PCI: vmd: Fix config addressing when using bus offsets

VMD maps child device config spaces to the VMD Config BAR linearly
regardless of the starting bus offset. Because of this, the config
address decode must ignore starting bus offsets when mapping the BDF to
the config space address.

Fixes: 2a5a9c9a20f9 ("PCI: vmd: Add offset to bus numbers if necessary")
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org # v5.2+

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 4575e0c..2e4da3f 100644 (file)
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -94,6 +94,7 @@ struct vmd_dev {
        struct resource         resources[3];
        struct irq_domain       *irq_domain;
        struct pci_bus          *bus;
+       u8                      busn_start;
 
        struct dma_map_ops      dma_ops;
        struct dma_domain       dma_domain;
@@ -440,7 +441,8 @@ static char __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
                                  unsigned int devfn, int reg, int len)
 {
        char __iomem *addr = vmd->cfgbar +
-                            (bus->number << 20) + (devfn << 12) + reg;
+                            ((bus->number - vmd->busn_start) << 20) +
+                            (devfn << 12) + reg;
 
        if ((addr - vmd->cfgbar) + len >=
            resource_size(&vmd->dev->resource[VMD_CFGBAR]))
@@ -563,7 +565,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
        unsigned long flags;
        LIST_HEAD(resources);
        resource_size_t offset[2] = {0};
-       resource_size_t membar2_offset = 0x2000, busn_start = 0;
+       resource_size_t membar2_offset = 0x2000;
        struct pci_bus *child;
 
        /*
@@ -606,14 +608,14 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
                pci_read_config_dword(vmd->dev, PCI_REG_VMCONFIG, &vmconfig);
                if (BUS_RESTRICT_CAP(vmcap) &&
                    (BUS_RESTRICT_CFG(vmconfig) == 0x1))
-                       busn_start = 128;
+                       vmd->busn_start = 128;
        }
 
        res = &vmd->dev->resource[VMD_CFGBAR];
        vmd->resources[0] = (struct resource) {
                .name  = "VMD CFGBAR",
-               .start = busn_start,
-               .end   = busn_start + (resource_size(res) >> 20) - 1,
+               .start = vmd->busn_start,
+               .end   = vmd->busn_start + (resource_size(res) >> 20) - 1,
                .flags = IORESOURCE_BUS | IORESOURCE_PCI_FIXED,
        };
 
@@ -681,8 +683,8 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
        pci_add_resource_offset(&resources, &vmd->resources[1], offset[0]);
        pci_add_resource_offset(&resources, &vmd->resources[2], offset[1]);
 
-       vmd->bus = pci_create_root_bus(&vmd->dev->dev, busn_start, &vmd_ops,
-                                      sd, &resources);
+       vmd->bus = pci_create_root_bus(&vmd->dev->dev, vmd->busn_start,
+                                      &vmd_ops, sd, &resources);
        if (!vmd->bus) {
                pci_free_resource_list(&resources);
                irq_domain_remove(vmd->irq_domain);