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

["Michael S. Tsirkin" <mst@redhat.com>]

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?

> Fix this by not adding PXB mem/IO chunks to _CRS
> if they weren't configured by BIOS.
> 
> Signed-off-by: Marcel Apfelbaum <marcel@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
>