From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42960) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wzjyk-00037g-4w for qemu-devel@nongnu.org; Wed, 25 Jun 2014 05:59:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wzjyb-0007mE-7j for qemu-devel@nongnu.org; Wed, 25 Jun 2014 05:58:58 -0400 Received: from mga09.intel.com ([134.134.136.24]:61515) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wzjyb-0007lj-2a for qemu-devel@nongnu.org; Wed, 25 Jun 2014 05:58:49 -0400 Message-ID: <53AA9D53.4010407@intel.com> Date: Wed, 25 Jun 2014 17:58:43 +0800 From: "Chen, Tiejun" MIME-Version: 1.0 References: <20140625064545.GB25563@redhat.com> <53AA8404.8040708@intel.com> <20140625082850.GB32652@redhat.com> <53AA8AAB.30100@intel.com> <20140625084347.GE32652@redhat.com> <53AA8CC2.7090406@intel.com> <20140625090420.GG32652@redhat.com> <53AA92F6.1090803@intel.com> <20140625092141.GL32652@redhat.com> <53AA9650.1060503@intel.com> <20140625094455.GB6357@redhat.com> In-Reply-To: <20140625094455.GB6357@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [v5][PATCH 2/5] xen, gfx passthrough: create pseudo intel isa bridge List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: peter.maydell@linaro.org, xen-devel@lists.xensource.com, stefano.stabellini@eu.citrix.com, allen.m.kay@intel.com, qemu-devel@nongnu.org, Kelly.Zytaruk@amd.com, yang.z.zhang@intel.com, anthony@codemonkey.ws, anthony.perard@citrix.com, pbonzini@redhat.com On 2014/6/25 17:44, Michael S. Tsirkin wrote: > On Wed, Jun 25, 2014 at 05:28:48PM +0800, Chen, Tiejun wrote: >> On 2014/6/25 17:21, Michael S. Tsirkin wrote: >>> On Wed, Jun 25, 2014 at 05:14:30PM +0800, Chen, Tiejun wrote: >>>> On 2014/6/25 17:04, Michael S. Tsirkin wrote: >>>>> On Wed, Jun 25, 2014 at 04:48:02PM +0800, Chen, Tiejun wrote: >>>>>> On 2014/6/25 16:43, Michael S. Tsirkin wrote: >>>>>>> On Wed, Jun 25, 2014 at 04:39:07PM +0800, Chen, Tiejun wrote: >>>>>>>>> In fact it's exactly what passthrough does. >>>>>>>>> I wonder if more bits from ./hw/i386/kvm/pci-assign.c >>>>>>>>> can be reused. How do you poke at the host device? sysfs? >>>>>>>> >>>>>>>> Yes, sysfs. >>>>>>>> >>>>>>>> Thanks >>>>>>>> Tiejun >>>>>>> >>>>>>> Then you should be able to re-use large chunks of >>>>>>> ./hw/i386/kvm/pci-assign.c: basically everything >>>>>>> that deals with emulation. >>>>>> >>>>>> Do you mean those hooks to get info from the real device? Xen have its own >>>>>> wrapper, xen_host_pci_get_block(), so we always go there in xen scenario. >>>>>> >>>>>> Thanks >>>>>> Tiejun >>>>> >>>>> Yes and that's not good. We have two pieces of code doing mostly >>>>> identical things slightly differently. >>>>> hw/i386/kvm/pci-assign.c is a bit younger so it's cleaner, >>>>> but these really need to be unified. >>>>> >>>> >>>> Sorry, take a look at this again, >>>> >>>> xen_host_pci_get_block(XenHostPCIDevice *d, int pos, uint8_t *buf, int len) >>>> | >>>> + xen_host_pci_config_read(d, pos, buf, len) >>>> | >>>> + pread(d->config_fd, buf, len, pos) >>>> >>>> I thinks this should be same as kvm. >>>> >>>> Thanks >>>> Tiejun >>> >>> get_block is trivial. >>> >>> I really mean the whole PT infrastructure for >>> - discovering host devices through sysfs >>> - virtualizing devices >>> >>> rom, bars, msi ... >>> the list goes on. >>> >>> logic is mostly the same. >>> >> >> Looks you mean we can unify the entire PT infrastructure between kvm and xen >> inside qemu. But I'm afraid its not easy to do in a short time, so maybe we >> can queue this as next phase. >> >> Thanks >> Tiejun > > I'm afraid once we merge your code, you'll lose interest :) > Currently we have to push this feature into upstream as our first priority, so unless something is really needed to address. Of course I hope this point what we're talking is not such a thing :) But I can promise here I'd like to do this optimization with your guide next :) > At least, don't add duplicate code for ROM. > Let me try this. Thanks Tiejun