From: "Dr. David Alan Gilbert" <address@hidden>
When new regions are sent to the client using SET_MEM_TABLE, register
them with the userfaultfd.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
contrib/libvhost-user/libvhost-user.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/contrib/libvhost-user/libvhost-user.c
b/contrib/libvhost-user/libvhost-user.c
index 6de339fb7a..be7470e3a9 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -450,6 +450,39 @@ vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
dev_region->mmap_addr);
}
+ if (dev->postcopy_listening) {
+ /* We should already have an open ufd need to mark each memory
+ * range as ufd.
+ * Note: Do we need any madvises? Well it's not been accessed
+ * yet, still probably need no THP to be safe, discard to be safe?
+ */
+ struct uffdio_register reg_struct;
+ /* Note: We might need to go back to using mmap_addr and
+ * len + mmap_offset for * huge pages, but then we do hope not to
+ * see accesses in that area below the offset
+ */
+ reg_struct.range.start = (uintptr_t)(dev_region->mmap_addr +
+ dev_region->mmap_offset);
+ reg_struct.range.len = dev_region->size;
+ reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
+
+ if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER, ®_struct)) {
+ vu_panic(dev, "%s: Failed to userfault region %d:
(ufd=%d)%s\n",
+ __func__, i, strerror(errno), dev->postcopy_ufd);
+ continue;
+ }
+ if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) {
+ vu_panic(dev, "%s Region (%d) doesn't support COPY",
+ __func__, i);
+ continue;
+ }
+ DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
+ __func__, i, reg_struct.range.start, reg_struct.range.len);
+ /* TODO: Stash 'zero' support flags somewhere */
+ /* TODO: Get address back to QEMU */
+
+ }
+
close(vmsg->fds[i]);
}