From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [BUG] pci-passthrough generates "xen:events: Failed to obtain physical IRQ" for some devices Date: Wed, 3 Feb 2016 10:26:58 -0500 Message-ID: <20160203152657.GE20732@char.us.oracle.com> References: <20160127183005.GB3134@char.us.oracle.com> <1454323426.28781.73.camel@citrix.com> <20160201145053.GA21826@char.us.oracle.com> <20160203142230.GC24446@mail-itl> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="mP3DRpeJDSE+ciuQ" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160203142230.GC24446@mail-itl> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Marek =?iso-8859-1?Q?Marczykowski-G=F3recki?= Cc: Tommi Airikka , Ian Campbell , 810379@bugs.debian.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org --mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Feb 03, 2016 at 03:22:30PM +0100, Marek Marczykowski-G=F3recki wr= ote: > On Mon, Feb 01, 2016 at 09:50:53AM -0500, Konrad Rzeszutek Wilk wrote: > > > The second bullet looks at first pretty interesting from this PoV, > > > see=A0http://xenbits.xen.org/xsa/advisory-157.html=A0for info on th= e XSA and > > > the various patches. Konrad is on the CC already so hopefully he ha= s some > > > ideas. > >=20 > > Thanks. I will try to reproduce this with the upstream kernel first a= s > > those patches are there. >=20 > According to one Qubes OS user report[1], the bug was introduced betwee= n > version, which differs only by XSA-155 patches (including one for > pciback), especially not XSA-157.=20 > Maybe on some code path, some value is not copied back to pdev->sh_info= ->op? I found two bugs (attached the draft not-compiled patches). Upstream wise I seem to be tripping over another issue. There is also some more work required in there to fix the MSI-x enable op= . --mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="0001-xen-pciback-Check-PF-instead-of-VF-for-PCI_COMMAND_M.patch" >>From 34c754a209747826336f6e1f0477a55d214fcc28 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Wed, 3 Feb 2016 10:18:18 -0500 Subject: [PATCH 1/2] xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY c/s 408fb0e5aa7fda0059db282ff58c3b2a4278baa0 "xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set." would check the device for PCI_COMMAND_MEMORY which is great. Except that VF devices are unique - for example they have no legacy interrupts, and also any writes to PCI_COMMAND_MEMORY are silently ignored (by the hardware). CC: stable@vger.kernel.org Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/xen-pciback/pciback_ops.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c index 73dafdc..8c86a53 100644 --- a/drivers/xen/xen-pciback/pciback_ops.c +++ b/drivers/xen/xen-pciback/pciback_ops.c @@ -213,6 +213,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev, int i, result; struct msix_entry *entries; u16 cmd; + struct pci_dev *phys_dev; if (unlikely(verbose_request)) printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n", @@ -227,8 +228,10 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev, /* * PCI_COMMAND_MEMORY must be enabled, otherwise we may not be able * to access the BARs where the MSI-X entries reside. + * But VF devices are unique in which the PF needs to be checked. */ - pci_read_config_word(dev, PCI_COMMAND, &cmd); + phys_dev = pci_physfn(dev); + pci_read_config_word(phys_dev, PCI_COMMAND, &cmd); if (dev->msi_enabled || !(cmd & PCI_COMMAND_MEMORY)) return -ENXIO; -- 2.1.0 --mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="0002-xen-pciback-Save-the-number-of-MSI-X-entries-to-be-c.patch" >>From 0d83766e257e3bfb5ecd7483e2263ef89a986f4a Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Wed, 3 Feb 2016 10:22:02 -0500 Subject: [PATCH 2/2] xen/pciback: Save the number of MSI-X entries to be copied later. c/s 8135cf8b092723dbfcc611fe6fdcb3a36c9951c5 "xen/pciback: Save xen_pci_op commands before processing it" would copyback the processed values - which was great. However it missed the case that xen_pcibk_enable_msix - when completing would overwrite op->value (which had the number of MSI-X vectors requested) with the return value (which for success was zero). Hence the copy-back routine (which would use op->value) would copy exactly zero MSI-X vectors back. Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/xen-pciback/pciback_ops.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c index 8c86a53..2fc5880 100644 --- a/drivers/xen/xen-pciback/pciback_ops.c +++ b/drivers/xen/xen-pciback/pciback_ops.c @@ -335,7 +335,9 @@ void xen_pcibk_do_op(struct work_struct *data) struct xen_pcibk_dev_data *dev_data = NULL; struct xen_pci_op *op = &pdev->op; int test_intx = 0; - +#ifdef CONFIG_PCI_MSI + unsigned int nr = 0; +#endif *op = pdev->sh_info->op; barrier(); dev = xen_pcibk_get_pci_dev(pdev, op->domain, op->bus, op->devfn); @@ -363,6 +365,7 @@ void xen_pcibk_do_op(struct work_struct *data) op->err = xen_pcibk_disable_msi(pdev, dev, op); break; case XEN_PCI_OP_enable_msix: + nr = op->value; op->err = xen_pcibk_enable_msix(pdev, dev, op); break; case XEN_PCI_OP_disable_msix: @@ -385,7 +388,7 @@ void xen_pcibk_do_op(struct work_struct *data) if (op->cmd == XEN_PCI_OP_enable_msix && op->err == 0) { unsigned int i; - for (i = 0; i < op->value; i++) + for (i = 0; i < nr; i++) pdev->sh_info->op.msix_entries[i].vector = op->msix_entries[i].vector; } -- 2.1.0 --mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --mP3DRpeJDSE+ciuQ--