1 files changed, 11 insertions, 3 deletions

diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index a918553ebc75..750c346ef50a 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -65,7 +65,6 @@ static __init struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
                                                         int end, u64 addr)
 {
         struct pci_mmcfg_region *new;
-        int num_buses;
         struct resource *res;
 
         if (addr == 0)
@@ -82,10 +81,9 @@ static __init struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
 
         list_add_sorted(new);
 
-        num_buses = end - start + 1;
         res = &new->res;
         res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
-        res->end = addr + PCI_MMCFG_BUS_OFFSET(num_buses) - 1;
+        res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
         res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
         snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
                  "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
@@ -608,6 +606,16 @@ static void __init __pci_mmcfg_init(int early)
         if (list_empty(&pci_mmcfg_list))
                 return;
 
+        if (pcibios_last_bus < 0) {
+                const struct pci_mmcfg_region *cfg;
+
+                list_for_each_entry(cfg, &pci_mmcfg_list, list) {
+                        if (cfg->segment)
+                                break;
+                        pcibios_last_bus = cfg->end_bus;
+                }
+        }
+
         if (pci_mmcfg_arch_init())
                 pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
         else {