diff options
| author | Roedel, Joerg <Joerg.Roedel@amd.com> | 2011-05-19 11:13:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-06-23 15:28:35 -0700 |
| commit | 6935afd49db0e94cfd52f32c7548eae48390c39a (patch) | |
| tree | c1a500f9213b014d4425debde2252530e623fec5 | |
| parent | 936107f142c4c05e55de7b1f1c5c049dd0cb91dc (diff) | |
x86, amd: Use _safe() msr access for GartTlbWlk disable code
commit d47cc0db8fd6011de2248df505fc34990b7451bf upstream.
The workaround for Bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=33012
introduced a read and a write to the MC4 mask msr.
Unfortunatly this MSR is not emulated by the KVM hypervisor
so that the kernel will get a #GP and crashes when applying
this workaround when running inside KVM.
This issue was reported as:
https://bugzilla.kernel.org/show_bug.cgi?id=35132
and is fixed with this patch. The change just let the kernel
ignore any #GP it gets while accessing this MSR by using the
_safe msr access methods.
Reported-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index ce87794943f..29dfd22ab64 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -585,10 +585,13 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) * Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=33012 */ u64 mask; + int err; - rdmsrl(MSR_AMD64_MCx_MASK(4), mask); - mask |= (1 << 10); - wrmsrl(MSR_AMD64_MCx_MASK(4), mask); + err = rdmsrl_safe(MSR_AMD64_MCx_MASK(4), &mask); + if (err == 0) { + mask |= (1 << 10); + checking_wrmsrl(MSR_AMD64_MCx_MASK(4), mask); + } } } |