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Revert "KVM: No need to retry for hva_to_pfn_remapped()"

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This reverts commit 5b494aea13.
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>
This commit is contained in:
Paolo Bonzini 2020-05-29 05:42:55 -04:00
parent cc440cdad5
commit a8387d0b47
1 changed files with 5 additions and 0 deletions
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5
virt/kvm/kvm_main.c
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@ -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 {