Intel 253668-032US ユーザーズマニュアル

15-24   Vol. 3

MACHINE-CHECK ARCHITECTURE

15.6.1 

Detection of Software Error Recovery Support

Software must use bit 24 of IA32_MCG_CAP (MCG_SER_P) to detect the 

presence of software error recovery support (see Figure 15-2). When 

IA32_MCG_CAP[24] is set, this indicates that the processor supports soft-

ware error recovery. When this bit is clear, this indicates that there is no 

support for error recovery from the processor and the primary responsibility 

of the machine check handler is logging the machine check error information 

and shutting down the system. 
The new class of architectural MCA errors from which system software can 

attempt recovery is called Uncorrected Recoverable (UCR) Errors. UCR 

errors are uncorrected errors that have been detected and signaled but have 

not corrupted the processor context. For certain UCR errors, this means that 

once system software has performed a certain recovery action, it is possible 

to continue execution on this processor. UCR error reporting provides an 

error containment mechanism for data poisoning. The machine check 

handler will use the error log information from the error reporting registers 

to analyze and implement specific error recovery actions for UCR errors. 

15.6.2 

UCR Error Reporting and Logging

IA32_MCi_STATUS MSR is used for reporting UCR errors and existing 

corrected or uncorrected errors. The definitions of IA32_MCi_STATUS, 

including bit fields to identify UCR errors, is shown in Figure 15-5. UCR 

errors can be signaled through either the corrected machine check interrupt 

(CMCI) or machine check exception (MCE) path depending on the type of the 

UCR error. 
When IA32_MCG_CAP[24] is set, a UCR error is indicated by the following 

bit settings in the IA32_MCi_STATUS register: 

•

Valid (bit 63) = 1

•

UC (bit 61) = 1

•

PCC (bit 57) = 0

Additional information from the IA32_MCi_MISC and the IA32_MCi_ADDR 

registers for the UCR error are available when the ADDRV and the MISCV 

flags in the IA32_MCi_STATUS register are set (see Section 15.3.2.4). The 

MCA error code field of the IA32_MCi_STATUS register indicates the type of 

UCR error. System software can interpret the MCA error code field to analyze 

and identify the necessary recovery action for the given UCR error.
In addition, the IA32_MCi_STATUS register bit fields, bits 56:55, are defined 

(see Figure 15-5) to provide additional information to help system software 

to properly identify the necessary recovery action for the UCR error: