[PATCH 2] PNP: Work around BIOS defects in Intel MCH area reporting

[PATCH 2] PNP: Work around BIOS defects in Intel MCH area reporting

[Bjorn Helgaas]

Work around BIOSes that don't report the entire Intel MCH area.

MCHBAR is not an architected PCI BAR, so MCH space is usually reported as a
PNP0C02 resource.  The MCH space was once 16KB, but is 32KB in newer parts.
Some BIOSes still report a PNP0C02 resource that is only 16KB, which means
the rest of the MCH space is consumed but unreported.

This can cause resource map sanity check warnings or (theoretically) a
device conflict if we assigned the unreported space to another device.

The Intel perf event uncore driver tripped over this when it claimed the
MCH region:

  resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
  Info: mapping multiple BARs. Your kernel is fine.

To prevent this, if we find a PNP0C02 resource that covers part of the MCH
space, extend it to cover the entire space.

Link: http://lkml.kernel.org/r/20140224162400.GE16457@pd.tnic
Reported-by: Borislav Petkov <bp@alien8.de>
Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
---
 drivers/pnp/quirks.c |   75 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/drivers/pnp/quirks.c b/drivers/pnp/quirks.c
index 258fef272ea7..0d679068ef1b 100644
--- a/drivers/pnp/quirks.c
+++ b/drivers/pnp/quirks.c
@@ -15,6 +15,7 @@
 
 #include <linux/types.h>
 #include <linux/kernel.h>
+#include <linux/pci.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/pnp.h>
@@ -334,6 +335,79 @@ static void quirk_amd_mmconfig_area(struct pnp_dev *dev)
 }
 #endif
 
+/* Device IDs of parts that have 32KB MCH space */
+static const unsigned int mch_quirk_devices[] = {
+	0x0154,	/* Ivy Bridge */
+	0x0c00,	/* Haswell */
+};
+
+static struct pci_dev *get_intel_host(void)
+{
+	int i;
+	struct pci_dev *host;
+
+	for (i = 0; i < ARRAY_SIZE(mch_quirk_devices); i++) {
+		host = pci_get_device(PCI_VENDOR_ID_INTEL, mch_quirk_devices[i],
+				      NULL);
+		if (host)
+			return host;
+	}
+	return NULL;
+}
+
+static void quirk_intel_mch(struct pnp_dev *dev)
+{
+	struct pci_dev *host;
+	u32 addr_lo, addr_hi;
+	struct pci_bus_region region;
+	struct resource mch;
+	struct pnp_resource *pnp_res;
+	struct resource *res;
+
+	host = get_intel_host();
+	if (!host)
+		return;
+
+	/*
+	 * MCHBAR is not an architected PCI BAR, so MCH space is usually
+	 * reported as a PNP0C02 resource.  The MCH space was originally
+	 * 16KB, but is 32KB in newer parts.  Some BIOSes still report a
+	 * PNP0C02 resource that is only 16KB, which means the rest of the
+	 * MCH space is consumed but unreported.
+	 */
+
+	/*
+	 * Read MCHBAR for Host Member Mapped Register Range Base
+	 * https://www-ssl.intel.com/content/www/us/en/processors/core/4th-gen-core-family-desktop-vol-2-datasheet
+	 * Sec 3.1.12.
+	 */
+	pci_read_config_dword(host, 0x48, &addr_lo);
+	region.start = addr_lo & ~0x7fff;
+	pci_read_config_dword(host, 0x4c, &addr_hi);
+	region.start |= (u64) addr_hi << 32;
+	region.end = region.start + 32*1024 - 1;
+
+	memset(&mch, 0, sizeof(mch));
+	mch.flags = IORESOURCE_MEM;
+	pcibios_bus_to_resource(host->bus, &mch, &region);
+
+	list_for_each_entry(pnp_res, &dev->resources, list) {
+		res = &pnp_res->res;
+		if (res->end < mch.start || res->start > mch.end)
+			continue;	/* no overlap */
+		if (res->start == mch.start && res->end == mch.end)
+			continue;	/* exact match */
+
+		dev_info(&dev->dev, FW_BUG "PNP resource %pR covers only part of %s Intel MCH; extending to %pR\n",
+			 res, pci_name(host), &mch);
+		res->start = mch.start;
+		res->end = mch.end;
+		break;
+	}
+
+	pci_dev_put(host);
+}
+
 /*
  *  PnP Quirks
  *  Cards or devices that need some tweaking due to incomplete resource info
@@ -364,6 +438,7 @@ static struct pnp_fixup pnp_fixups[] = {
 #ifdef CONFIG_AMD_NB
 	{"PNP0c01", quirk_amd_mmconfig_area},
 #endif
+	{"PNP0c02", quirk_intel_mch},
 	{""}
 };
 

Re: [PATCH 2] PNP: Work around BIOS defects in Intel MCH area reporting

[Stephane Eranian]

On Tue, Apr 22, 2014 at 12:17 AM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> Work around BIOSes that don't report the entire Intel MCH area.
>
> MCHBAR is not an architected PCI BAR, so MCH space is usually reported as a
> PNP0C02 resource.  The MCH space was once 16KB, but is 32KB in newer parts.
> Some BIOSes still report a PNP0C02 resource that is only 16KB, which means
> the rest of the MCH space is consumed but unreported.
>
> This can cause resource map sanity check warnings or (theoretically) a
> device conflict if we assigned the unreported space to another device.
>
> The Intel perf event uncore driver tripped over this when it claimed the
> MCH region:
>
>   resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
>   Info: mapping multiple BARs. Your kernel is fine.
>
> To prevent this, if we find a PNP0C02 resource that covers part of the MCH
> space, extend it to cover the entire space.
>
Works for me on my Levono IvyBridge laptop.
Thanks for fixing this, Bjorn.
Acked-by: Stephane Eranian <eranian@google.com>

> Link: http://lkml.kernel.org/r/20140224162400.GE16457@pd.tnic
> Reported-by: Borislav Petkov <bp@alien8.de>
> Tested-by: Borislav Petkov <bp@suse.de>
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> Acked-by: Borislav Petkov <bp@suse.de>
> ---
>  drivers/pnp/quirks.c |   75 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 75 insertions(+)
>
> diff --git a/drivers/pnp/quirks.c b/drivers/pnp/quirks.c
> index 258fef272ea7..0d679068ef1b 100644
> --- a/drivers/pnp/quirks.c
> +++ b/drivers/pnp/quirks.c
> @@ -15,6 +15,7 @@
>
>  #include <linux/types.h>
>  #include <linux/kernel.h>
> +#include <linux/pci.h>
>  #include <linux/string.h>
>  #include <linux/slab.h>
>  #include <linux/pnp.h>
> @@ -334,6 +335,79 @@ static void quirk_amd_mmconfig_area(struct pnp_dev *dev)
>  }
>  #endif
>
> +/* Device IDs of parts that have 32KB MCH space */
> +static const unsigned int mch_quirk_devices[] = {
> +       0x0154, /* Ivy Bridge */
> +       0x0c00, /* Haswell */
> +};
> +
> +static struct pci_dev *get_intel_host(void)
> +{
> +       int i;
> +       struct pci_dev *host;
> +
> +       for (i = 0; i < ARRAY_SIZE(mch_quirk_devices); i++) {
> +               host = pci_get_device(PCI_VENDOR_ID_INTEL, mch_quirk_devices[i],
> +                                     NULL);
> +               if (host)
> +                       return host;
> +       }
> +       return NULL;
> +}
> +
> +static void quirk_intel_mch(struct pnp_dev *dev)
> +{
> +       struct pci_dev *host;
> +       u32 addr_lo, addr_hi;
> +       struct pci_bus_region region;
> +       struct resource mch;
> +       struct pnp_resource *pnp_res;
> +       struct resource *res;
> +
> +       host = get_intel_host();
> +       if (!host)
> +               return;
> +
> +       /*
> +        * MCHBAR is not an architected PCI BAR, so MCH space is usually
> +        * reported as a PNP0C02 resource.  The MCH space was originally
> +        * 16KB, but is 32KB in newer parts.  Some BIOSes still report a
> +        * PNP0C02 resource that is only 16KB, which means the rest of the
> +        * MCH space is consumed but unreported.
> +        */
> +
> +       /*
> +        * Read MCHBAR for Host Member Mapped Register Range Base
> +        * https://www-ssl.intel.com/content/www/us/en/processors/core/4th-gen-core-family-desktop-vol-2-datasheet
> +        * Sec 3.1.12.
> +        */
> +       pci_read_config_dword(host, 0x48, &addr_lo);
> +       region.start = addr_lo & ~0x7fff;
> +       pci_read_config_dword(host, 0x4c, &addr_hi);
> +       region.start |= (u64) addr_hi << 32;
> +       region.end = region.start + 32*1024 - 1;
> +
> +       memset(&mch, 0, sizeof(mch));
> +       mch.flags = IORESOURCE_MEM;
> +       pcibios_bus_to_resource(host->bus, &mch, &region);
> +
> +       list_for_each_entry(pnp_res, &dev->resources, list) {
> +               res = &pnp_res->res;
> +               if (res->end < mch.start || res->start > mch.end)
> +                       continue;       /* no overlap */
> +               if (res->start == mch.start && res->end == mch.end)
> +                       continue;       /* exact match */
> +
> +               dev_info(&dev->dev, FW_BUG "PNP resource %pR covers only part of %s Intel MCH; extending to %pR\n",
> +                        res, pci_name(host), &mch);
> +               res->start = mch.start;
> +               res->end = mch.end;
> +               break;
> +       }
> +
> +       pci_dev_put(host);
> +}
> +
>  /*
>   *  PnP Quirks
>   *  Cards or devices that need some tweaking due to incomplete resource info
> @@ -364,6 +438,7 @@ static struct pnp_fixup pnp_fixups[] = {
>  #ifdef CONFIG_AMD_NB
>         {"PNP0c01", quirk_amd_mmconfig_area},
>  #endif
> +       {"PNP0c02", quirk_intel_mch},
>         {""}
>  };
>
>

Re: [PATCH 2] PNP: Work around BIOS defects in Intel MCH area reporting

[Ingo Molnar]

* Stephane Eranian <eranian@google.com> wrote:

> On Tue, Apr 22, 2014 at 12:17 AM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> > Work around BIOSes that don't report the entire Intel MCH area.
> >
> > MCHBAR is not an architected PCI BAR, so MCH space is usually reported as a
> > PNP0C02 resource.  The MCH space was once 16KB, but is 32KB in newer parts.
> > Some BIOSes still report a PNP0C02 resource that is only 16KB, which means
> > the rest of the MCH space is consumed but unreported.
> >
> > This can cause resource map sanity check warnings or (theoretically) a
> > device conflict if we assigned the unreported space to another device.
> >
> > The Intel perf event uncore driver tripped over this when it claimed the
> > MCH region:
> >
> >   resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
> >   Info: mapping multiple BARs. Your kernel is fine.
> >
> > To prevent this, if we find a PNP0C02 resource that covers part of the MCH
> > space, extend it to cover the entire space.
> >
> Works for me on my Levono IvyBridge laptop.
> Thanks for fixing this, Bjorn.
> Acked-by: Stephane Eranian <eranian@google.com>

Just curious, what problems triggered on your laptop: only the 
warnings, or did something get mapped to the undeclared area,
causing other misbehavor?

Thanks,

	Ingo

Re: [PATCH 2] PNP: Work around BIOS defects in Intel MCH area reporting

[Stephane Eranian]

On Thu, Apr 24, 2014 at 9:20 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Stephane Eranian <eranian@google.com> wrote:
>
>> On Tue, Apr 22, 2014 at 12:17 AM, Bjorn Helgaas <bhelgaas@google.com> wrote:
>> > Work around BIOSes that don't report the entire Intel MCH area.
>> >
>> > MCHBAR is not an architected PCI BAR, so MCH space is usually reported as a
>> > PNP0C02 resource.  The MCH space was once 16KB, but is 32KB in newer parts.
>> > Some BIOSes still report a PNP0C02 resource that is only 16KB, which means
>> > the rest of the MCH space is consumed but unreported.
>> >
>> > This can cause resource map sanity check warnings or (theoretically) a
>> > device conflict if we assigned the unreported space to another device.
>> >
>> > The Intel perf event uncore driver tripped over this when it claimed the
>> > MCH region:
>> >
>> >   resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
>> >   Info: mapping multiple BARs. Your kernel is fine.
>> >
>> > To prevent this, if we find a PNP0C02 resource that covers part of the MCH
>> > space, extend it to cover the entire space.
>> >
>> Works for me on my Levono IvyBridge laptop.
>> Thanks for fixing this, Bjorn.
>> Acked-by: Stephane Eranian <eranian@google.com>
>
> Just curious, what problems triggered on your laptop: only the
> warnings, or did something get mapped to the undeclared area,
> causing other misbehavor?
>
In my case, it was just the warning. Everything appeared to worked correctly.