limit address space used for pci devices.

For better compatibility with old linux kernels,
see source code comment.

Also rename some variables to make the code more
readable, following suggestions by Kevin.

Related (same problem in ovmf):
https://github.com/tianocore/edk2/commit/c1e853769046

Cc: Kevin O'Connor <kevin@koconnor.net>
Reported-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 26 insertions, 12 deletions

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index c7084f5e..6b13cd5b 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -46,12 +46,16 @@ static const char *region_type_name[] = {
     [ PCI_REGION_TYPE_PREFMEM ] = "prefmem",
 };
 
+// Memory ranges exported to legacy ACPI type table generation
 u64 pcimem_start   = BUILD_PCIMEM_START;
 u64 pcimem_end     = BUILD_PCIMEM_END;
 u64 pcimem64_start = BUILD_PCIMEM64_START;
 u64 pcimem64_end   = BUILD_PCIMEM64_END;
-u64 pci_io_low_end = 0xa000;
-u32 pci_use_64bit  = 0;
+
+// Resource allocation limits
+static u64 pci_io_low_end = 0xa000;
+static u64 pci_mem64_top  = 0;
+static u32 pci_pad_mem64  = 0;
 
 struct pci_region_entry {
     struct pci_device *dev;
@@ -966,8 +970,9 @@ static int pci_bios_check_devices(struct pci_bus *busses)
             int resource_optional = 0;
             if (hotplug_support == HOTPLUG_PCIE)
                 resource_optional = pcie_cap && (type == PCI_REGION_TYPE_IO);
-            if (hotplug_support && pci_use_64bit && is64 && (type == PCI_REGION_TYPE_PREFMEM))
-                align = (u64)1 << (CPUPhysBits - 11);
+            if (hotplug_support && pci_pad_mem64 && is64
+                && (type == PCI_REGION_TYPE_PREFMEM))
+                align = pci_mem64_top >> 11;
             if (align > sum && hotplug_support && !resource_optional)
                 sum = align; /* reserve min size for hot-plug */
             if (size > sum) {
@@ -1111,7 +1116,7 @@ static void pci_bios_map_devices(struct pci_bus *busses)
         panic("PCI: out of I/O address space\n");
 
     dprintf(1, "PCI: 32: %016llx - %016llx\n", pcimem_start, pcimem_end);
-    if (pci_use_64bit || pci_bios_init_root_regions_mem(busses)) {
+    if (pci_pad_mem64 || pci_bios_init_root_regions_mem(busses)) {
         struct pci_region r64_mem, r64_pref;
         r64_mem.list.first = NULL;
         r64_pref.list.first = NULL;
@@ -1131,14 +1136,13 @@ static void pci_bios_map_devices(struct pci_bus *busses)
         r64_mem.base = le64_to_cpu(romfile_loadint("etc/reserved-memory-end", 0));
         if (r64_mem.base < 0x100000000LL + RamSizeOver4G)
             r64_mem.base = 0x100000000LL + RamSizeOver4G;
-        if (CPUPhysBits) {
-            u64 top = 1LL << CPUPhysBits;
+        if (pci_mem64_top) {
             u64 size = (ALIGN(sum_mem, (1LL<<30)) +
                         ALIGN(sum_pref, (1LL<<30)));
-            if (pci_use_64bit)
-                size = ALIGN(size, (1LL<<(CPUPhysBits-3)));
-            if (r64_mem.base < top - size) {
-                r64_mem.base = top - size;
+            if (pci_pad_mem64)
+                size = ALIGN(size, pci_mem64_top >> 3);
+            if (r64_mem.base < pci_mem64_top - size) {
+                r64_mem.base = pci_mem64_top - size;
             }
             if (e820_is_used(r64_mem.base, size))
                 r64_mem.base -= size;
@@ -1181,8 +1185,18 @@ pci_setup(void)
 
     dprintf(3, "pci setup\n");
 
+    if (CPUPhysBits) {
+        pci_mem64_top = 1LL << CPUPhysBits;
+        if (CPUPhysBits > 46) {
+            // Old linux kernels have trouble dealing with more than 46
+            // phys-bits, so avoid that for now.  Seems to be a bug in the
+            // virtio-pci driver.  Reported: centos-7, ubuntu-18.04
+            pci_mem64_top = 1LL << 46;
+        }
+    }
+
     if (CPUPhysBits >= 36 && CPULongMode && RamSizeOver4G)
-        pci_use_64bit = 1;
+        pci_pad_mem64 = 1;
 
     dprintf(1, "=== PCI bus & bridge init ===\n");
     if (pci_probe_host() != 0) {