drm/vmwgfx: Use the common gem mmap instead of the custom code

jira VULN-8161
cve CVE-2023-5633
commit-author Zack Rusin <zackr@vmware.com>
commit 9da2957

Before vmwgfx supported gem it needed to implement the entire mmap logic
explicitly. With GEM support that's not needed and the generic code
can be used by simply setting the vm_ops to vmwgfx specific ones on the
gem object itself.

Removes a lot of code from vmwgfx without any functional difference.

	Signed-off-by: Zack Rusin <zackr@vmware.com>
	Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
	Reviewed-by: Martin Krastev <krastevm@vmware.com>
	Reviewed-by: Maaz Mombasawala <mombasawalam@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230131033542.953249-2-zack@kde.org
(cherry picked from commit 9da2957)
	Signed-off-by: Sultan Alsawaf <sultan@ciq.com>

Author: kerneltoast

drivers/gpu/drm/vmwgfx/Makefile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 vmwgfx-y := vmwgfx_execbuf.o vmwgfx_gmr.o vmwgfx_kms.o vmwgfx_drv.o \
 	    vmwgfx_ioctl.o vmwgfx_resource.o vmwgfx_ttm_buffer.o \
-	    vmwgfx_cmd.o vmwgfx_irq.o vmwgfx_ldu.o vmwgfx_ttm_glue.o \
+	    vmwgfx_cmd.o vmwgfx_irq.o vmwgfx_ldu.o \
 	    vmwgfx_overlay.o vmwgfx_gmrid_manager.o vmwgfx_fence.o \
 	    vmwgfx_bo.o vmwgfx_scrn.o vmwgfx_context.o \
 	    vmwgfx_surface.o vmwgfx_prime.o vmwgfx_mob.o vmwgfx_shader.o \

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -1578,7 +1578,7 @@ static const struct file_operations vmwgfx_driver_fops = {
 	.open = drm_open,
 	.release = drm_release,
 	.unlocked_ioctl = vmw_unlocked_ioctl,
-	.mmap = vmw_mmap,
+	.mmap = drm_gem_mmap,
 	.poll = drm_poll,
 	.read = drm_read,
 #if defined(CONFIG_COMPAT)

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

@@ -1053,12 +1053,6 @@ vmw_is_cursor_bypass3_enabled(const struct vmw_private *dev_priv)
 	return (vmw_fifo_caps(dev_priv) & SVGA_FIFO_CAP_CURSOR_BYPASS_3) != 0;
 }
 
-/**
- * TTM glue - vmwgfx_ttm_glue.c
- */
-
-extern int vmw_mmap(struct file *filp, struct vm_area_struct *vma);
-
 /**
  * TTM buffer object driver - vmwgfx_ttm_buffer.c
  */

drivers/gpu/drm/vmwgfx/vmwgfx_gem.c

@@ -103,6 +103,13 @@ static struct sg_table *vmw_gem_object_get_sg_table(struct drm_gem_object *obj)
 	return drm_prime_pages_to_sg(obj->dev, vmw_tt->dma_ttm.pages, vmw_tt->dma_ttm.num_pages);
 }
 
+static const struct vm_operations_struct vmw_vm_ops = {
+	.pfn_mkwrite = vmw_bo_vm_mkwrite,
+	.page_mkwrite = vmw_bo_vm_mkwrite,
+	.fault = vmw_bo_vm_fault,
+	.open = ttm_bo_vm_open,
+	.close = ttm_bo_vm_close,
+};
 
 static const struct drm_gem_object_funcs vmw_gem_object_funcs = {
 	.free = vmw_gem_object_free,
@@ -115,6 +122,7 @@ static const struct drm_gem_object_funcs vmw_gem_object_funcs = {
 	.vmap = drm_gem_ttm_vmap,
 	.vunmap = drm_gem_ttm_vunmap,
 	.mmap = drm_gem_ttm_mmap,
+	.vm_ops = &vmw_vm_ops,
 };
 
 /**