1 files changed, 25 insertions, 4 deletions

diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c
index 5fbaa9132258..60f0e7a1162a 100644
--- a/arch/i386/pci/mmconfig.c
+++ b/arch/i386/pci/mmconfig.c
@@ -22,10 +22,31 @@ static u32 mmcfg_last_accessed_device;
 /*
  * Functions for accessing PCI configuration space with MMCONFIG accesses
  */
+static u32 get_base_addr(unsigned int seg, int bus)
+{
+        int cfg_num = -1;
+        struct acpi_table_mcfg_config *cfg;
+
+        while (1) {
+                ++cfg_num;
+                if (cfg_num >= pci_mmcfg_config_num) {
+                        /* something bad is going on, no cfg table is found. */
+                        /* so we fall back to the old way we used to do this */
+                        /* and just rely on the first entry to be correct. */
+                        return pci_mmcfg_config[0].base_address;
+                }
+                cfg = &pci_mmcfg_config[cfg_num];
+                if (cfg->pci_segment_group_number != seg)
+                        continue;
+                if ((cfg->start_bus_number <= bus) &&
+                    (cfg->end_bus_number >= bus))
+                        return cfg->base_address;
+        }
+}
 
-static inline void pci_exp_set_dev_base(int bus, int devfn)
+static inline void pci_exp_set_dev_base(unsigned int seg, int bus, int devfn)
 {
-        u32 dev_base = pci_mmcfg_config[0].base_address | (bus << 20) | (devfn << 12);
+        u32 dev_base = get_base_addr(seg, bus) | (bus << 20) | (devfn << 12);
         if (dev_base != mmcfg_last_accessed_device) {
                 mmcfg_last_accessed_device = dev_base;
                 set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
@@ -42,7 +63,7 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
 
         spin_lock_irqsave(&pci_config_lock, flags);
 
-        pci_exp_set_dev_base(bus, devfn);
+        pci_exp_set_dev_base(seg, bus, devfn);
 
         switch (len) {
         case 1:
@@ -71,7 +92,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
 
         spin_lock_irqsave(&pci_config_lock, flags);
 
-        pci_exp_set_dev_base(bus, devfn);
+        pci_exp_set_dev_base(seg, bus, devfn);
 
         switch (len) {
         case 1: