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Re: [Xen-devel] [PATCH 10/19] x86/mce: always write 0 to MSR_IA32_MCG_STATUS on Intel CPU
On 02/17/2017 05:26 AM, Jan Beulich wrote:
On 17.02.17 at 07:39, <haozhong.zhang@xxxxxxxxx> wrote:
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -538,7 +538,14 @@ void mcheck_cmn_handler(const struct cpu_user_regs *regs)
gstatus = mca_rdmsr(MSR_IA32_MCG_STATUS);
if ((gstatus & MCG_STATUS_MCIP) != 0) {
mce_printk(MCE_CRITICAL, "MCE: Clear MCIP@ last step");
- mca_wrmsr(MSR_IA32_MCG_STATUS, gstatus & ~MCG_STATUS_MCIP);
+ if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL )
+ /*
+ * Intel SDM 3: An attempt to write to IA32_MCG_STATUS
+ * with any value other than 0 would result in #GP.
+ */
+ mca_wrmsr(MSR_IA32_MCG_STATUS, 0);
+ else
+ mca_wrmsr(MSR_IA32_MCG_STATUS, gstatus & ~MCG_STATUS_MCIP);
I think this wants to be the other way around: Write zero in the
common case, and make an exception for AMD (and that only if
on AMD it's really useful to write other than plain zero). Boris,
Suravee, can you provide some input here please?
I don't see anything stating that writing non-zero values can result in
an exception of any sort. But I am only going by what I see in the
documentation.
-boris
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