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authorPaolo Bonzini <pbonzini@redhat.com>2016-06-07 18:51:18 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2016-07-05 15:41:26 +0300
commitadd6a0cd1c5ba51b201e1361b05a5df817083618 (patch)
treededa6470d77bbc8b478f4d508927754e8ff38e42 /mm/gup.c
parent92176a8ede577d0ff78ab3298e06701f67ad5f51 (diff)
downloadlinux-add6a0cd1c5ba51b201e1361b05a5df817083618.tar.xz
KVM: MMU: try to fix up page faults before giving up
The vGPU folks would like to trap the first access to a BAR by setting vm_ops on the VMAs produced by mmap-ing a VFIO device. The fault handler then can use remap_pfn_range to place some non-reserved pages in the VMA. This kind of VM_PFNMAP mapping is not handled by KVM, but follow_pfn and fixup_user_fault together help supporting it. The patch also supports VM_MIXEDMAP vmas where the pfns are not reserved and thus subject to reference counting. Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Tested-by: Neo Jia <cjia@nvidia.com> Reported-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/gup.c b/mm/gup.c
index c057784c8444..e3ac22f90fa4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -720,6 +720,7 @@ retry:
}
return 0;
}
+EXPORT_SYMBOL_GPL(fixup_user_fault);
static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
struct mm_struct *mm,