Commit 41311242 authored by Alex Williamson's avatar Alex Williamson
Browse files

vfio/type1: Support faulting PFNMAP vmas 



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: default avatarPeter Xu <peterx@redhat.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent b9bbe6ed

drivers/vfio/vfio_iommu_type1.c

+33 −3
Original line number Diff line number Diff line
@@ -317,6 +317,32 @@ static int put_pfn(unsigned long pfn, int prot) 
	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)

{
@@ -339,12 +365,16 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, 


	vaddr = untagged_addr(vaddr);



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;

	}

done:

	up_read(&mm->mmap_sem);

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