Author: alc
Date: Tue Mar 2 16:29:08 2010
New Revision: 204584
URL: http://svn.freebsd.org/changeset/base/204584
Log:
MFC r204420
When running as a guest operating system, the FreeBSD kernel must assume
that the virtual machine monitor has enabled machine check exceptions.
Unfortunately, on AMD Family 10h processors the machine check hardware
has a bug (Erratum 383) that can result in a false machine check exception
when a superpage promotion occurs. Thus, I am disabling superpage
promotion when the FreeBSD kernel is running as a guest operating system
on an AMD Family 10h processor.
Modified:
stable/8/sys/amd64/amd64/pmap.c
stable/8/sys/i386/i386/pmap.c
stable/8/sys/kern/subr_param.c
stable/8/sys/sys/systm.h
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
stable/8/sys/dev/xen/xenpci/ (props changed)
stable/8/sys/netinet/ (props changed)
Modified: stable/8/sys/amd64/amd64/pmap.c
==============================================================================
--- stable/8/sys/amd64/amd64/pmap.c Tue Mar 2 16:25:07 2010
(r204583)
+++ stable/8/sys/amd64/amd64/pmap.c Tue Mar 2 16:29:08 2010
(r204584)
@@ -654,6 +654,15 @@ pmap_init(void)
pv_entry_high_water = 9 * (pv_entry_max / 10);
/*
+ * Disable large page mappings by default if the kernel is running in
+ * a virtual machine on an AMD Family 10h processor. This is a work-
+ * around for Erratum 383.
+ */
+ if (vm_guest == VM_GUEST_VM && cpu_vendor_id == CPU_VENDOR_AMD &&
+ CPUID_TO_FAMILY(cpu_id) == 0x10)
+ pg_ps_enabled = 0;
+
+ /*
* Are large page mappings enabled?
*/
TUNABLE_INT_FETCH("vm.pmap.pg_ps_enabled", &pg_ps_enabled);
Modified: stable/8/sys/i386/i386/pmap.c
==============================================================================
--- stable/8/sys/i386/i386/pmap.c Tue Mar 2 16:25:07 2010
(r204583)
+++ stable/8/sys/i386/i386/pmap.c Tue Mar 2 16:29:08 2010
(r204584)
@@ -678,6 +678,15 @@ pmap_init(void)
pv_entry_high_water = 9 * (pv_entry_max / 10);
/*
+ * Disable large page mappings by default if the kernel is running in
+ * a virtual machine on an AMD Family 10h processor. This is a work-
+ * around for Erratum 383.
+ */
+ if (vm_guest == VM_GUEST_VM && cpu_vendor_id == CPU_VENDOR_AMD &&
+ CPUID_TO_FAMILY(cpu_id) == 0x10)
+ pg_ps_enabled = 0;
+
+ /*
* Are large page mappings enabled?
*/
TUNABLE_INT_FETCH("vm.pmap.pg_ps_enabled", &pg_ps_enabled);
Modified: stable/8/sys/kern/subr_param.c
==============================================================================
--- stable/8/sys/kern/subr_param.c Tue Mar 2 16:25:07 2010
(r204583)
+++ stable/8/sys/kern/subr_param.c Tue Mar 2 16:29:08 2010
(r204584)
@@ -74,10 +74,6 @@ __FBSDID("$FreeBSD$");
#define MAXFILES (maxproc * 2)
#endif
-/* Values of enum VM_GUEST members are used as indices in
- * vm_guest_sysctl_names */
-enum VM_GUEST { VM_GUEST_NO = 0, VM_GUEST_VM, VM_GUEST_XEN };
-
static int sysctl_kern_vm_guest(SYSCTL_HANDLER_ARGS);
int hz;
@@ -137,6 +133,10 @@ SYSCTL_PROC(_kern, OID_AUTO, vm_guest, C
*/
struct buf *swbuf;
+/*
+ * The elements of this array are ordered based upon the values of the
+ * corresponding enum VM_GUEST members.
+ */
static const char *const vm_guest_sysctl_names[] = {
"none",
"generic",
Modified: stable/8/sys/sys/systm.h
==============================================================================
--- stable/8/sys/sys/systm.h Tue Mar 2 16:25:07 2010 (r204583)
+++ stable/8/sys/sys/systm.h Tue Mar 2 16:29:08 2010 (r204584)
@@ -65,6 +65,9 @@ extern int bootverbose; /* nonzero to p
extern int maxusers; /* system tune hint */
extern int ngroups_max; /* max # of supplemental groups */
+extern int vm_guest; /* Running as virtual machine guest? */
+
+enum VM_GUEST { VM_GUEST_NO = 0, VM_GUEST_VM, VM_GUEST_XEN };
#ifdef INVARIANTS /* The option is always available */
#define KASSERT(exp,msg) do {
\
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