Page Request from devices that support device-tlb would request translation
to pre-cache them in device to avoid overhead of IOMMU lookups.
IOMMU needs to check for canonicallity of the address before performing
page-fault processing.
To: Joerg Roedel <j...@8bytes.org>
To: linux-kernel@vger.kernel.org>
Cc: io...@lists-foundation.org
Cc: David Woodhouse <dw...@infradead.org>
Cc: Jacob Pan <jacob.jun....@intel.com>
Cc: Ashok Raj <ashok....@intel.com>
Signed-off-by: Ashok Raj <ashok....@intel.com>
Reported-by: Sudeep Dutt <sudeep.d...@intel.com>
---
drivers/iommu/intel-svm.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index f167c0d..0c9f077 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -24,6 +24,7 @@
#include <linux/pci-ats.h>
#include <linux/dmar.h>
#include <linux/interrupt.h>
+#include <asm/page.h>
static irqreturn_t prq_event_thread(int irq, void *d);
@@ -555,6 +556,14 @@ static bool access_error(struct vm_area_struct *vma,
struct page_req_dsc *req)
return (requested & ~vma->vm_flags) != 0;
}
+static bool is_canonical_address(u64 addr)
+{
+ int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
+ long saddr = (long) addr;
+
+ return (((saddr << shift) >> shift) == saddr);
+}
+
static irqreturn_t prq_event_thread(int irq, void *d)
{
struct intel_iommu *iommu = d;
@@ -612,6 +621,11 @@ static irqreturn_t prq_event_thread(int irq, void *d)
/* If the mm is already defunct, don't handle faults. */
if (!mmget_not_zero(svm->mm))
goto bad_req;
+
+ /* If address is not canonical, return invalid response */
+ if (!is_canonical_address(address))
+ goto bad_req;
+
down_read(&svm->mm->mmap_sem);
vma = find_extend_vma(svm->mm, address);
if (!vma || address < vma->vm_start)
--
2.7.4
