From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32920) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpvip-00081g-Vj for qemu-devel@nongnu.org; Thu, 07 Sep 2017 08:15:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpvii-0002eH-8B for qemu-devel@nongnu.org; Thu, 07 Sep 2017 08:15:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44212) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dpvih-0002dy-VG for qemu-devel@nongnu.org; Thu, 07 Sep 2017 08:15:44 -0400 Date: Thu, 7 Sep 2017 13:15:34 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20170907121534.GN2098@work-vm> References: <20170824192730.8440-1-dgilbert@redhat.com> <20170824192730.8440-29-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC v2 28/32] postcopy: Allow shared memory List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Cc: QEMU , Maxime Coquelin , a.perevalov@samsung.com, "Michael S. Tsirkin" , Laurent Vivier , aarcange@redhat.com, Felipe Franciosi , Peter Xu , Juan Quintela * Marc-Andr=E9 Lureau (marcandre.lureau@gmail.com) wrote: > Hi >=20 > On Thu, Aug 24, 2017 at 12:27 PM, Dr. David Alan Gilbert (git) > wrote: > > From: "Dr. David Alan Gilbert" > > > > Now that we have the mechanisms in here, allow shared memory in a > > postcopy. > > > > Note that QEMU can't tell who all the users of shared regions are > > and thus can't tell whether all the users of the shared regions > > have appropriate support for postcopy. Those devices that explicitly > > support shared memory (e.g. vhost-user) must check, but it doesn't > > stop weirder configurations causing problems. > > >=20 > Other users should have their own migration blocker, I guess. Yes, the ones that know about it. The tricky thing is you can add a shared=3Don to any memory object you add; I don't know that the reason it's shared is purely because it's used by vhost-user - for all qemu knows it could be shared with 5 other things as well. > > Signed-off-by: Dr. David Alan Gilbert >=20 > Reviewed-by: Marc-Andr=E9 Lureau Thanks. Dave >=20 >=20 > > --- > > migration/postcopy-ram.c | 6 ------ > > 1 file changed, 6 deletions(-) > > > > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > > index 28791cf1f1..89c3aadda1 100644 > > --- a/migration/postcopy-ram.c > > +++ b/migration/postcopy-ram.c > > @@ -138,12 +138,6 @@ static int test_ramblock_postcopiable(const char= *block_name, void *host_addr, > > RAMBlock *rb =3D qemu_ram_block_by_name(block_name); > > size_t pagesize =3D qemu_ram_pagesize(rb); > > > > - if (qemu_ram_is_shared(rb)) { > > - error_report("Postcopy on shared RAM (%s) is not yet support= ed", > > - block_name); > > - return 1; > > - } > > - > > if (length % pagesize) { > > error_report("Postcopy requires RAM blocks to be a page size= multiple," > > " block %s is 0x" RAM_ADDR_FMT " bytes with a " > > -- > > 2.13.5 > > > > >=20 >=20 >=20 > --=20 > Marc-Andr=E9 Lureau -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK