com>
Date: Mon, 14 Sep 2015 01:17:43 -0700
Subject: [PATCH] drm/vmwgfx: Map the fifo as cached

On the guest kernel side, previously the FIFO has been mapped write-
combined. This has worked since VMs up to now has not honored the mapping
type and mapped the FIFO cached anyway. Since the FIFO is accessed cached
by the CPU on the virtual device side, this leads to inconsistent
mappings once the guest starts to honor the mapping types.

So ask for cached mappings when we map the FIFO. We do this by
using ioremap_cache() instead of ioremap_wc(), and remove the MTRR setup.
On the TTM side, MOBs, GMRs and VRAM buffers are already requesting
cached mappings for kernel- and user-space.

Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index e13b20bd9908..2c7a25c71af2 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -752,12 +752,8 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
 	ttm_lock_set_kill(&dev_priv->fbdev_master.lock, false, SIGTERM);
 	dev_priv->active_master = &dev_priv->fbdev_master;
 
-
-	dev_priv->mmio_mtrr = arch_phys_wc_add(dev_priv->mmio_start,
-					       dev_priv->mmio_size);
-
-	dev_priv->mmio_virt = ioremap_wc(dev_priv->mmio_start,
-					 dev_priv->mmio_size);
+	dev_priv->mmio_virt = ioremap_cache(dev_priv->mmio_start,
+					    dev_priv->mmio_size);
 
 	if (unlikely(dev_priv->mmio_virt == NULL)) {
 		ret = -ENOMEM;
@@ -913,7 +909,6 @@ out_no_device:
 out_err4:
 	iounmap(dev_priv->mmio_virt);
 out_err3:
-	arch_phys_wc_del(dev_priv->mmio_mtrr);
 	vmw_ttm_global_release(dev_priv);
 out_err0:
 	for (i = vmw_res_context; i < vmw_res_max; ++i)
@@ -964,7 +959,6 @@ static int vmw_driver_unload(struct drm_device *dev)
 
 	ttm_object_device_release(&dev_priv->tdev);
 	iounmap(dev_priv->mmio_virt);
-	arch_phys_wc_del(dev_priv->mmio_mtrr);
 	if (dev_priv->ctx.staged_bindings)
 		vmw_binding_state_free(dev_priv->ctx.staged_bindings);
 	vmw_ttm_global_release(dev_priv);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index b60b41f95e74..a20f482848ee 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -376,7 +376,6 @@ struct vmw_private {
 	uint32_t initial_width;
 	uint32_t initial_height;
 	u32 __iomem *mmio_virt;
-	int mmio_mtrr;
 	uint32_t capabilities;
 	uint32_t max_gmr_ids;
 	uint32_t max_gmr_pages;