From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55534) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmcNA-000637-JJ for qemu-devel@nongnu.org; Tue, 20 May 2014 01:14:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WmcN6-00010k-R4 for qemu-devel@nongnu.org; Tue, 20 May 2014 01:13:56 -0400 Received: from mga03.intel.com ([143.182.124.21]:26152) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmcN6-00010e-KC for qemu-devel@nongnu.org; Tue, 20 May 2014 01:13:52 -0400 From: "Chen, Tiejun" Date: Tue, 20 May 2014 05:13:45 +0000 Message-ID: References: <1400237624-8505-1-git-send-email-tiejun.chen@intel.com> <1400237624-8505-7-git-send-email-tiejun.chen@intel.com> <20140516143511.GE3154@phenom.dumpdata.com> <20140519133400.GA3152@phenom.dumpdata.com> In-Reply-To: <20140519133400.GA3152@phenom.dumpdata.com> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Konrad Rzeszutek Wilk , "Zhang, Yang Z" Cc: "peter.maydell@linaro.org" , "xen-devel@lists.xensource.com" , "mst@redhat.com" , "stefano.stabellini@eu.citrix.com" , "Kay, Allen M" , "Kelly.Zytaruk@amd.com" , "qemu-devel@nongnu.org" , "anthony@codemonkey.ws" , "anthony.perard@citrix.com" > -----Original Message----- > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > Sent: Monday, May 19, 2014 9:34 PM > To: Zhang, Yang Z > Cc: Chen, Tiejun; anthony.perard@citrix.com; stefano.stabellini@eu.citrix= .com; > mst@redhat.com; Kelly.Zytaruk@amd.com; peter.maydell@linaro.org; > xen-devel@lists.xensource.com; weidong.han@intel.com; Kay, Allen M; > qemu-devel@nongnu.org; jean.guyader@eu.citrix.com; > anthony@codemonkey.ws > Subject: Re: [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support In= tel > IGD passthrough with VT-D >=20 > On Mon, May 19, 2014 at 12:58:50AM +0000, Zhang, Yang Z wrote: > > Konrad Rzeszutek Wilk wrote on 2014-05-16: > > > On Fri, May 16, 2014 at 06:53:42PM +0800, Tiejun Chen wrote: > > > > Some registers of Intel IGD are mapped in host bridge, so it needs > > > > to passthrough these registers of physical host bridge to guest > > > > because emulated host bridge in guest doesn't have these mappings. > > > > Thanks for your review for the whole series patch. >=20 > Sure thing! >=20 > .. snip.. > > > > +write_default: > > > > + pci_default_write_config(pci_dev, config_addr, val, len); > > > > > > > > > and we just allow it through. But what happens if the guest decides > > > to change the BAR sizes? Or fiddle with the GTT? > > > > > > Ouch. That really looks dangerous - or maybe I am too paranoid? > > > > > > > I do not quite understand your concern. We only pass through PAVPC to > physical host bridge. The others are handled by current logic. We don't c= hange > any of it. So what problem will be exposed by this patch? >=20 > Ah, I assumed that pci_default_write_config would be writting everything > without any checks. But it looks to be doing the right thing and just set= s the > emulated values. >=20 > Could we just add comment saying that it writes to the emulated values? T= hat > way it won't trip folks. diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c index 1342f4f..5e5e3d5 100644 --- a/hw/xen/xen_pt_graphics.c +++ b/hw/xen/xen_pt_graphics.c @@ -367,6 +367,7 @@ void igd_pci_write(PCIDevice *pci_dev, uint32_t config_= addr, case 0x58: /* PAVPC Offset */ break; default: + /* Just sets the emulated values. */ goto write_default; } =20 @@ -427,6 +428,7 @@ uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t conf= ig_addr, int len) case 0xa8: /* SNB: base of GTT stolen memory */ break; default: + /* Just gets the emulated values. */ goto read_default; } Thanks Tiejun From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Tiejun" Subject: Re: [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D Date: Tue, 20 May 2014 05:13:45 +0000 Message-ID: References: <1400237624-8505-1-git-send-email-tiejun.chen@intel.com> <1400237624-8505-7-git-send-email-tiejun.chen@intel.com> <20140516143511.GE3154@phenom.dumpdata.com> <20140519133400.GA3152@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20140519133400.GA3152@phenom.dumpdata.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org To: Konrad Rzeszutek Wilk , "Zhang, Yang Z" Cc: "peter.maydell@linaro.org" , "xen-devel@lists.xensource.com" , "mst@redhat.com" , "stefano.stabellini@eu.citrix.com" , "Kay, Allen M" , "Kelly.Zytaruk@amd.com" , "qemu-devel@nongnu.org" , "anthony@codemonkey.ws" , "anthony.perard@citrix.com" List-Id: xen-devel@lists.xenproject.org > -----Original Message----- > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > Sent: Monday, May 19, 2014 9:34 PM > To: Zhang, Yang Z > Cc: Chen, Tiejun; anthony.perard@citrix.com; stefano.stabellini@eu.citrix= .com; > mst@redhat.com; Kelly.Zytaruk@amd.com; peter.maydell@linaro.org; > xen-devel@lists.xensource.com; weidong.han@intel.com; Kay, Allen M; > qemu-devel@nongnu.org; jean.guyader@eu.citrix.com; > anthony@codemonkey.ws > Subject: Re: [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support In= tel > IGD passthrough with VT-D >=20 > On Mon, May 19, 2014 at 12:58:50AM +0000, Zhang, Yang Z wrote: > > Konrad Rzeszutek Wilk wrote on 2014-05-16: > > > On Fri, May 16, 2014 at 06:53:42PM +0800, Tiejun Chen wrote: > > > > Some registers of Intel IGD are mapped in host bridge, so it needs > > > > to passthrough these registers of physical host bridge to guest > > > > because emulated host bridge in guest doesn't have these mappings. > > > > Thanks for your review for the whole series patch. >=20 > Sure thing! >=20 > .. snip.. > > > > +write_default: > > > > + pci_default_write_config(pci_dev, config_addr, val, len); > > > > > > > > > and we just allow it through. But what happens if the guest decides > > > to change the BAR sizes? Or fiddle with the GTT? > > > > > > Ouch. That really looks dangerous - or maybe I am too paranoid? > > > > > > > I do not quite understand your concern. We only pass through PAVPC to > physical host bridge. The others are handled by current logic. We don't c= hange > any of it. So what problem will be exposed by this patch? >=20 > Ah, I assumed that pci_default_write_config would be writting everything > without any checks. But it looks to be doing the right thing and just set= s the > emulated values. >=20 > Could we just add comment saying that it writes to the emulated values? T= hat > way it won't trip folks. diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c index 1342f4f..5e5e3d5 100644 --- a/hw/xen/xen_pt_graphics.c +++ b/hw/xen/xen_pt_graphics.c @@ -367,6 +367,7 @@ void igd_pci_write(PCIDevice *pci_dev, uint32_t config_= addr, case 0x58: /* PAVPC Offset */ break; default: + /* Just sets the emulated values. */ goto write_default; } =20 @@ -427,6 +428,7 @@ uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t conf= ig_addr, int len) case 0xa8: /* SNB: base of GTT stolen memory */ break; default: + /* Just gets the emulated values. */ goto read_default; } Thanks Tiejun