Module Name: src
Committed By: bouyer
Date: Tue May 5 16:58:11 UTC 2020
Modified Files:
src/sys/dev/pci: pci_map.c
Log Message:
disable I/O or mem decode before probing BAR size.
Bar size is probed writing 0xffffffff to the BAR and reading back; but while
doing this the decoding address is not guaranteed to be valid and could have
side effect.
Xen PVH enforces disabling decoding before writing to a BAR.
Proposed on tech-kern@, got positive comments
To generate a diff of this commit:
cvs rdiff -u -r1.39 -r1.40 src/sys/dev/pci/pci_map.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/pci/pci_map.c
diff -u src/sys/dev/pci/pci_map.c:1.39 src/sys/dev/pci/pci_map.c:1.40
--- src/sys/dev/pci/pci_map.c:1.39 Mon Dec 2 17:13:13 2019
+++ src/sys/dev/pci/pci_map.c Tue May 5 16:58:11 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: pci_map.c,v 1.39 2019/12/02 17:13:13 riastradh Exp $ */
+/* $NetBSD: pci_map.c,v 1.40 2020/05/05 16:58:11 bouyer Exp $ */
/*-
* Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -34,7 +34,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pci_map.c,v 1.39 2019/12/02 17:13:13 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pci_map.c,v 1.40 2020/05/05 16:58:11 bouyer Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -49,7 +49,7 @@ static int
pci_io_find(pci_chipset_tag_t pc, pcitag_t tag, int reg, pcireg_t type,
bus_addr_t *basep, bus_size_t *sizep, int *flagsp)
{
- pcireg_t address, mask;
+ pcireg_t address, mask, csr;
int s;
if (reg < PCI_MAPREG_START ||
@@ -75,9 +75,18 @@ pci_io_find(pci_chipset_tag_t pc, pcitag
*/
s = splhigh();
address = pci_conf_read(pc, tag, reg);
+ /*
+ * Disable decoding via the command register before writing to the
+ * BAR register. Changing the decoding address to all-one is
+ * not a valid address and could have side effects.
+ */
+ csr = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG,
+ csr & ~PCI_COMMAND_IO_ENABLE) ;
pci_conf_write(pc, tag, reg, 0xffffffff);
mask = pci_conf_read(pc, tag, reg);
pci_conf_write(pc, tag, reg, address);
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG, csr);
splx(s);
if (PCI_MAPREG_TYPE(address) != PCI_MAPREG_TYPE_IO) {
@@ -107,6 +116,7 @@ pci_mem_find(pci_chipset_tag_t pc, pcita
pcireg_t address, mask, address1 = 0, mask1 = 0xffffffff;
uint64_t waddress, wmask;
int s, is64bit, isrom;
+ pcireg_t csr;
is64bit = (PCI_MAPREG_MEM_TYPE(type) == PCI_MAPREG_MEM_TYPE_64BIT);
isrom = (reg == PCI_MAPREG_ROM);
@@ -138,6 +148,14 @@ pci_mem_find(pci_chipset_tag_t pc, pcita
*/
s = splhigh();
address = pci_conf_read(pc, tag, reg);
+ csr = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
+ /*
+ * Disable decoding via the command register before writing to the
+ * BAR register. Changing the decoding address to all-one is
+ * not a valid address and could have side effects.
+ */
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG,
+ csr & ~PCI_COMMAND_MEM_ENABLE) ;
pci_conf_write(pc, tag, reg, 0xffffffff);
mask = pci_conf_read(pc, tag, reg);
pci_conf_write(pc, tag, reg, address);
@@ -149,6 +167,7 @@ pci_mem_find(pci_chipset_tag_t pc, pcita
pci_conf_write(pc, tag, reg + 4, address1);
}
}
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG, csr);
splx(s);
if (!isrom) {
@@ -240,14 +259,28 @@ pci_mapreg_type(pci_chipset_tag_t pc, pc
int
pci_mapreg_probe(pci_chipset_tag_t pc, pcitag_t tag, int reg, pcireg_t *typep)
{
- pcireg_t address, mask;
+ pcireg_t address, mask, csr;
int s;
s = splhigh();
address = pci_conf_read(pc, tag, reg);
+ /*
+ * Disable decoding via the command register before writing to the
+ * BAR register. Changing the decoding address to all-one is
+ * not a valid address and could have side effects.
+ */
+ csr = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
+ if (PCI_MAPREG_TYPE(address) == PCI_MAPREG_TYPE_IO) {
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG,
+ csr & ~PCI_COMMAND_IO_ENABLE);
+ } else {
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG,
+ csr & ~PCI_COMMAND_MEM_ENABLE);
+ }
pci_conf_write(pc, tag, reg, 0xffffffff);
mask = pci_conf_read(pc, tag, reg);
pci_conf_write(pc, tag, reg, address);
+ pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG, csr);
splx(s);
if (mask == 0) /* unimplemented mapping register */
