From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
ACPI firmware advertises PCI host bridge resources via PNP0A03 _CRS
methods. Some BIOSes include non-window address space in _CRS, and if we
allocate that non-window space for PCI devices, they don't work.
4dc2287c1805 ("x86: avoid E820 regions when allocating address space")
works around this issue by clipping out any regions mentioned in the E820
table in the allocate_resource() path, but the implementation has several
issues:
- The clipping is done for *all* allocations, not just those for PCI
address space,
- The clipping is done at each allocation instead of being done once when
setting up the host bridge windows, and
- The host bridge windows logged in dmesg do not reflect the clipping,
and in fact there is *no* indication in dmesg, which complicates
debugging.
Rework the implementation so we only clip PCI host bridge windows, we do it
once when setting them up, we a log message when a window is clipped, and
we reflect the clip when printing the host bridge windows.
I intend this only to improve the logging, not to fix any issues.
Example output changes:
BIOS-e820: [mem 0x00000000b0000000-0x00000000c00fffff] reserved
+ acpi PNP0A08:00: clipped [mem 0xc0000000-0xfebfffff window] to [mem 0xc0100000-0xfebfffff window] for e820 entry [mem 0xb0000000-0xc00fffff]
- pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window]
+ pci_bus 0000:00: root bus resource [mem 0xc0100000-0xfebfffff window]
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
arch/x86/include/asm/e820/api.h | 5 +++++
arch/x86/kernel/resource.c | 17 ++++++++++++-----
arch/x86/pci/acpi.c | 5 +++++
3 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index e8f58ddd06d9..5a39ed59b6db 100644
--- a/arch/x86/include/asm/e820/api.h
+++ b/arch/x86/include/asm/e820/api.h
@@ -4,6 +4,9 @@
#include <asm/e820/types.h>
+struct device;
+struct resource;
+
extern struct e820_table *e820_table;
extern struct e820_table *e820_table_kexec;
extern struct e820_table *e820_table_firmware;
@@ -43,6 +46,8 @@ extern void e820__register_nosave_regions(unsigned long limit_pfn);
extern int e820__get_entry_type(u64 start, u64 end);
+extern void remove_e820_regions(struct device *dev, struct resource *avail);
+
/*
* Returns true iff the specified range [start,end) is completely contained inside
* the ISA region.
diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c
index 8ffe68437744..7378ea146976 100644
--- a/arch/x86/kernel/resource.c
+++ b/arch/x86/kernel/resource.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
+#include <linux/dev_printk.h>
#include <linux/ioport.h>
#include <asm/e820/api.h>
@@ -23,18 +24,27 @@ static void resource_clip(struct resource *res, resource_size_t start,
res->start = end + 1;
}
-static void remove_e820_regions(struct resource *avail)
+void remove_e820_regions(struct device *dev, struct resource *avail)
{
+ struct resource orig = *avail;
int i;
struct e820_entry *entry;
u64 e820_start, e820_end;
+ if (!(avail->flags & IORESOURCE_MEM))
+ return;
+
for (i = 0; i < e820_table->nr_entries; i++) {
entry = &e820_table->entries[i];
e820_start = entry->addr;
e820_end = entry->addr + entry->size - 1;
resource_clip(avail, e820_start, e820_end);
+ if (orig.start != avail->start || orig.end != avail->end) {
+ dev_info(dev, "clipped %pR to %pR for e820 entry [mem %#010Lx-%#010Lx]\n",
+ &orig, avail, e820_start, e820_end);
+ orig = *avail;
+ }
}
}
@@ -45,9 +55,6 @@ void arch_remove_reservations(struct resource *avail)
* the low 1MB unconditionally, as this area is needed for some ISA
* cards requiring a memory range, e.g. the i82365 PCMCIA controller.
*/
- if (avail->flags & IORESOURCE_MEM) {
+ if (avail->flags & IORESOURCE_MEM)
resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
-
- remove_e820_regions(avail);
- }
}
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 052f1d78a562..562c81a51ea0 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -8,6 +8,7 @@
#include <linux/pci-acpi.h>
#include <asm/numa.h>
#include <asm/pci_x86.h>
+#include <asm/e820/api.h>
struct pci_root_info {
struct acpi_pci_root_info common;
@@ -299,6 +300,10 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
int status;
status = acpi_pci_probe_root_resources(ci);
+
+ resource_list_for_each_entry(entry, &ci->resources)
+ remove_e820_regions(&device->dev, entry->res);
+
if (pci_use_crs) {
resource_list_for_each_entry_safe(entry, tmp, &ci->resources)
if (resource_is_pcicfg_ioport(entry->res))
--
2.25.1
