Re: [PATCH] x86/pci: intel ioh need to subtract mmconf range

Yinghai Lu
2010-01-15T00:40:27Z

On 01/14/2010 03:49 PM, Bjorn Helgaas wrote:
> On Thursday 14 January 2010 04:38:08 pm Yinghai Lu wrote:
>> On 01/14/2010 03:09 PM, Bjorn Helgaas wrote:
>>> On Thursday 14 January 2010 03:46:35 pm Yinghai Lu wrote:
>>>>
>>>> Bjorn pointed out we need to remove mmconf range
>>>>
>>>> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
>>>>
>>>> ---
>>>> arch/x86/pci/intel_bus.c | 29 +++++++++++++++++++++++++++--
>>>> 1 file changed, 27 insertions(+), 2 deletions(-)
>>>>
>>>> Index: linux-2.6/arch/x86/pci/intel_bus.c
>>>> ===================================================================
>>>> --- linux-2.6.orig/arch/x86/pci/intel_bus.c
>>>> +++ linux-2.6/arch/x86/pci/intel_bus.c
>>>> @@ -46,6 +46,20 @@ static inline void print_ioh_resources(s
>>>>
>>>> #define RANGE_NUM 16
>>>>
>>>> +static void __devinit subtract_mmconf(struct range *range, int nr)
>>>> +{
>>>> +#ifdef CONFIG_PCI_MMCONFIG
>>>> + struct pci_mmcfg_region *cfg;
>>>> +
>>>> + if (list_empty(&pci_mmcfg_list))
>>>> + return;
>>>> +
>>>> + list_for_each_entry(cfg, &pci_mmcfg_list, list)
>>>> + subtract_range(range, nr, cfg->res.start,
>>>> + cfg->res.end + 1);
>>>> +#endif
>>>
>>> This can't be right, can it? Let's say the kernel was built with
>>> CONFIG_PCI_MMCONFIG turned off, or the user used "pci=nommconf",
>>> or the kernel decides not to use MMCONFIG for some other reason.
>>>
>>> In that case, the hardware may still be configured to support
>>> MMCONFIG, but the pci_mmcfg_list will be empty, so your code will
>>> leave the window alone. We might assign some of that MMCONFIG
>>> space to a device, but the hardware will route it to MMCONFIG,
>>> not to the device.
>>
>> so if there is mmconf specified, we just skip the whole function?
>
> No, I'm saying that intel-bus.c must ALWAYS remove the MMCONFIG region
> from the host bridge apertures, even if Linux isn't using MMCONFIG.
>
> That means intel-bus.c has to be smart enough to figure out on its
> own what the MMCONFIG area is. It can't depend on mmconfig-shared.c
> to do it, because mmconfig-shared.c might not be there.

that seems go too far away...

Subject: [PATCH -v2] x86/pci: intel ioh need to subtrac mmconf range

Bjorn pointed out we need to remove mmconf range

-v2: if mmconf is not there, get out early.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
arch/x86/pci/Makefile | 3 ++-
arch/x86/pci/intel_bus.c | 30 ++++++++++++++++++++++++++++--
2 files changed, 30 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/pci/intel_bus.c
===================================================================
--- linux-2.6.orig/arch/x86/pci/intel_bus.c
+++ linux-2.6/arch/x86/pci/intel_bus.c
@@ -46,6 +46,18 @@ static inline void print_ioh_resources(s

#define RANGE_NUM 16

+static void __devinit subtract_mmconf(struct range *range, int nr)
+{
+ struct pci_mmcfg_region *cfg;
+
+ if (list_empty(&pci_mmcfg_list))
+ return;
+
+ list_for_each_entry(cfg, &pci_mmcfg_list, list)
+ subtract_range(range, nr, cfg->res.start,
+ cfg->res.end + 1);
+}
+
static void __devinit pci_root_bus_res(struct pci_dev *dev)
{
u16 word;
@@ -58,6 +70,9 @@ static void __devinit pci_root_bus_res(s
struct range range[RANGE_NUM];
int i;

+ if (list_empty(&pci_mmcfg_list))
+ return;
+
/* some sys doesn't get mmconf enabled */
if (dev->cfg_size < 0x200)
return;
@@ -96,6 +111,7 @@ static void __devinit pci_root_bus_res(s

subtract_range(range, RANGE_NUM, vt_base, vt_end + 1);
}
+ subtract_mmconf(range, RANGE_NUM);
for (i = 0; i < RANGE_NUM; i++) {
if (!range[i].end)
continue;
@@ -112,8 +128,18 @@ static void __devinit pci_root_bus_res(s
mmioh_base |= ((u64)(dword & 0x7ffff)) << 32;
pci_read_config_dword(dev, IOH_LMMIOH_LIMITU, &dword);
mmioh_end |= ((u64)(dword & 0x7ffff)) << 32;
- update_res(info, cap_resource(mmioh_base), cap_resource(mmioh_end),
- IORESOURCE_MEM, 0);
+ memset(range, 0, sizeof(range));
+ add_range(range, RANGE_NUM, 0, mmioh_base, mmioh_end + 1);
+ /* mmconf could be above 4g */
+ subtract_mmconf(range, RANGE_NUM);
+ for (i = 0; i < RANGE_NUM; i++) {
+ if (!range[i].end)
+ continue;
+
+ update_res(info, cap_resource(range[i].start),
+ cap_resource(range[i].end - 1),
+ IORESOURCE_MEM, 0);
+ }

print_ioh_resources(info);
}
Index: linux-2.6/arch/x86/pci/Makefile
===================================================================
--- linux-2.6.orig/arch/x86/pci/Makefile
+++ linux-2.6/arch/x86/pci/Makefile
@@ -14,7 +14,8 @@ obj-$(CONFIG_X86_VISWS) += visws.o
obj-$(CONFIG_X86_NUMAQ) += numaq_32.o

obj-y += common.o early.o
-obj-y += amd_bus.o bus_numa.o intel_bus.o
+obj-y += amd_bus.o bus_numa.o
+obj-$(CONFIG_PCI_MMCONFIG) += intel_bus.o

ifeq ($(CONFIG_PCI_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG