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x86, swiotlb: Add memory encryption support

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Since DMA addresses will effectively look like 48-bit addresses when the
memory encryption mask is set, SWIOTLB is needed if the DMA mask of the
device performing the DMA does not support 48-bits. SWIOTLB will be
initialized to create decrypted bounce buffers for use by these devices.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.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/aa2d29b78ae7d508db8881e46a3215231b9327a7.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Tom Lendacky 2017-07-17 16:10:21 -05:00 committed by Ingo Molnar
parent 163ea3c83a
commit c7753208a9
9 changed files with 108 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/x86/include/asm/dma-mapping.h
View File

@ -12,6 +12,7 @@
#include <asm/io.h>
#include <asm/swiotlb.h>
#include <linux/dma-contiguous.h>
#include <linux/mem_encrypt.h>
#ifdef CONFIG_ISA
# define ISA_DMA_BIT_MASK DMA_BIT_MASK(24)
@ -57,12 +58,12 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
{
return paddr;
return __sme_set(paddr);
}
static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
{
return daddr;
return __sme_clr(daddr);
}
#endif /* CONFIG_X86_DMA_REMAP */

5
arch/x86/include/asm/mem_encrypt.h
View File

@ -34,6 +34,11 @@ void __init sme_early_init(void);
void __init sme_encrypt_kernel(void);
void __init sme_enable(void);
/* Architecture __weak replacement functions */
void __init mem_encrypt_init(void);
void swiotlb_set_mem_attributes(void *vaddr, unsigned long size);
#else /* !CONFIG_AMD_MEM_ENCRYPT */
#define sme_me_mask 0UL

11
arch/x86/kernel/pci-dma.c
View File

@ -93,9 +93,12 @@ again:
if (gfpflags_allow_blocking(flag)) {
page = dma_alloc_from_contiguous(dev, count, get_order(size),
flag);
if (page && page_to_phys(page) + size > dma_mask) {
dma_release_from_contiguous(dev, page, count);
page = NULL;
if (page) {
addr = phys_to_dma(dev, page_to_phys(page));
if (addr + size > dma_mask) {
dma_release_from_contiguous(dev, page, count);
page = NULL;
}
}
}
/* fallback */
@ -104,7 +107,7 @@ again:
if (!page)
return NULL;
addr = page_to_phys(page);
addr = phys_to_dma(dev, page_to_phys(page));
if (addr + size > dma_mask) {
__free_pages(page, get_order(size));

2
arch/x86/kernel/pci-nommu.c
View File

@ -32,7 +32,7 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
enum dma_data_direction dir,
unsigned long attrs)
{
dma_addr_t bus = page_to_phys(page) + offset;
dma_addr_t bus = phys_to_dma(dev, page_to_phys(page)) + offset;
WARN_ON(size == 0);
if (!check_addr("map_single", dev, bus, size))
return NOMMU_MAPPING_ERROR;

15
arch/x86/kernel/pci-swiotlb.c
View File

@ -6,12 +6,14 @@
#include <linux/swiotlb.h>
#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <linux/mem_encrypt.h>
#include <asm/iommu.h>
#include <asm/swiotlb.h>
#include <asm/dma.h>
#include <asm/xen/swiotlb-xen.h>
#include <asm/iommu_table.h>
int swiotlb __read_mostly;
void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
@ -79,8 +81,8 @@ IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
pci_swiotlb_late_init);
/*
* if 4GB or more detected (and iommu=off not set) return 1
* and set swiotlb to 1.
* If 4GB or more detected (and iommu=off not set) or if SME is active
* then set swiotlb to 1 and return 1.
*/
int __init pci_swiotlb_detect_4gb(void)
{
@ -89,6 +91,15 @@ int __init pci_swiotlb_detect_4gb(void)
if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
swiotlb = 1;
#endif
/*
* If SME is active then swiotlb will be set to 1 so that bounce
* buffers are allocated and used for devices that do not support
* the addressing range required for the encryption mask.
*/
if (sme_active())
swiotlb = 1;
return swiotlb;
}
IOMMU_INIT(pci_swiotlb_detect_4gb,

22
arch/x86/mm/mem_encrypt.c
View File

@ -13,11 +13,14 @@
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/swiotlb.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>
#include <asm/setup.h>
#include <asm/bootparam.h>
#include <asm/set_memory.h>
/*
* Since SME related variables are set early in the boot process they must
@ -177,6 +180,25 @@ void __init sme_early_init(void)
protection_map[i] = pgprot_encrypted(protection_map[i]);
}
/* Architecture __weak replacement functions */
void __init mem_encrypt_init(void)
{
if (!sme_me_mask)
return;
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
}
void swiotlb_set_mem_attributes(void *vaddr, unsigned long size)
{
WARN(PAGE_ALIGN(size) != size,
"size is not page-aligned (%#lx)\n", size);
/* Make the SWIOTLB buffer area decrypted */
set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT);
}
void __init sme_encrypt_kernel(void)
{
}

1
include/linux/swiotlb.h
View File

@ -35,6 +35,7 @@ int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
extern unsigned long swiotlb_nr_tbl(void);
unsigned long swiotlb_size_or_default(void);
extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
extern void __init swiotlb_update_mem_attributes(void);
/*
* Enumeration for sync targets

10
init/main.c
View File

@ -488,6 +488,8 @@ void __init __weak thread_stack_cache_init(void)
}
#endif
void __init __weak mem_encrypt_init(void) { }
/*
* Set up kernel memory allocators
*/
@ -641,6 +643,14 @@ asmlinkage __visible void __init start_kernel(void)
*/
locking_selftest();
/*
* This needs to be called before any devices perform DMA
* operations that might use the SWIOTLB bounce buffers. It will
* mark the bounce buffers as decrypted so that their usage will
* not cause "plain-text" data to be decrypted when accessed.
*/
mem_encrypt_init();
#ifdef CONFIG_BLK_DEV_INITRD
if (initrd_start && !initrd_below_start_ok &&
page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {

54
lib/swiotlb.c
View File

@ -30,6 +30,7 @@
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/scatterlist.h>
#include <linux/mem_encrypt.h>
#include <asm/io.h>
#include <asm/dma.h>
@ -155,6 +156,15 @@ unsigned long swiotlb_size_or_default(void)
return size ? size : (IO_TLB_DEFAULT_SIZE);
}
void __weak swiotlb_set_mem_attributes(void *vaddr, unsigned long size) { }
/* For swiotlb, clear memory encryption mask from dma addresses */
static dma_addr_t swiotlb_phys_to_dma(struct device *hwdev,
phys_addr_t address)
{
return __sme_clr(phys_to_dma(hwdev, address));
}
/* Note that this doesn't work with highmem page */
static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
volatile void *address)
@ -183,6 +193,31 @@ void swiotlb_print_info(void)
bytes >> 20, vstart, vend - 1);
}
/*
* Early SWIOTLB allocation may be too early to allow an architecture to
* perform the desired operations. This function allows the architecture to
* call SWIOTLB when the operations are possible. It needs to be called
* before the SWIOTLB memory is used.
*/
void __init swiotlb_update_mem_attributes(void)
{
void *vaddr;
unsigned long bytes;
if (no_iotlb_memory || late_alloc)
return;
vaddr = phys_to_virt(io_tlb_start);
bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
swiotlb_set_mem_attributes(vaddr, bytes);
memset(vaddr, 0, bytes);
vaddr = phys_to_virt(io_tlb_overflow_buffer);
bytes = PAGE_ALIGN(io_tlb_overflow);
swiotlb_set_mem_attributes(vaddr, bytes);
memset(vaddr, 0, bytes);
}
int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
{
void *v_overflow_buffer;
@ -320,6 +355,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
io_tlb_start = virt_to_phys(tlb);
io_tlb_end = io_tlb_start + bytes;
swiotlb_set_mem_attributes(tlb, bytes);
memset(tlb, 0, bytes);
/*
@ -330,6 +366,8 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
if (!v_overflow_buffer)
goto cleanup2;
swiotlb_set_mem_attributes(v_overflow_buffer, io_tlb_overflow);
memset(v_overflow_buffer, 0, io_tlb_overflow);
io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer);
/*
@ -581,7 +619,7 @@ map_single(struct device *hwdev, phys_addr_t phys, size_t size,
return SWIOTLB_MAP_ERROR;
}
start_dma_addr = phys_to_dma(hwdev, io_tlb_start);
start_dma_addr = swiotlb_phys_to_dma(hwdev, io_tlb_start);
return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size,
dir, attrs);
}
@ -702,7 +740,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
goto err_warn;
ret = phys_to_virt(paddr);
dev_addr = phys_to_dma(hwdev, paddr);
dev_addr = swiotlb_phys_to_dma(hwdev, paddr);
/* Confirm address can be DMA'd by device */
if (dev_addr + size - 1 > dma_mask) {
@ -812,10 +850,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
map = map_single(dev, phys, size, dir, attrs);
if (map == SWIOTLB_MAP_ERROR) {
swiotlb_full(dev, size, dir, 1);
return phys_to_dma(dev, io_tlb_overflow_buffer);
return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
}
dev_addr = phys_to_dma(dev, map);
dev_addr = swiotlb_phys_to_dma(dev, map);
/* Ensure that the address returned is DMA'ble */
if (dma_capable(dev, dev_addr, size))
@ -824,7 +862,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
attrs |= DMA_ATTR_SKIP_CPU_SYNC;
swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
return phys_to_dma(dev, io_tlb_overflow_buffer);
return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
}
EXPORT_SYMBOL_GPL(swiotlb_map_page);
@ -958,7 +996,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
sg_dma_len(sgl) = 0;
return 0;
}
sg->dma_address = phys_to_dma(hwdev, map);
sg->dma_address = swiotlb_phys_to_dma(hwdev, map);
} else
sg->dma_address = dev_addr;
sg_dma_len(sg) = sg->length;
@ -1026,7 +1064,7 @@ EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
int
swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
{
return (dma_addr == phys_to_dma(hwdev, io_tlb_overflow_buffer));
return (dma_addr == swiotlb_phys_to_dma(hwdev, io_tlb_overflow_buffer));
}
EXPORT_SYMBOL(swiotlb_dma_mapping_error);
@ -1039,6 +1077,6 @@ EXPORT_SYMBOL(swiotlb_dma_mapping_error);
int
swiotlb_dma_supported(struct device *hwdev, u64 mask)
{
return phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
return swiotlb_phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
}
EXPORT_SYMBOL(swiotlb_dma_supported);