Revert "KVM: No need to retry for hva_to_pfn_remapped()" (a8387d0b) · Commits · 戴 / test

This reverts commit . If unlocked==true then the vma pointer could be invalidated, so the 2nd follow_pfn() is potentially racy: we do need to get out and redo find_vma_intersection(). Signed-off-by:

Peter Xu <peterx@redhat.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1831,6 +1831,8 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
		r = fixup_user_fault(current, current->mm, addr,
		(write_fault ? FAULT_FLAG_WRITE : 0),
		&unlocked);
		if (unlocked)
		return -EAGAIN;
		if (r)
		return r;

		@@ -1901,12 +1903,15 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
		goto exit;
		}

		retry:
		vma = find_vma_intersection(current->mm, addr, addr + 1);

		if (vma == NULL)
		pfn = KVM_PFN_ERR_FAULT;
		else if (vma->vm_flags & (VM_IO \| VM_PFNMAP)) {
		r = hva_to_pfn_remapped(vma, addr, async, write_fault, writable, &pfn);
		if (r == -EAGAIN)
		goto retry;
		if (r < 0)
		pfn = KVM_PFN_ERR_FAULT;
		} else {

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