> I applied this to pci/msi for v3.20, thanks! I reworked the changelog as
> follows; let me know if it still doesn't make things clear:
>
It's more clear, thanks for your improvement very much!
Thanks!
Yijing.
>
> commit 6a878e5085fe97bd1e222b7883a1b815fcbbe4ed
> Author: Yijing Wang <wangyijing@xxxxxxxxxx>
> Date: Wed Jan 28 09:52:17 2015 +0800
>
> 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: Zhang Jukuo <zhangjukuo@xxxxxxxxxx>
> Tested-by: Zhang Jukuo <zhangjukuo@xxxxxxxxxx>
> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index c489ef2c1a39..34fc4189ebf0 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -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;
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index fd60806d3fd0..c3e7dfcf9ff5 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -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;
>
>
> .
>
--
Thanks!
Yijing
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