KVM: No need to retry for hva_to_pfn_remapped()

hva_to_pfn_remapped() calls fixup_user_fault(), which has already
handled the retry gracefully.  Even if "unlocked" is set to true, it
means that we've got a VM_FAULT_RETRY inside fixup_user_fault(),
however the page fault has already retried and we should have the pfn
set correctly.  No need to do that again.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20200416155906.267462-1-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e12317f..bef3d8d 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1831,8 +1831,6 @@ 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;
 
@@ -1903,15 +1901,12 @@ 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 {