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Commit 6a878e50 authored by Yijing Wang's avatar Yijing Wang Committed by Bjorn Helgaas
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PCI: Fail MSI-X mappings if there's no space assigned to MSI-X BAR 



Unlike MSI, which is configured via registers in the MSI capability in
Configuration Space, MSI-X is configured via tables in Memory Space.
These MSI-X tables are mapped by a device BAR, and if no Memory Space
has been assigned to the BAR, MSI-X cannot be used.

Fail MSI-X setup if no space has been assigned for the BAR.

Previously, we ioremapped the MSI-X table even if the resource hadn't been
assigned.  In this case, the resource address is undefined (and is often
zero), which may lead to warnings or oopses in this path:

  pci_enable_msix
    msix_capability_init
      msix_map_region
        ioremap_nocache

The PCI core sets resource flags to zero when it can't assign space for the
resource (see reset_resource()).  There are also some cases where it sets
the IORESOURCE_UNSET flag, e.g., pci_reassigndev_resource_alignment(),
pci_assign_resource(), etc.  So we must check for both cases.

[bhelgaas: changelog]
Reported-by: default avatarZhang Jukuo <zhangjukuo@huawei.com>
Tested-by: default avatarZhang Jukuo <zhangjukuo@huawei.com>
Signed-off-by: default avatarYijing Wang <wangyijing@huawei.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 97bf6af1

arch/x86/pci/xen.c

+4 −0
Original line number Diff line number Diff line
@@ -298,12 +298,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) 
			map_irq.entry_nr = nvec;

		} else if (type == PCI_CAP_ID_MSIX) {

			int pos;

			unsigned long flags;

			u32 table_offset, bir;



			pos = dev->msix_cap;

			pci_read_config_dword(dev, pos + PCI_MSIX_TABLE,

					      &table_offset);

			bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);

			flags = pci_resource_flags(dev, bir);

			if (!flags || (flags & IORESOURCE_UNSET))

				return -EINVAL;



			map_irq.table_base = pci_resource_start(dev, bir);

			map_irq.entry_nr = msidesc->msi_attrib.entry_nr;

drivers/pci/msi.c

+5 −0
Original line number Diff line number Diff line
@@ -694,11 +694,16 @@ static void __iomem *msix_map_region(struct pci_dev *dev, unsigned nr_entries) 
{

	resource_size_t phys_addr;

	u32 table_offset;

	unsigned long flags;

	u8 bir;



	pci_read_config_dword(dev, dev->msix_cap + PCI_MSIX_TABLE,

			      &table_offset);

	bir = (u8)(table_offset & PCI_MSIX_TABLE_BIR);

	flags = pci_resource_flags(dev, bir);

	if (!flags || (flags & IORESOURCE_UNSET))

		return NULL;



	table_offset &= PCI_MSIX_TABLE_OFFSET;

	phys_addr = pci_resource_start(dev, bir) + table_offset;