[SeaBIOS] [PATCH 6/6] pci: runtime i/o window sizing

[Gerd Hoffmann]

Update the pci i/o windows at runtime, depending on the amount memory
the machine has.  The 32bit window starts above low memory and ends at
the ioapic map address, the 64bit window is placed above high memory.

Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 src/pciinit.c |   25 +++++++++++++++++++++----
 1 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/src/pciinit.c b/src/pciinit.c
index c1d932a..23706f7 100644
--- a/src/pciinit.c
+++ b/src/pciinit.c
@@ -591,6 +591,11 @@ static void pci_region_map_entries(struct pci_bus *busses, struct pci_region *r)
 
 static void pci_bios_map_devices(struct pci_bus *busses)
 {
+    u64 pcimem64_size;
+    int shift;
+
+    pcimem_start = RamSize;
+
     if (pci_bios_init_root_regions(busses)) {
         struct pci_region r64_mem, r64_pref;
         r64_mem.list = NULL;
@@ -603,14 +608,26 @@ static void pci_bios_map_devices(struct pci_bus *busses)
         if (pci_bios_init_root_regions(busses))
             panic("PCI: out of 32bit address space\n");
 
-        r64_mem.base = pcimem64_start;
-        u64 sum = pci_region_sum(&r64_mem);
-        u64 align = pci_region_align(&r64_pref);
-        r64_pref.base = ALIGN(r64_mem.base + sum, align);
+        // try 4 GB ... 512 GB
+        for (shift = 32; shift < 39; shift++) {
+            pcimem64_size = (1LL << shift);
+            pcimem64_start = (RamSizeOver4G + pcimem64_size) & ~(pcimem64_size-1);
+            pcimem64_end = pcimem64_start + pcimem64_size;
+
+            r64_mem.base = pcimem64_start;
+            u64 sum = pci_region_sum(&r64_mem);
+            u64 align = pci_region_align(&r64_pref);
+            r64_pref.base = ALIGN(r64_mem.base + sum, align);
+            if (r64_pref.base + pci_region_sum(&r64_pref) <= pcimem64_end)
+                break;
+        }
         if (r64_pref.base + pci_region_sum(&r64_pref) > pcimem64_end)
             panic("PCI: out of 64bit address space\n");
         pci_region_map_entries(busses, &r64_mem);
         pci_region_map_entries(busses, &r64_pref);
+    } else {
+        // no bars mapped high -> drop 64bit window (see dsdt)
+        pcimem64_start = 0;
     }
     // Map regions on each device.
     int bus;
-- 
1.7.1