[PATCH v3 4/5] PCI: modify kernel parameters to differentiate between MMIO and MMIO_PREF sizes

From: Nicholas Johnson
Date: Mon Apr 15 2019 - 13:10:03 EST


Add kernel parameter pci=hpmemprefsize=nn[KMG] to control MMIO_PREF
size.

Change behaviour of pci=hpmemsize=nn[KMG] to only control MMIO size,
rather than controlling both MMIO and MMIO_PREF sizes.

Update kernel-parameters documentation to reflect the above changes.

Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx>
---
.../admin-guide/kernel-parameters.txt | 3 +++
drivers/pci/pci.c | 5 +++++
drivers/pci/setup-bus.c | 22 ++++++++++---------
include/linux/pci.h | 1 +
4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 858b6c0b9..908d01027 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3332,6 +3332,9 @@
hpmemsize=nn[KMG] The fixed amount of bus space which is
reserved for hotplug bridge's memory window.
Default size is 2 megabytes.
+ hpmemprefsize=nn[KMG] The fixed amount of bus space which is
+ reserved for hotplug bridge's MMIO_PREF window.
+ Default size is 2 megabytes.
hpbussize=nn The minimum amount of additional bus numbers
reserved for buses below a hotplug bridge.
Default is 1.
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c25acace7..c36c92118 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -86,9 +86,11 @@ unsigned long pci_cardbus_mem_size = DEFAULT_CARDBUS_MEM_SIZE;

#define DEFAULT_HOTPLUG_IO_SIZE (256)
#define DEFAULT_HOTPLUG_MEM_SIZE (2*1024*1024)
+#define DEFAULT_HOTPLUG_MEM_PREF_SIZE (2*1024*1024)
/* pci=hpmemsize=nnM,hpiosize=nn can override this */
unsigned long pci_hotplug_io_size = DEFAULT_HOTPLUG_IO_SIZE;
unsigned long pci_hotplug_mem_size = DEFAULT_HOTPLUG_MEM_SIZE;
+unsigned long pci_hotplug_mem_pref_size = DEFAULT_HOTPLUG_MEM_PREF_SIZE;

#define DEFAULT_HOTPLUG_BUS_SIZE 1
unsigned long pci_hotplug_bus_size = DEFAULT_HOTPLUG_BUS_SIZE;
@@ -6179,6 +6181,9 @@ static int __init pci_setup(char *str)
pci_hotplug_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "hpmemsize=", 10)) {
pci_hotplug_mem_size = memparse(str + 10, &str);
+ } else if (!strncmp(str, "hpmemprefsize=", 14)) {
+ pci_hotplug_mem_pref_size =
+ memparse(str + 14, &str);
} else if (!strncmp(str, "hpbussize=", 10)) {
pci_hotplug_bus_size =
simple_strtoul(str + 10, &str, 0);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index efe899b02..3806c9ff0 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1223,7 +1223,8 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
{
struct pci_dev *dev;
unsigned long mask, prefmask, type2 = 0, type3 = 0;
- resource_size_t additional_mem_size = 0, additional_io_size = 0;
+ resource_size_t additional_io_size = 0, additional_mem_size = 0,
+ additional_mem_pref_size = 0;
struct resource *b_res;
int ret;

@@ -1258,6 +1259,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
if (bus->self->is_hotplug_bridge) {
additional_io_size = pci_hotplug_io_size;
additional_mem_size = pci_hotplug_mem_size;
+ additional_mem_pref_size = pci_hotplug_mem_pref_size;
}
/* Fall through */
default:
@@ -1274,9 +1276,9 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
if (b_res[2].flags & IORESOURCE_MEM_64) {
prefmask |= IORESOURCE_MEM_64;
ret = pbus_size_mem(bus, prefmask, prefmask,
- prefmask, prefmask,
- realloc_head ? 0 : additional_mem_size,
- additional_mem_size, realloc_head);
+ prefmask, prefmask,
+ realloc_head ? 0 : additional_mem_pref_size,
+ additional_mem_pref_size, realloc_head);

/*
* If successful, all non-prefetchable resources and any
@@ -1298,9 +1300,9 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
if (!type2) {
prefmask &= ~IORESOURCE_MEM_64;
ret = pbus_size_mem(bus, prefmask, prefmask,
- prefmask, prefmask,
- realloc_head ? 0 : additional_mem_size,
- additional_mem_size, realloc_head);
+ prefmask, prefmask,
+ realloc_head ? 0 : additional_mem_pref_size,
+ additional_mem_pref_size, realloc_head);

/*
* If successful, only non-prefetchable resources
@@ -1309,7 +1311,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
if (ret == 0)
mask = prefmask;
else
- additional_mem_size += additional_mem_size;
+ additional_mem_size += additional_mem_pref_size;

type2 = type3 = IORESOURCE_MEM;
}
@@ -1329,8 +1331,8 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head)
* prefetchable resource in a 64-bit prefetchable window.
*/
pbus_size_mem(bus, mask, IORESOURCE_MEM, type2, type3,
- realloc_head ? 0 : additional_mem_size,
- additional_mem_size, realloc_head);
+ realloc_head ? 0 : additional_mem_size,
+ additional_mem_size, realloc_head);
break;
}
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 65f1d8c2f..a179856bf 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1960,6 +1960,7 @@ extern u8 pci_cache_line_size;

extern unsigned long pci_hotplug_io_size;
extern unsigned long pci_hotplug_mem_size;
+extern unsigned long pci_hotplug_mem_pref_size;
extern unsigned long pci_hotplug_bus_size;

/* Architecture-specific versions may override these (weak) */
--
2.20.1