Re: [PATCH] [9/50] i386: validate against ACPI motherboard resources

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On 9/21/07, Andi Kleen <ak@suse.de> wrote:
>
> From: Robert Hancock <hancockr@shaw.ca>
>
> This path adds validation of the MMCONFIG table against the ACPI reserved
> motherboard resources.  If the MMCONFIG table is found to be reserved in
> ACPI, we don't bother checking the E820 table.  The PCI Express firmware
> spec apparently tells BIOS developers that reservation in ACPI is required
> and E820 reservation is optional, so checking against ACPI first makes
> sense.  Many BIOSes don't reserve the MMCONFIG region in E820 even though
> it is perfectly functional, the existing check needlessly disables MMCONFIG
> in these cases.
>
> In order to do this, MMCONFIG setup has been split into two phases.  If PCI
> configuration type 1 is not available then MMCONFIG is enabled early as
> before.  Otherwise, it is enabled later after the ACPI interpreter is
> enabled, since we need to be able to execute control methods in order to
> check the ACPI reserved resources.  Presently this is just triggered off
> the end of ACPI interpreter initialization.
>
> There are a few other behavioral changes here:
>
> - Validate all MMCONFIG configurations provided, not just the first one.
>
> - Validate the entire required length of each configuration according to
>   the provided ending bus number is reserved, not just the minimum required
>   allocation.
>
> - Validate that the area is reserved even if we read it from the chipset
>   directly and not from the MCFG table.  This catches the case where the
>   BIOS didn't set the location properly in the chipset and has mapped it
>   over other things it shouldn't have.
>
> This also cleans up the MMCONFIG initialization functions so that they
> simply do nothing if MMCONFIG is not compiled in.
>
> Based on an original patch by Rajesh Shah from Intel.
>
> [akpm@linux-foundation.org: many fixes and cleanups]
> Signed-off-by: Robert Hancock <hancockr@shaw.ca>
> Signed-off-by: Andi Kleen <ak@suse.de>
> Cc: Rajesh Shah <rajesh.shah@intel.com>
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Andi Kleen <ak@suse.de>
> Cc: Greg KH <greg@kroah.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>  arch/i386/pci/init.c            |    4 -
>  arch/i386/pci/mmconfig-shared.c |  151 +++++++++++++++++++++++++++++++++++-----
>  arch/i386/pci/pci.h             |    1
>  drivers/acpi/bus.c              |    2
>  include/linux/pci.h             |    8 ++
>  5 files changed, 144 insertions(+), 22 deletions(-)
>
> Index: linux/arch/i386/pci/init.c
> ===================================================================
> --- linux.orig/arch/i386/pci/init.c
> +++ linux/arch/i386/pci/init.c
> @@ -11,9 +11,7 @@ static __init int pci_access_init(void)
>  #ifdef CONFIG_PCI_DIRECT
>         type = pci_direct_probe();
>  #endif
> -#ifdef CONFIG_PCI_MMCONFIG
> -       pci_mmcfg_init(type);
> -#endif
> +       pci_mmcfg_early_init(type);
>         if (raw_pci_ops)
>                 return 0;
>  #ifdef CONFIG_PCI_BIOS
> Index: linux/arch/i386/pci/mmconfig-shared.c
> ===================================================================
> --- linux.orig/arch/i386/pci/mmconfig-shared.c
> +++ linux/arch/i386/pci/mmconfig-shared.c
> @@ -206,9 +206,78 @@ static void __init pci_mmcfg_insert_reso
>         pci_mmcfg_resources_inserted = 1;
>  }
>
> -static void __init pci_mmcfg_reject_broken(int type)
> +static acpi_status __init check_mcfg_resource(struct acpi_resource *res,
> +                                             void *data)
> +{
> +       struct resource *mcfg_res = data;
> +       struct acpi_resource_address64 address;
> +       acpi_status status;
> +
> +       if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
> +               struct acpi_resource_fixed_memory32 *fixmem32 =
> +                       &res->data.fixed_memory32;
> +               if (!fixmem32)
> +                       return AE_OK;
> +               if ((mcfg_res->start >= fixmem32->address) &&
> +                   (mcfg_res->end < (fixmem32->address +
> +                                     fixmem32->address_length))) {
> +                       mcfg_res->flags = 1;
> +                       return AE_CTRL_TERMINATE;
> +               }
> +       }
> +       if ((res->type != ACPI_RESOURCE_TYPE_ADDRESS32) &&
> +           (res->type != ACPI_RESOURCE_TYPE_ADDRESS64))
> +               return AE_OK;
> +
> +       status = acpi_resource_to_address64(res, &address);
> +       if (ACPI_FAILURE(status) ||
> +          (address.address_length <= 0) ||
> +          (address.resource_type != ACPI_MEMORY_RANGE))
> +               return AE_OK;
> +
> +       if ((mcfg_res->start >= address.minimum) &&
> +           (mcfg_res->end < (address.minimum + address.address_length))) {
> +               mcfg_res->flags = 1;
> +               return AE_CTRL_TERMINATE;
> +       }
> +       return AE_OK;
> +}
> +
> +static acpi_status __init find_mboard_resource(acpi_handle handle, u32 lvl,
> +               void *context, void **rv)
> +{
> +       struct resource *mcfg_res = context;
> +
> +       acpi_walk_resources(handle, METHOD_NAME__CRS,
> +                           check_mcfg_resource, context);
> +
> +       if (mcfg_res->flags)
> +               return AE_CTRL_TERMINATE;
> +
> +       return AE_OK;
> +}
> +
> +static int __init is_acpi_reserved(unsigned long start, unsigned long end)
> +{
> +       struct resource mcfg_res;
> +
> +       mcfg_res.start = start;
> +       mcfg_res.end = end;
> +       mcfg_res.flags = 0;
> +
> +       acpi_get_devices("PNP0C01", find_mboard_resource, &mcfg_res, NULL);
> +
> +       if (!mcfg_res.flags)
> +               acpi_get_devices("PNP0C02", find_mboard_resource, &mcfg_res,
> +                                NULL);
> +
> +       return mcfg_res.flags;
> +}
> +
> +static void __init pci_mmcfg_reject_broken(void)
>  {
>         typeof(pci_mmcfg_config[0]) *cfg;
> +       int i;
>
>         if ((pci_mmcfg_config_num == 0) ||
>             (pci_mmcfg_config == NULL) ||
> @@ -229,17 +298,37 @@ static void __init pci_mmcfg_reject_brok
>                 goto reject;
>         }
>
> -       /*
> -        * Only do this check when type 1 works. If it doesn't work
> -        * assume we run on a Mac and always use MCFG
> -        */
> -       if (type == 1 && !e820_all_mapped(cfg->address,
> -                                         cfg->address + MMCONFIG_APER_MIN,
> -                                         E820_RESERVED)) {
> -               printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %Lx is not"
> -                      " E820-reserved\n", cfg->address);
> -               goto reject;
> +       for (i = 0; i < pci_mmcfg_config_num; i++) {
> +               u32 size = (cfg->end_bus_number + 1) << 20;
> +               cfg = &pci_mmcfg_config[i];
> +               printk(KERN_NOTICE "PCI: MCFG configuration %d: base %lu "
> +                      "segment %hu buses %u - %u\n",
> +                      i, (unsigned long)cfg->address, cfg->pci_segment,
> +                      (unsigned int)cfg->start_bus_number,
> +                      (unsigned int)cfg->end_bus_number);
> +               if (is_acpi_reserved(cfg->address, cfg->address + size - 1)) {
> +                       printk(KERN_NOTICE "PCI: MCFG area at %Lx reserved "
> +                              "in ACPI motherboard resources\n",
> +                              cfg->address);
> +               } else {
> +                       printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %Lx is not"
> +                              " reserved in ACPI motherboard resources\n",
> +                              cfg->address);
> +                       /* Don't try to do this check unless configuration
> +                          type 1 is available. */
> +                       if ((pci_probe & PCI_PROBE_CONF1) &&
> +                           e820_all_mapped(cfg->address,
> +                                           cfg->address + size - 1,
> +                                           E820_RESERVED))
> +                               printk(KERN_NOTICE
> +                                      "PCI: MCFG area at %Lx reserved in "
> +                                       "E820\n",
> +                                      cfg->address);
> +                       else
> +                               goto reject;
> +               }
>         }
> +
>         return;
>
>  reject:
> @@ -249,20 +338,46 @@ reject:
>         pci_mmcfg_config_num = 0;
>  }
>
> -void __init pci_mmcfg_init(int type)
> +void __init pci_mmcfg_early_init(int type)
> +{
> +       if ((pci_probe & PCI_PROBE_MMCONF) == 0)
> +               return;
> +
> +       /* If type 1 access is available, no need to enable MMCONFIG yet, we can
> +          defer until later when the ACPI interpreter is available to better
> +          validate things. */
> +       if (type == 1)
> +               return;
> +
> +       acpi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
> +
> +       if ((pci_mmcfg_config_num == 0) ||
> +           (pci_mmcfg_config == NULL) ||
> +           (pci_mmcfg_config[0].address == 0))
> +               return;
> +
> +       if (pci_mmcfg_arch_init())
> +               pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
> +}
> +
> +void __init pci_mmcfg_late_init(void)
>  {
>         int known_bridge = 0;
>
> +       /* MMCONFIG disabled */
>         if ((pci_probe & PCI_PROBE_MMCONF) == 0)
>                 return;
>
> -       if (type == 1 && pci_mmcfg_check_hostbridge())
> -               known_bridge = 1;
> +       /* MMCONFIG already enabled */
> +       if (!(pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF))
> +               return;
>
> -       if (!known_bridge) {
> +       if ((pci_probe & PCI_PROBE_CONF1) && pci_mmcfg_check_hostbridge())
> +               known_bridge = 1;
> +       else
>                 acpi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
> -               pci_mmcfg_reject_broken(type);
> -       }
> +
> +       pci_mmcfg_reject_broken();
>
>         if ((pci_mmcfg_config_num == 0) ||
>             (pci_mmcfg_config == NULL) ||
> @@ -270,7 +385,7 @@ void __init pci_mmcfg_init(int type)
>                 return;
>
>         if (pci_mmcfg_arch_init()) {
> -               if (type == 1)
> +               if (pci_probe & PCI_PROBE_CONF1)
>                         unreachable_devices();
>                 if (known_bridge)
>                         pci_mmcfg_insert_resources(IORESOURCE_BUSY);
> Index: linux/arch/i386/pci/pci.h
> ===================================================================
> --- linux.orig/arch/i386/pci/pci.h
> +++ linux/arch/i386/pci/pci.h
> @@ -91,7 +91,6 @@ extern int pci_conf1_read(unsigned int s
>  extern int pci_direct_probe(void);
>  extern void pci_direct_init(int type);
>  extern void pci_pcbios_init(void);
> -extern void pci_mmcfg_init(int type);
>  extern void pcibios_sort(void);
>
>  /* pci-mmconfig.c */
> Index: linux/drivers/acpi/bus.c
> ===================================================================
> --- linux.orig/drivers/acpi/bus.c
> +++ linux/drivers/acpi/bus.c
> @@ -35,6 +35,7 @@
>  #ifdef CONFIG_X86
>  #include <asm/mpspec.h>
>  #endif
> +#include <linux/pci.h>
>  #include <acpi/acpi_bus.h>
>  #include <acpi/acpi_drivers.h>
>
> @@ -757,6 +758,7 @@ static int __init acpi_init(void)
>         result = acpi_bus_init();
>
>         if (!result) {
> +               pci_mmcfg_late_init();

No!

MMCONFIG will not work with acpi=off any more.

because acpi_init==>pci_mmcfg_late_init==>pci_mmcfg_check_hostbridge...

can you move pci_mmcfg_later_init out of acpi_init and just call
somewhere after acpi_init...
or put pci_mmcfg_check_hostbridge back to pci_mmcfg_early_init?

YH