From 169e9cbd77db23fe50bc8ba68bf081adb67b4220 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Fri, 1 Jun 2012 16:52:37 +0200 Subject: [PATCH] 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 Link: http://lkml.kernel.org/r/1338562358-28182-4-git-send-email-bp@amd64.org Cc: Andreas Herrmann Link: [Boris: correct and expand commit message] Signed-off-by: Borislav Petkov Acked-by: Konrad Rzeszutek Wilk Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/amd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 146bb6218ee..80ccd99542e 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);