From c40c0463413b941c13fe5f99a90c02d7d6584828 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Tue, 7 Feb 2023 15:57:11 -0500 Subject: util/userfaultfd: Support /dev/userfaultfd Teach QEMU to use /dev/userfaultfd when it existed and fallback to the system call if either it's not there or doesn't have enough permission. Firstly, as long as the app has permission to access /dev/userfaultfd, it always have the ability to trap kernel faults which QEMU mostly wants. Meanwhile, in some context (e.g. containers) the userfaultfd syscall can be forbidden, so it can be the major way to use postcopy in a restricted environment with strict seccomp setup. Signed-off-by: Peter Xu Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- util/trace-events | 1 + 1 file changed, 1 insertion(+) (limited to 'util/trace-events') diff --git a/util/trace-events b/util/trace-events index c8f53d7..16f78d8 100644 --- a/util/trace-events +++ b/util/trace-events @@ -93,6 +93,7 @@ qemu_vfio_region_info(const char *desc, uint64_t region_ofs, uint64_t region_siz qemu_vfio_pci_map_bar(int index, uint64_t region_ofs, uint64_t region_size, int ofs, void *host) "map region bar#%d addr 0x%"PRIx64" size 0x%"PRIx64" ofs 0x%x host %p" #userfaultfd.c +uffd_detect_open_mode(int mode) "%d" uffd_query_features_nosys(int err) "errno: %i" uffd_query_features_api_failed(int err) "errno: %i" uffd_create_fd_nosys(int err) "errno: %i" -- cgit v1.1