Attachment 1273684 Details for Bug 1433831 – RHEL7 version of the patch

[patch] RHEL7 version of the patch

0001-xen-do-not-re-use-pirq-number-cached-in-pci-device-m.patch (text/plain), 3.56 KB, created by Vitaly Kuznetsov on 2017-04-24 18:03:44 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Vitaly Kuznetsov

Created: 2017-04-24 18:03:44 UTC

Size: 3.56 KB

patch

obsolete

>From 5a2fae0c8f6525cd252494428866dc33c8ff3c98 Mon Sep 17 00:00:00 2001
>From: Dan Streetman <ddstreet@ieee.org>
>Date: Fri, 13 Jan 2017 15:07:51 -0500
>Subject: [RHEL7.4 KERNEL PATCH] xen: do not re-use pirq number cached in pci
> device msi msg data
>
>Revert the main part of commit:
>af42b8d12f8a ("xen: fix MSI setup and teardown for PV on HVM guests")
>
>That commit introduced reading the pci device's msi message data to see
>if a pirq was previously configured for the device's msi/msix, and re-use
>that pirq.  At the time, that was the correct behavior.  However, a
>later change to Qemu caused it to call into the Xen hypervisor to unmap
>all pirqs for a pci device, when the pci device disables its MSI/MSIX
>vectors; specifically the Qemu commit:
>c976437c7dba9c7444fb41df45468968aaa326ad
>("qemu-xen: free all the pirqs for msi/msix when driver unload")
>
>Once Qemu added this pirq unmapping, it was no longer correct for the
>kernel to re-use the pirq number cached in the pci device msi message
>data.  All Qemu releases since 2.1.0 contain the patch that unmaps the
>pirqs when the pci device disables its MSI/MSIX vectors.
>
>This bug is causing failures to initialize multiple NVMe controllers
>under Xen, because the NVMe driver sets up a single MSIX vector for
>each controller (concurrently), and then after using that to talk to
>the controller for some configuration data, it disables the single MSIX
>vector and re-configures all the MSIX vectors it needs.  So the MSIX
>setup code tries to re-use the cached pirq from the first vector
>for each controller, but the hypervisor has already given away that
>pirq to another controller, and its initialization fails.
>
>This is discussed in more detail at:
>https://lists.xen.org/archives/html/xen-devel/2017-01/msg00447.html
>
>Fixes: af42b8d12f8a ("xen: fix MSI setup and teardown for PV on HVM guests")
>Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
>Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
>Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>(cherry picked from commit c74fd80f2f41d05f350bb478151021f88551afe8)
>
>Conflicts:
>	arch/x86/pci/xen.c (no 4892c9b4a in RHEL as we don't care about Dom0,
>                            s,__pci_write_msi_msg,__write_msi_msg, context)
>---
> arch/x86/pci/xen.c | 23 +++++++----------------
> 1 file changed, 7 insertions(+), 16 deletions(-)
>
>diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>index 68537b8..e7a3db4 100644
>--- a/arch/x86/pci/xen.c
>+++ b/arch/x86/pci/xen.c
>@@ -228,23 +228,14 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> 		return 1;
> 
> 	list_for_each_entry(msidesc, &dev->msi_list, list) {
>-		__read_msi_msg(msidesc, &msg);
>-		pirq = MSI_ADDR_EXT_DEST_ID(msg.address_hi) |
>-			((msg.address_lo >> MSI_ADDR_DEST_ID_SHIFT) & 0xff);
>-		if (msg.data != XEN_PIRQ_MSI_DATA ||
>-		    xen_irq_from_pirq(pirq) < 0) {
>-			pirq = xen_allocate_pirq_msi(dev, msidesc);
>-			if (pirq < 0) {
>-				irq = -ENODEV;
>-				goto error;
>-			}
>-			xen_msi_compose_msg(dev, pirq, &msg);
>-			__write_msi_msg(msidesc, &msg);
>-			dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
>-		} else {
>-			dev_dbg(&dev->dev,
>-				"xen: msi already bound to pirq=%d\n", pirq);
>+		pirq = xen_allocate_pirq_msi(dev, msidesc);
>+		if (pirq < 0) {
>+			irq = -ENODEV;
>+			goto error;
> 		}
>+		xen_msi_compose_msg(dev, pirq, &msg);
>+		__write_msi_msg(msidesc, &msg);
>+		dev_dbg(&dev->dev, "xen: msi bound to pirq=%d\n", pirq);
> 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
> 					       (type == PCI_CAP_ID_MSIX) ?
> 					       "msi-x" : "msi",
>-- 
>2.9.3
>

Actions: View | Diff

Attachments on bug 1433831: 1265908 | 1265909 | 1267439 | 1269062 | 1272366 | 1272391 | 1272630 | 1272695 | 1273561 | 1273684