From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56439) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WrsUo-0003wL-6R for qemu-devel@nongnu.org; Tue, 03 Jun 2014 13:27:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WrsUj-0001Hv-1Z for qemu-devel@nongnu.org; Tue, 03 Jun 2014 13:27:34 -0400 Date: Tue, 3 Jun 2014 18:27:15 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20140603172714.GH3017@work-vm> References: <1401485884-25500-1-git-send-email-pl@kamp.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1401485884-25500-1-git-send-email-pl@kamp.de> Subject: Re: [Qemu-devel] [PATCH RESEND] migration: catch unknown flags in ram_load List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: pbonzini@redhat.com, qemu-stable@nongnu.org, qemu-devel@nongnu.org, quintela@redhat.com * Peter Lieven (pl@kamp.de) wrote: > if a saved vm has unknown flags in the memory data qemu > currently simply ignores this flag and continues which > yields in an unpredictable result. > > this patch catches all unknown flags and > aborts the loading of the vm. Yes, I think that's quite nice - the only thing I'd add which would help a little is an error_report() in the case where you have invalid flags to let you know that's the reason for the EINVAL. (Having spent the day tracking down migration bugs...) Reviewed-by: Dr. David Alan Gilbert > > CC: qemu-stable@nongnu.org > Signed-off-by: Peter Lieven > Reviewed-by: Eric Blake > --- > arch_init.c | 35 ++++++++++++++++------------------- > 1 file changed, 16 insertions(+), 19 deletions(-) > > diff --git a/arch_init.c b/arch_init.c > index 995f56d..322d129 100644 > --- a/arch_init.c > +++ b/arch_init.c > @@ -1030,17 +1030,15 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > { > ram_addr_t addr; > int flags, ret = 0; > - int error; > static uint64_t seq_iter; > > seq_iter++; > > if (version_id != 4) { > ret = -EINVAL; > - goto done; > } > > - do { > + while (!ret) { > addr = qemu_get_be64(f); > > flags = addr & ~TARGET_PAGE_MASK; > @@ -1069,7 +1067,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > " in != " RAM_ADDR_FMT "\n", id, length, > block->length); > ret = -EINVAL; > - goto done; > } > break; > } > @@ -1079,21 +1076,21 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > fprintf(stderr, "Unknown ramblock \"%s\", cannot " > "accept migration\n", id); > ret = -EINVAL; > - goto done; > + } > + if (ret) { > + break; > } > > total_ram_bytes -= length; > } > - } > - > - if (flags & RAM_SAVE_FLAG_COMPRESS) { > + } else if (flags & RAM_SAVE_FLAG_COMPRESS) { > void *host; > uint8_t ch; > > host = host_from_stream_offset(f, addr, flags); > if (!host) { > ret = -EINVAL; > - goto done; > + break; > } > > ch = qemu_get_byte(f); > @@ -1104,7 +1101,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > host = host_from_stream_offset(f, addr, flags); > if (!host) { > ret = -EINVAL; > - goto done; > + break; > } > > qemu_get_buffer(f, host, TARGET_PAGE_SIZE); > @@ -1112,24 +1109,24 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > void *host = host_from_stream_offset(f, addr, flags); > if (!host) { > ret = -EINVAL; > - goto done; > + break; > } > > if (load_xbzrle(f, addr, host) < 0) { > ret = -EINVAL; > - goto done; > + break; > } > } else if (flags & RAM_SAVE_FLAG_HOOK) { > ram_control_load_hook(f, flags); > + } else if (flags & RAM_SAVE_FLAG_EOS) { > + break; > + } else { > + ret = -EINVAL; > + break; > } > - error = qemu_file_get_error(f); > - if (error) { > - ret = error; > - goto done; > - } > - } while (!(flags & RAM_SAVE_FLAG_EOS)); > + ret = qemu_file_get_error(f); > + } > > -done: > DPRINTF("Completed load of VM with exit code %d seq iteration " > "%" PRIu64 "\n", ret, seq_iter); > return ret; > -- > 1.7.9.5 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK