From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35257) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UwGkb-0005Di-CV for qemu-devel@nongnu.org; Mon, 08 Jul 2013 15:05:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UwGkZ-0003ar-Ql for qemu-devel@nongnu.org; Mon, 08 Jul 2013 15:05:29 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:50478) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UwGkZ-0003aK-IS for qemu-devel@nongnu.org; Mon, 08 Jul 2013 15:05:27 -0400 Received: from /spool/local by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 8 Jul 2013 13:05:17 -0600 From: Anthony Liguori In-Reply-To: <52CC13CE-9911-4C4E-98C9-B792187F9760@suse.de> References: <1372315560-5478-1-git-send-email-aik@ozlabs.ru> <1372315560-5478-12-git-send-email-aik@ozlabs.ru> <87mwpwzya6.fsf@codemonkey.ws> <52CC13CE-9911-4C4E-98C9-B792187F9760@suse.de> Date: Mon, 08 Jul 2013 14:01:28 -0500 Message-ID: <87ip0k3mgn.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Re: [Qemu-devel] [PATCH 11/17] pseries: savevm support for pseries machine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: Alexey Kardashevskiy , qemu-devel@nongnu.org, qemu-ppc@nongnu.org, Paolo Bonzini , Paul Mackerras , David Gibson Alexander Graf writes: > On 08.07.2013, at 20:45, Anthony Liguori wrote: > >> Alexey Kardashevskiy writes: >> >>> From: David Gibson >>> >>> This adds the necessary pieces to implement savevm / migration for the >>> pseries machine. The most complex part here is migrating the hash >>> table - for the paravirtualized pseries machine the guest's hash page >>> table is not stored within guest memory, but externally and the guest >>> accesses it via hypercalls. >>> >>> This patch uses a hypervisor reserved bit of the HPTE as a dirty bit >>> (tracking changes to the HPTE itself, not the page it references). >>> This is used to implement a live migration style incremental save and >>> restore of the hash table contents. >>> >>> In addition it adds VMStateDescription information to save and restore >>> the (few) remaining pieces of state information needed by the pseries >>> machine. >>> >>> Signed-off-by: David Gibson >>> Signed-off-by: Alexey Kardashevskiy >> >> I vaguely recall making the suggestion to use a live section like this. >> How large is the HTAB typically? > > The default for HV KVM is at 16MB IIRC. And if I recall since it's a hash table, updates are random access and not at all page aligned making using qemu ram quite unusable for this purpose. I guess: Reviewed-by: Anthony Liguori Regards, Anthony Liguori > > > Alex