From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH v4] libxl: Add AHCI support for upstream qemu Date: Thu, 9 Jul 2015 11:26:10 +0100 Message-ID: <1436437570.23508.96.camel@citrix.com> References: <1436365865-4545-1-git-send-email-fabio.fantoni@m2r.biz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1436365865-4545-1-git-send-email-fabio.fantoni@m2r.biz> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Fabio Fantoni Cc: xen-devel@lists.xensource.com, wei.liu2@citrix.com, Stefano.Stabellini@eu.citrix.com, George.Dunlap@eu.citrix.com, Ian.Jackson@eu.citrix.com, Paul.Durrant@citrix.com, anthony.perard@citrix.com List-Id: xen-devel@lists.xenproject.org On Wed, 2015-07-08 at 16:31 +0200, Fabio Fantoni wrote: > Usage: > hdtype=ide|ahci (default=ide) > > If hdtype=ahci adds ich9 disk controller in ahci mode and uses it with > upstream qemu to emulate disks instead of ide. > It doesn't support cdroms which still using ide (cdroms will use > "-device ide-cd" as new qemu parameter) > Ahci requires new qemu parameter but for now other emulated disks cases > remains with old ones (I did it in other patch, not needed by this one) > I did it as libxl parameter disabled by default to avoid possible > problems: > - with save/restore/migration (restoring with ahci a domU that was with > ide instead) > - windows < 8 without pv drivers (a registry key change is needed for > AHCI<->IDE change FWIK to avoid possible blue screen) > - windows XP or older that many not support ahci by default. > Setting AHCI with libxl parameter and default to disabled seems the best > solution. > AHCI increase hvm domUs boot performance. On linux hvm domU I saw up to > only 20% of the previous total boot time, whereas boot time decrease a > lot on W7 domUs for most of boots I have done. Small difference in boot > time compared to ide mode on W8 and newer (probably other xen > improvements or fixes are needed not ahci related) > > Signed-off-by: Fabio Fantoni > > --- > > Changes in v4: > - libxl.h: LIBXL_HAVE_AHCI->LIBXL_HAVE_HVM_AHCI In retrospect this should have been LIBXL_HAVE_HVM_HDTYPE. Since the above was my suggestion if you agree I can make that simple change as I commit. Acked-by: Ian Campbell Ian.