x86/PCI/ACPI: Make all resources except [io 0xcf8-0xcff] available on PCI bus
An IO port or MMIO resource assigned to a PCI host bridge may be
consumed by the host bridge itself or available to its child
bus/devices. The ACPI specification defines a bit (Producer/Consumer)
to tell whether the resource is consumed by the host bridge itself,
but firmware hasn't used that bit consistently, so we can't rely on it.
Before commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource
interfaces to simplify implementation"), arch/x86/pci/acpi.c ignored
all IO port resources defined by acpi_resource_io and
acpi_resource_fixed_io to filter out IO ports consumed by the host
bridge itself.
Commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource interfaces
to simplify implementation") started accepting all IO port and MMIO
resources, which caused a regression that IO port resources consumed
by the host bridge itself became available to its child devices.
Then commit 63f1789ec716 ("x86/PCI/ACPI: Ignore resources consumed by
host bridge itself") ignored resources consumed by the host bridge
itself by checking the IORESOURCE_WINDOW flag, which accidently removed
MMIO resources defined by acpi_resource_memory24, acpi_resource_memory32
and acpi_resource_fixed_memory32.
On x86 and IA64 platforms, all IO port and MMIO resources are assumed
to be available to child bus/devices except one special case:
IO port [0xCF8-0xCFF] is consumed by the host bridge itself
to access PCI configuration space.
So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF]. This solution
will also ease the way to consolidate ACPI PCI host bridge common code
from x86, ia64 and ARM64.
Related ACPI table are archived at:
https://bugzilla.kernel.org/show_bug.cgi?id=94221
Related discussions at:
http://patchwork.ozlabs.org/patch/461633/
https://lkml.org/lkml/2015/3/29/304
Fixes: 63f1789ec716 (Ignore resources consumed by host bridge itself)
Reported-by: Bernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index e469598..d939633 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -325,6 +325,26 @@
kfree(info);
}
+/*
+ * An IO port or MMIO resource assigned to a PCI host bridge may be
+ * consumed by the host bridge itself or available to its child
+ * bus/devices. The ACPI specification defines a bit (Producer/Consumer)
+ * to tell whether the resource is consumed by the host bridge itself,
+ * but firmware hasn't used that bit consistently, so we can't rely on it.
+ *
+ * On x86 and IA64 platforms, all IO port and MMIO resources are assumed
+ * to be available to child bus/devices except one special case:
+ * IO port [0xCF8-0xCFF] is consumed by the host bridge itself
+ * to access PCI configuration space.
+ *
+ * So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF].
+ */
+static bool resource_is_pcicfg_ioport(struct resource *res)
+{
+ return (res->flags & IORESOURCE_IO) &&
+ res->start == 0xCF8 && res->end == 0xCFF;
+}
+
static void probe_pci_root_info(struct pci_root_info *info,
struct acpi_device *device,
int busnum, int domain,
@@ -346,8 +366,8 @@
"no IO and memory resources present in _CRS\n");
else
resource_list_for_each_entry_safe(entry, tmp, list) {
- if ((entry->res->flags & IORESOURCE_WINDOW) == 0 ||
- (entry->res->flags & IORESOURCE_DISABLED))
+ if ((entry->res->flags & IORESOURCE_DISABLED) ||
+ resource_is_pcicfg_ioport(entry->res))
resource_list_destroy_entry(entry);
else
entry->res->name = info->name;