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Commit 95cf9264 authored by Tom Lendacky's avatar Tom Lendacky Committed by Ingo Molnar
Browse files

x86, drm, fbdev: Do not specify encrypted memory for video mappings 



Since video memory needs to be accessed decrypted, be sure that the
memory encryption mask is not set for the video ranges.

Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/a19436f30424402e01f63a09b32ab103272acced.1500319216.git.thomas.lendacky@amd.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 46d010e0

arch/x86/include/asm/vga.h

+13 −1
Original line number Diff line number Diff line
@@ -7,12 +7,24 @@ 
#ifndef _ASM_X86_VGA_H

#define _ASM_X86_VGA_H



#include <asm/set_memory.h>



/*

 *	On the PC, we can just recalculate addresses and then

 *	access the videoram directly without any black magic.

 *	To support memory encryption however, we need to access

 *	the videoram as decrypted memory.

 */



#define VGA_MAP_MEM(x, s) (unsigned long)phys_to_virt(x)

#define VGA_MAP_MEM(x, s)					\

({								\

	unsigned long start = (unsigned long)phys_to_virt(x);	\

								\

	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT))			\

		set_memory_decrypted(start, (s) >> PAGE_SHIFT);	\

								\

	start;							\

})



#define vga_readb(x) (*(x))

#define vga_writeb(x, y) (*(y) = (x))

arch/x86/mm/pageattr.c

+2 −0
Original line number Diff line number Diff line
@@ -1831,11 +1831,13 @@ int set_memory_encrypted(unsigned long addr, int numpages) 
{

	return __set_memory_enc_dec(addr, numpages, true);

}

EXPORT_SYMBOL_GPL(set_memory_encrypted);



int set_memory_decrypted(unsigned long addr, int numpages)

{

	return __set_memory_enc_dec(addr, numpages, false);

}

EXPORT_SYMBOL_GPL(set_memory_decrypted);



int set_pages_uc(struct page *page, int numpages)

{

drivers/gpu/drm/drm_gem.c

+2 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include <linux/pagemap.h>

#include <linux/shmem_fs.h>

#include <linux/dma-buf.h>

#include <linux/mem_encrypt.h>

#include <drm/drmP.h>

#include <drm/drm_vma_manager.h>

#include <drm/drm_gem.h>
@@ -928,6 +929,7 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size, 
	vma->vm_ops = dev->driver->gem_vm_ops;

	vma->vm_private_data = obj;

	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));

	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);



	/* Take a ref for this mapping of the object, so that the fault

	 * handler can dereference the mmap offset's pointer to the object.

drivers/gpu/drm/drm_vm.c

+4 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ 
#include <linux/efi.h>

#include <linux/slab.h>

#endif

#include <linux/mem_encrypt.h>

#include <asm/pgtable.h>

#include "drm_internal.h"

#include "drm_legacy.h"
@@ -58,6 +59,9 @@ static pgprot_t drm_io_prot(struct drm_local_map *map, 
{

	pgprot_t tmp = vm_get_page_prot(vma->vm_flags);



	/* We don't want graphics memory to be mapped encrypted */

	tmp = pgprot_decrypted(tmp);



#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)

	if (map->type == _DRM_REGISTERS && !(map->flags & _DRM_WRITE_COMBINING))

		tmp = pgprot_noncached(tmp);

drivers/gpu/drm/ttm/ttm_bo_vm.c

+5 −2
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include <linux/rbtree.h>

#include <linux/module.h>

#include <linux/uaccess.h>

#include <linux/mem_encrypt.h>



#define TTM_BO_VM_NUM_PREFAULT 16
@@ -230,9 +231,11 @@ static int ttm_bo_vm_fault(struct vm_fault *vmf) 
	 * first page.

	 */

	for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {

		if (bo->mem.bus.is_iomem)

		if (bo->mem.bus.is_iomem) {

			/* Iomem should not be marked encrypted */

			cvma.vm_page_prot = pgprot_decrypted(cvma.vm_page_prot);

			pfn = bdev->driver->io_mem_pfn(bo, page_offset);

		else {

		} else {

			page = ttm->pages[page_offset];

			if (unlikely(!page && i == 0)) {

				retval = VM_FAULT_OOM;