Commit 51a5d6e5 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Michael S. Tsirkin
Browse files

libvhost-user+postcopy: Register new regions with the ufd 



When new regions are sent to the client using SET_MEM_TABLE, register
them with the userfaultfd.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 1cba9f6e

contrib/libvhost-user/libvhost-user.c

+34 −0
Original line number Diff line number Diff line
@@ -494,6 +494,40 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) 
        close(vmsg->fds[i]);

    }



    /* TODO: Get address back to QEMU */

    for (i = 0; i < dev->nregions; i++) {

        VuDevRegion *dev_region = &dev->regions[i];

#ifdef UFFDIO_REGISTER

        /* We should already have an open ufd. 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;

        reg_struct.range.start = (uintptr_t)dev_region->mmap_addr;

        reg_struct.range.len = dev_region->size + dev_region->mmap_offset;

        reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;



        if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER, &reg_struct)) {

            vu_panic(dev, "%s: Failed to userfault region %d "

                          "@%p + size:%zx offset: %zx: (ufd=%d)%s\n",

                     __func__, i,

                     dev_region->mmap_addr,

                     dev_region->size, dev_region->mmap_offset,

                     dev->postcopy_ufd, strerror(errno));

            return false;

        }

        if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) {

            vu_panic(dev, "%s Region (%d) doesn't support COPY",

                     __func__, i);

            return false;

        }

        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 */

#endif

    }



    return false;

}