Re: [Qemu-devel] [PATCH V7 23/24] apci: fix PXB behaviour if used with unsupported BIOS

[Marcel Apfelbaum]

On 05/31/2015 09:12 PM, Michael S. Tsirkin wrote:

On Mon, May 25, 2015 at 06:34:01PM +0300, Marcel Apfelbaum wrote:

PXB does not work with unsupported bioses, but should
not interfere with normal OS operation.
We don't ship them anymore, but it's reasonable
to keep the work-around until we update the bios in qemu.

We already did, did we not?

Yes, we did, but Gerd preferred to keep this patch around.
Adding him to thread.

CC: Gerd Hoffmann <kra...@redhat.com>

Thanks,
Marcel

Fix this by not adding PXB mem/IO chunks to _CRS
if they weren't configured by BIOS.

Signed-off-by: Marcel Apfelbaum <mar...@redhat.com>
---
  hw/i386/acpi-build.c | 87 ++++++++++++++++++++++++++++++++++------------------
  1 file changed, 58 insertions(+), 29 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index f7d2c80..895d64c 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -784,6 +784,14 @@ static Aml *build_crs(PCIHostState *host,
              range_base = r->addr;
              range_limit = r->addr + r->size - 1;

+            /*
+             * Work-around for old bioses
+             * that do not support multiple root buses
+             */
+            if (!range_base || range_base > range_limit) {
+                continue;
+            }
+
              if (r->type & PCI_BASE_ADDRESS_SPACE_IO) {
                  aml_append(crs,
                      aml_word_io(aml_min_fixed, aml_max_fixed,
@@ -817,45 +825,66 @@ static Aml *build_crs(PCIHostState *host,

              range_base = pci_bridge_get_base(dev, PCI_BASE_ADDRESS_SPACE_IO);
              range_limit = pci_bridge_get_limit(dev, 
PCI_BASE_ADDRESS_SPACE_IO);
-            aml_append(crs,
-                aml_word_io(aml_min_fixed, aml_max_fixed,
-                            aml_pos_decode, aml_entire_range,
-                            0,
-                            range_base,
-                            range_limit,
-                            0,
-                            range_limit - range_base + 1));
-            crs_range_insert(io_ranges, range_base, range_limit);
+
+            /*
+             * Work-around for old bioses
+             * that do not support multiple root buses
+             */
+            if (range_base || range_base > range_limit) {
+                aml_append(crs,
+                           aml_word_io(aml_min_fixed, aml_max_fixed,
+                                       aml_pos_decode, aml_entire_range,
+                                       0,
+                                       range_base,
+                                       range_limit,
+                                       0,
+                                       range_limit - range_base + 1));
+                crs_range_insert(io_ranges, range_base, range_limit);
+            }

              range_base =
                  pci_bridge_get_base(dev, PCI_BASE_ADDRESS_SPACE_MEMORY);
              range_limit =
                  pci_bridge_get_limit(dev, PCI_BASE_ADDRESS_SPACE_MEMORY);
-            aml_append(crs,
-                aml_dword_memory(aml_pos_decode, aml_min_fixed,
-                                 aml_max_fixed, aml_non_cacheable,
-                                 aml_ReadWrite,
-                                 0,
-                                 range_base,
-                                 range_limit,
-                                 0,
-                                 range_limit - range_base + 1));
-            crs_range_insert(mem_ranges, range_base, range_limit);
+
+            /*
+             * Work-around for old bioses
+             * that do not support multiple root buses
+             */
+            if (range_base || range_base > range_limit) {
+                aml_append(crs,
+                           aml_dword_memory(aml_pos_decode, aml_min_fixed,
+                                            aml_max_fixed, aml_non_cacheable,
+                                            aml_ReadWrite,
+                                            0,
+                                            range_base,
+                                            range_limit,
+                                            0,
+                                            range_limit - range_base + 1));
+                crs_range_insert(mem_ranges, range_base, range_limit);
+          }

              range_base =
                  pci_bridge_get_base(dev, PCI_BASE_ADDRESS_MEM_PREFETCH);
              range_limit =
                  pci_bridge_get_limit(dev, PCI_BASE_ADDRESS_MEM_PREFETCH);
-            aml_append(crs,
-                aml_dword_memory(aml_pos_decode, aml_min_fixed,
-                                 aml_max_fixed, aml_non_cacheable,
-                                 aml_ReadWrite,
-                                 0,
-                                 range_base,
-                                 range_limit,
-                                 0,
-                                 range_limit - range_base + 1));
-            crs_range_insert(mem_ranges, range_base, range_limit);
+
+            /*
+             * Work-around for old bioses
+             * that do not support multiple root buses
+             */
+            if (range_base || range_base > range_limit) {
+                aml_append(crs,
+                           aml_dword_memory(aml_pos_decode, aml_min_fixed,
+                                            aml_max_fixed, aml_non_cacheable,
+                                            aml_ReadWrite,
+                                            0,
+                                            range_base,
+                                            range_limit,
+                                            0,
+                                            range_limit - range_base + 1));
+                crs_range_insert(mem_ranges, range_base, range_limit);
+            }
          }
      }

--
2.1.0