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| author |   Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2015-04-03 11:08:22 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2015-12-18 10:48:19 -0500 |
| commit | 56441f3c8e5bd45aab10dd9f8c505dd4bec03b0d (patch) | |
| tree | 35418204ad4079065a973a5cf63b715ab63e6e92 | |
| parent | xen/pciback: Save xen_pci_op commands before processing it (diff) | |
| download | linux-dev-56441f3c8e5bd45aab10dd9f8c505dd4bec03b0d.tar.xz linux-dev-56441f3c8e5bd45aab10dd9f8c505dd4bec03b0d.zip | |
xen/pciback: Return error on XEN_PCI_OP_enable_msi when device has MSI or MSI-X enabled
The guest sequence of:
a) XEN_PCI_OP_enable_msi
b) XEN_PCI_OP_enable_msi
c) XEN_PCI_OP_disable_msi
results in hitting an BUG_ON condition in the msi.c code.
The MSI code uses an dev->msi_list to which it adds MSI entries.
Under the above conditions an BUG_ON() can be hit. The device
passed in the guest MUST have MSI capability.
The a) adds the entry to the dev->msi_list and sets msi_enabled.
The b) adds a second entry but adding in to SysFS fails (duplicate entry)
and deletes all of the entries from msi_list and returns (with msi_enabled
is still set). c) pci_disable_msi passes the msi_enabled checks and hits:
BUG_ON(list_empty(dev_to_msi_list(&dev->dev)));
and blows up.
The patch adds a simple check in the XEN_PCI_OP_enable_msi to guard
against that. The check for msix_enabled is not stricly neccessary.
This is part of XSA-157.
CC: stable@vger.kernel.org
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| -rw-r--r-- | drivers/xen/xen-pciback/pciback_ops.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c index a0e0e3ed4905..8bfb87c1a9f3 100644 --- a/drivers/xen/xen-pciback/pciback_ops.c +++ b/drivers/xen/xen-pciback/pciback_ops.c @@ -144,7 +144,12 @@ int xen_pcibk_enable_msi(struct xen_pcibk_device *pdev, if (unlikely(verbose_request)) printk(KERN_DEBUG DRV_NAME ": %s: enable MSI\n", pci_name(dev)); - status = pci_enable_msi(dev); + if (dev->msi_enabled) + status = -EALREADY; + else if (dev->msix_enabled) + status = -ENXIO; + else + status = pci_enable_msi(dev); if (status) { pr_warn_ratelimited("%s: error enabling MSI for guest %u: err %d\n", |