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| author | alc <alc@FreeBSD.org> | 2010-02-27 18:00:57 +0000 |
|---|---|---|
| committer | alc <alc@FreeBSD.org> | 2010-02-27 18:00:57 +0000 |
| commit | 83149d5d10417a7749818290fc67c6b1c178ce0a (patch) | |
| tree | eb53149f310d543b56a8e0ae7af18109232c21e4 /sys/amd64 | |
| parent | d828528c4c0fe2bb6a99b6f2d8f4014e2592350b (diff) | |
| download | FreeBSD-src-83149d5d10417a7749818290fc67c6b1c178ce0a.zip FreeBSD-src-83149d5d10417a7749818290fc67c6b1c178ce0a.tar.gz | |
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.
Reviewed by: jhb, kib
MFC after: 3 days
Diffstat (limited to 'sys/amd64')
| -rw-r--r-- | sys/amd64/amd64/pmap.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 9bfb2ab..07db5d1 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -686,6 +686,15 @@ 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); |
