From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v2] kvm: Disable MSI/MSI-X in assigned device reset path Date: Mon, 16 Apr 2012 22:47:54 +0300 Message-ID: <20120416194753.GD20294@redhat.com> References: <20120405033450.25661.68810.stgit@bling.home> <1334584997.3112.8.camel@bling.home> <20120416150640.GB13713@redhat.com> <1334603276.3112.55.camel@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, Avi Kivity , Marcelo Tosatti , jan.kiszka@siemens.com, jbaron@redhat.com To: Alex Williamson Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32372 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753941Ab2DPTrq (ORCPT ); Mon, 16 Apr 2012 15:47:46 -0400 Content-Disposition: inline In-Reply-To: <1334603276.3112.55.camel@bling.home> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Apr 16, 2012 at 01:07:56PM -0600, Alex Williamson wrote: > On Mon, 2012-04-16 at 18:06 +0300, Michael S. Tsirkin wrote: > > On Mon, Apr 16, 2012 at 08:03:17AM -0600, Alex Williamson wrote: > > > The discussion on this patch seems to have fizzled, with no clear short > > > term solution. > > > > I think we are in concensus, it's just that there are > > multiple bugs still left to fix. > > > > First, we need to prevent guest from touching command > > register except for the bus master bit. Something like > > the below? Compiled only. > > > > device-assignment: don't touch pci command register > > > > Real command register is under kernel control: > > it includes bits for triggering SERR, marking > > BARs as invalid and such which are under host > > kernel control. Don't touch any except bus master > > which is ok to put under guest control. > > > > Signed-off-by: Michael S. Tsirkin > > > > --- > > diff --git a/hw/device-assignment.c b/hw/device-assignment.c > > index 89823f1..9ebce49 100644 > > --- a/hw/device-assignment.c > > +++ b/hw/device-assignment.c > > @@ -501,7 +501,6 @@ static int get_real_device(AssignedDevice *pci_dev, uint16_t r_seg, > > FILE *f; > > unsigned long long start, end, size, flags; > > uint16_t id; > > - struct stat statbuf; > > PCIRegion *rp; > > PCIDevRegions *dev = &pci_dev->real_device; > > > > @@ -610,12 +609,8 @@ again: > > pci_dev->dev.config[2] = id & 0xff; > > pci_dev->dev.config[3] = (id & 0xff00) >> 8; > > > > - /* dealing with virtual function device */ > > - snprintf(name, sizeof(name), "%sphysfn/", dir); > > - if (!stat(name, &statbuf)) { > > - /* always provide the written value on readout */ > > - assigned_dev_emulate_config_read(pci_dev, PCI_COMMAND, 2); > > - } > > + /* Pass bus master writes to device. */ > > + pci_dev->emulate_config_write[PCI_COMMAND] &= ~PCI_COMMAND_MASTER; > > > > dev->region_number = r; > > return 0; > > @@ -782,14 +777,6 @@ static int assign_device(AssignedDevice *dev) > > "cause host memory corruption if the device issues DMA write " > > "requests!\n"); > > } > > - if (dev->features & ASSIGNED_DEVICE_SHARE_INTX_MASK && > > - kvm_has_intx_set_mask()) { > > - assigned_dev_data.flags |= KVM_DEV_ASSIGN_PCI_2_3; > > This doesn't look right ^^^, we'll never make use of host side INTx > disable support that way. Thanks, > > Alex Right.