[Xen-devel] [PATCH v3] PCI: Add guard to avoid mapping a invalid msix base address

[Yijing Wang <wangyijing@xxxxxxxxxx>]

Sometimes, a pci bridge device BAR was not assigned
properly. After we call pci_bus_assign_resources(), the
resource of the BAR would be reseted. So if we try to
enable msix for this device, it will map a invalid
resource as the msix base address, and a warning call trace
will report.

pci_bus_assign_resources()
        __pci_bus_assign_resources()
                pbus_assign_resources_sorted()
                        __assign_resources_sorted()
                                assign_requested_resources_sorted()
                                        pci_assign_resource() -->fail
                                        reset_resource()        
-->res->start/end/flags = 0

pcie_port_device_register()
        init_service_irqs()
                pcie_port_enable_msix()
                        ...
                                msix_capability_init()
                                        msix_map_region()
                                                phys_addr = 
pci_resource_start(dev, bir) + table_offset;
If BAR(index=bir) was not assign properly, pci_resource_start(dev, bir)
here would return 0, so phys_addr is a invalid physical
address of msix.

[   43.094087] ------------[ cut here ]------------
[   43.097418] WARNING: CPU: 1 PID: 1800 at arch/arm64/mm/ioremap.c:58 
__ioremap_caller+0xd4/0xe8()
...
[   43.121694] CPU: 1 PID: 1800 Comm: insmod Tainted: G           O  3.16.0 #5
[   43.127374] Call trace:
[   43.128522] [<ffffffc0000891d4>] dump_backtrace+0x0/0x130
[   43.132637] [<ffffffc000089314>] show_stack+0x10/0x1c
[   43.136402] [<ffffffc0004db040>] dump_stack+0x74/0x94
[   43.140166] [<ffffffc0000986f8>] warn_slowpath_common+0x8c/0xb4
[   43.144804] [<ffffffc0000987e4>] warn_slowpath_null+0x14/0x20
[   43.149266] [<ffffffc000095474>] __ioremap_caller+0xd0/0xe8
[   43.153555] [<ffffffc000095498>] __ioremap+0xc/0x18
[   43.157145] [<ffffffc0002cc62c>] pci_enable_msix+0x238/0x44c
[   43.161521] [<ffffffc0002cc874>] pci_enable_msix_range+0x34/0x80
[   43.166243] [<ffffffc0002c946c>] pcie_port_device_register+0x104/0x480
[   43.171491] [<ffffffc0002c99f8>] pcie_portdrv_probe+0x38/0xa0
[   43.175952] [<ffffffc0002bd6c8>] pci_device_probe+0x78/0xd4
[   43.180238] [<ffffffc00030e68c>] really_probe+0x6c/0x22c
[   43.184265] [<ffffffc00030e8a8>] __device_attach+0x5c/0x6c
[   43.188466] [<ffffffc00030cb68>] bus_for_each_drv+0x50/0x94
[   43.192755] [<ffffffc00030e5fc>] device_attach+0x9c/0xc0
[   43.196780] [<ffffffc0002b4c54>] pci_bus_add_device+0x38/0x80
[   43.201243] [<ffffffc0002b5064>] pci_bus_add_devices+0x4c/0xd4
[   43.205791] [<ffffffc000093d70>] pci_common_init+0x274/0x378
[   43.210170] [<ffffffbff18e4b8c>] $x+0xb8c/0xc88 [pcie]
[   43.214024] [<ffffffc00031013c>] platform_drv_probe+0x20/0x58
[   43.218483] [<ffffffc00030e6e4>] really_probe+0xc4/0x22c
[   43.222510] [<ffffffc00030e958>] __driver_attach+0xa0/0xa8
[   43.226708] [<ffffffc00030cab0>] bus_for_each_dev+0x54/0x98
[   43.231000] [<ffffffc00030e234>] driver_attach+0x1c/0x28
[   43.235024] [<ffffffc00030deb0>] bus_add_driver+0x14c/0x204
[   43.239309] [<ffffffc00030f038>] driver_register+0x64/0x130
[   43.243598] [<ffffffc000310110>] __platform_driver_register+0x5c/0x68
[   43.248757] [<ffffffc0003101b4>] platform_driver_probe+0x28/0xac
[   43.253485] [<ffffffbff18e4cb8>] pcie_init+0x30/0x3c [pcie]
[   43.258293] [<ffffffc0000815dc>] do_one_initcall+0x88/0x19c
[   43.262585] [<ffffffc0000f6b74>] load_module+0xc2c/0xf2c
[   43.266609] [<ffffffc0000f6fd0>] SyS_finit_module+0x78/0x88
[   43.270897] ---[ end trace ea5eb60837afb5aa ]---

Reported-by: Zhang Jukuo <zhangjukuo@xxxxxxxxxx>
Tested-by: Zhang Jukuo <zhangjukuo@xxxxxxxxxx>
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
---
 arch/x86/pci/xen.c |    4 ++++
 drivers/pci/msi.c  |    5 +++++
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index c489ef2..34fc418 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 fd60806..c3e7dfc 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;
 
-- 
1.7.1


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