From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=60389 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OOWp0-00038i-Vb for qemu-devel@nongnu.org; Tue, 15 Jun 2010 10:09:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OOWov-0005qq-62 for qemu-devel@nongnu.org; Tue, 15 Jun 2010 10:08:54 -0400 Received: from mail-gy0-f173.google.com ([209.85.160.173]:39257) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OOWov-0005qc-2k for qemu-devel@nongnu.org; Tue, 15 Jun 2010 10:08:53 -0400 Received: by gyd5 with SMTP id 5so3337688gyd.4 for ; Tue, 15 Jun 2010 07:08:52 -0700 (PDT) Message-ID: <4C178980.4020202@codemonkey.ws> Date: Tue, 15 Jun 2010 09:09:04 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 0/5] Migration subsections (and ide as example) References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: qemu-devel@nongnu.org On 06/15/2010 08:31 AM, Juan Quintela wrote: > Hi > > At the end, here is the migration subsections implementation. As an example I ported the last > two ide changes to migration to work with subsections. Notes: > > - subsections > I went for qemu_peek_byte() insteadof adding a subsection part in > qemu_loadvm_state() due to two reasons: > - it makes mandatory that subsections came after sections (better for error messages) > - it makes post_load() for the section to be run after subsections are loaded. > I think that running section post_load() and then subsections can make for some subtle > errors. > How does it works? > We have a new array of subsections at the end of each section (it can be NULL). > Each subsection is composed of VMStateDescription and a test function. test function > checks if subsection is needed or not. if needed, it is just emmited. > On load, we peek to see if after a section is loaded, if there is any subsection > at the end, and if so, we search for it on this section subsections. > > > - ide: 1st revert is not clear because there has been posterior changes that I honored. > only change done is that ide_dummy_transfer_stop to transfer_end_table for it to be > complete. > > - testing. In normal operation this code is not triggered (one of the reason for not wanting to > sent it in the 1st place). I used patch attached at the end to trigger it. > > Commetnts? > Obviously, we can't change IDE like this but the implementation looks pretty sane. Can you add something to docs/ that explains how this works? My only concern is that the code doesn't make it obvious what a subsection is, when to use it, and why it's safe from an implementation perspective. Very nice solution though. Regards, Anthony Liguori > Later, Juan. > > > Juan Quintela (5): > Revert "ide save/restore pio/atapi cmd transfer fields and io buffer" > Revert "ide save/restore current transfer fields" > vmstate: add subsections code > ide: fix migration in the middle of pio operation > ide: fix migration in the middle of a bmdma transfer > > hw/hw.h | 6 ++++ > hw/ide/core.c | 72 ++++++++++++++++++++++++++++++++------------- > hw/ide/pci.c | 38 ++++++++++++++++++++---- > savevm.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 4 files changed, 178 insertions(+), 28 deletions(-) > > > diff --git a/hw/ide/core.c b/hw/ide/core.c > index 59341a1..a4e6b82 100644 > --- a/hw/ide/core.c > +++ b/hw/ide/core.c > @@ -421,6 +421,15 @@ static void ide_sector_read(IDEState *s) > ide_set_irq(s->bus); > ide_set_sector(s, sector_num + n); > s->nsector -= n; > + if ((s->status& DRQ_STAT)) { > + static int val = 1; > + if (((val++) == 1000)) { > + qemu_aio_flush(); > + vm_stop(0); > + printf("stopped %d ide_ioport_readaaa\n", val); > + } > + } > + > } > } > > @@ -2744,6 +2753,14 @@ static int ide_drive_pio_post_load(void *opaque, int version_id) > s->data_ptr = s->io_buffer + s->cur_io_buffer_offset; > s->data_end = s->data_ptr + s->cur_io_buffer_len; > > + printf("addr %p: status %d\n", s, s->status& DRQ_STAT); > + printf("\tdata_ptr %p\n", s->data_ptr); > + printf("\tdata_end %p\n", s->data_end); > + printf("\tio_buffer %p\n", s->io_buffer); > + printf("\treq_nb_sectors %d\n", s->req_nb_sectors); > + printf("\tidx %d\n", transfer_end_table_idx(s->end_transfer_func)); > + printf("\telementary_transfer_size %d\n", s->elementary_transfer_size); > + printf("\tpacket_transfer_size %d\n", s->packet_transfer_size); > return 0; > } > > @@ -2763,6 +2780,15 @@ static void ide_drive_pio_pre_save(void *opaque) > } else { > s->end_transfer_fn_idx = idx; > } > + > + printf("addr %p: status %d\n", s, s->status& DRQ_STAT); > + printf("\tdata_ptr %p\n", s->data_ptr); > + printf("\tdata_end %p\n", s->data_end); > + printf("\tio_buffer %p\n", s->io_buffer); > + printf("\treq_nb_sectors %d\n", s->req_nb_sectors); > + printf("\tidx %d\n", transfer_end_table_idx(s->end_transfer_func)); > + printf("\telementary_transfer_size %d\n", s->elementary_transfer_size); > + printf("\tpacket_transfer_size %d\n", s->packet_transfer_size); > } > > static bool ide_drive_pio_state_needed(void *opaque) > >