[tip:x86/cpu] x86, cpu, amd: Fix crash as Xen Dom0 on AMD Trinity systems
From: tip-bot for Andre Przywara
Date: Thu Jun 07 2012 - 18:00:39 EST
Commit-ID: 169e9cbd77db23fe50bc8ba68bf081adb67b4220
Gitweb: http://git.kernel.org/tip/169e9cbd77db23fe50bc8ba68bf081adb67b4220
Author: Andre Przywara <andre.przywara@xxxxxxx>
AuthorDate: Fri, 1 Jun 2012 16:52:37 +0200
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Thu, 7 Jun 2012 11:43:30 -0700
x86, cpu, amd: Fix crash as Xen Dom0 on AMD Trinity systems
f7f286a910221 ("x86/amd: Re-enable CPU topology extensions in case BIOS
has disabled it") wrongfully added code which used the AMD-specific
{rd,wr}msr variants for no real reason.
This caused boot panics on xen which wasn't initializing the
{rd,wr}msr_safe_regs pv_ops members properly.
This, in turn, caused a heated discussion leading to us reviewing all
uses of the AMD-specific variants and removing them where unneeded
(almost everywhere except an obscure K8 BIOS fix, see 6b0f43ddfa358).
Finally, this patch switches to the standard {rd,wr}msr*_safe* variants
which should've been used in the first place anyway and avoided unneeded
excitation with xen.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Link: http://lkml.kernel.org/r/1338562358-28182-4-git-send-email-bp@xxxxxxxxx
Cc: Andreas Herrmann <andreas.herrmann3@xxxxxxx>
Link: <http://lkml.kernel.org/r/1338383402-3838-1-git-send-email-andre.przywara@xxxxxxx>
[Boris: correct and expand commit message]
Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/kernel/cpu/amd.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 146bb62..80ccd99 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -586,9 +586,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
!cpu_has(c, X86_FEATURE_TOPOEXT)) {
u64 val;
- if (!rdmsrl_amd_safe(0xc0011005, &val)) {
+ if (!rdmsrl_safe(0xc0011005, &val)) {
val |= 1ULL << 54;
- wrmsrl_amd_safe(0xc0011005, val);
+ checking_wrmsrl(0xc0011005, val);
rdmsrl(0xc0011005, val);
if (val & (1ULL << 54)) {
set_cpu_cap(c, X86_FEATURE_TOPOEXT);
--
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