This is a note to let you know that I've just added the patch titled
vfio/type1: Support faulting PFNMAP vmas
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vfio-type1-support-faulting-pfnmap-vmas.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 41311242221e3482b20bfed10fa4d9db98d87016 Mon Sep 17 00:00:00 2001
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
Date: Tue, 28 Apr 2020 17:02:24 -0600
Subject: vfio/type1: Support faulting PFNMAP vmas
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
commit 41311242221e3482b20bfed10fa4d9db98d87016 upstream.
With conversion to follow_pfn(), DMA mapping a PFNMAP range depends on
the range being faulted into the vma. Add support to manually provide
that, in the same way as done on KVM with hva_to_pfn_remapped().
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
[Ajay: Regenerated the patch for v4.14]
Signed-off-by: Ajay Kaher <akaher@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/vfio/vfio_iommu_type1.c | 36 +++++++++++++++++++++++++++++++++---
1 file changed, 33 insertions(+), 3 deletions(-)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -336,6 +336,32 @@ static int put_pfn(unsigned long pfn, in
return 0;
}
+static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
+ unsigned long vaddr, unsigned long *pfn,
+ bool write_fault)
+{
+ int ret;
+
+ ret = follow_pfn(vma, vaddr, pfn);
+ if (ret) {
+ bool unlocked = false;
+
+ ret = fixup_user_fault(NULL, mm, vaddr,
+ FAULT_FLAG_REMOTE |
+ (write_fault ? FAULT_FLAG_WRITE : 0),
+ &unlocked);
+ if (unlocked)
+ return -EAGAIN;
+
+ if (ret)
+ return ret;
+
+ ret = follow_pfn(vma, vaddr, pfn);
+ }
+
+ return ret;
+}
+
static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
int prot, unsigned long *pfn)
{
@@ -375,12 +401,16 @@ static int vaddr_get_pfn(struct mm_struc
down_read(&mm->mmap_sem);
+retry:
vma = find_vma_intersection(mm, vaddr, vaddr + 1);
if (vma && vma->vm_flags & VM_PFNMAP) {
- if (!follow_pfn(vma, vaddr, pfn) &&
- is_invalid_reserved_pfn(*pfn))
- ret = 0;
+ ret = follow_fault_pfn(vma, mm, vaddr, pfn, prot & IOMMU_WRITE);
+ if (ret == -EAGAIN)
+ goto retry;
+
+ if (!ret && !is_invalid_reserved_pfn(*pfn))
+ ret = -EFAULT;
}
up_read(&mm->mmap_sem);
Patches currently in stable-queue which might be from alex.williamson@xxxxxxxxxx are
queue-4.14/vfio-type1-support-faulting-pfnmap-vmas.patch
queue-4.14/vfio-pci-fault-mmaps-to-enable-vma-tracking.patch
queue-4.14/vfio-pci-fix-sr-iov-vf-handling-with-mmio-blocking.patch
queue-4.14/vfio-pci-invalidate-mmaps-and-block-mmio-access-on-disabled-memory.patch
