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Diffstat (limited to 'arch/x86/kernel/pci-dma.c')
-rw-r--r--arch/x86/kernel/pci-dma.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 328592fb604..64b838eac18 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -3,6 +3,7 @@
#include <linux/dmar.h>
#include <linux/bootmem.h>
#include <linux/pci.h>
+#include <linux/kmemleak.h>
#include <asm/proto.h>
#include <asm/dma.h>
@@ -32,6 +33,15 @@ int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = 0;
+/*
+ * This variable becomes 1 if iommu=pt is passed on the kernel command line.
+ * If this variable is 1, IOMMU implementations do no DMA ranslation for
+ * devices and allow every device to access to whole physical memory. This is
+ * useful if a user want to use an IOMMU only for KVM device assignment to
+ * guests and not for driver dma translation.
+ */
+int iommu_pass_through __read_mostly;
+
dma_addr_t bad_dma_address __read_mostly = 0;
EXPORT_SYMBOL(bad_dma_address);
@@ -86,6 +96,11 @@ void __init dma32_reserve_bootmem(void)
size = roundup(dma32_bootmem_size, align);
dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
512ULL<<20);
+ /*
+ * Kmemleak should not scan this block as it may not be mapped via the
+ * kernel direct mapping.
+ */
+ kmemleak_ignore(dma32_bootmem_ptr);
if (dma32_bootmem_ptr)
dma32_bootmem_size = size;
else
@@ -145,7 +160,7 @@ again:
return NULL;
addr = page_to_phys(page);
- if (!is_buffer_dma_capable(dma_mask, addr, size)) {
+ if (addr + size > dma_mask) {
__free_pages(page, get_order(size));
if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
@@ -210,6 +225,8 @@ static __init int iommu_setup(char *p)
if (!strncmp(p, "soft", 4))
swiotlb = 1;
#endif
+ if (!strncmp(p, "pt", 2))
+ iommu_pass_through = 1;
gart_parse_options(p);