From 9d8c3af31607819a61011d746e861b8096ac9761 Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Tue, 8 Aug 2017 13:29:27 -0700 Subject: [PATCH] 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 To: linux-kernel@vger.kernel.org> Cc: iommu@lists.linux-foundation.org Cc: David Woodhouse Cc: Jacob Pan Cc: Ashok Raj Signed-off-by: Ashok Raj Reported-by: Sudeep Dutt Acked-by: David Woodhouse Signed-off-by: Joerg Roedel --- 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 f167c0d84ebf..0c9f0773601d 100644 --- a/drivers/iommu/intel-svm.c +++ b/drivers/iommu/intel-svm.c @@ -24,6 +24,7 @@ #include #include #include +#include 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) -- 2.39.5