From 9d8c3af31607819a61011d746e861b8096ac9761 Mon Sep 17 00:00:00 2001
From: Ashok Raj <ashok.raj@intel.com>
Date: Tue, 8 Aug 2017 13:29:27 -0700
Subject: iommu/vt-d: IOMMU Page Request needs to check if address is
canonical.
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 <joro@8bytes.org>
To: linux-kernel@vger.kernel.org>
Cc: iommu@lists.linux-foundation.org
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jacob Pan <jacob.jun.pan@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Reported-by: Sudeep Dutt <sudeep.dutt@intel.com>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/intel-svm.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
(limited to 'drivers/iommu/intel-svm.c')
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index f167c0d84ebf..0c9f0773601d 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)
--
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