X86_MSR_XCALL(9) x86 X86_MSR_XCALL(9)
NAME
x86_msr_xcallMSR specific cross-call
SYNOPSIS
#include <x86/cpu_msr.h>
void
x86_msr_xcall(void *arg1, void *arg1);
DESCRIPTION
The x86_msr_xcall() function provides a x86-specific IPI handler suitable for use with the xcall(9) interface. It can be used to ensure that a given MSR call is executed on all processors. The prototype follows the xcfunc_t function pointer type and the opaque arg1 pointer is casted to the following structure:
struct msr_rw_info { int msr_read; int msr_type; uint64_t msr_value; uint64_t msr_mask; };
 
This structure must be filled prior to the call. Two fields are compulsory: msr_type is used as the address of the MSR and msr_value is the value to be written. If msr_read is not zero, x86_msr_xcall() will first read from msr_type and then clear the mask specified in msr_mask before the write operation.
EXAMPLES
The following example writes a value zero to the MSR_THERM_CONTROL model-specific register on all processors in the system:
struct msr_rw_info msr; uint64_t xc; msr.msr_value = 0; msr.msr_read = true; msr.msr_type = MSR_THERM_CONTROL; msr.msr_mask = 0x1e; xc = xc_broadcast(0, (xcfunc_t)x86_msr_xcall, &msr, NULL); xc_wait(xc);
SEE ALSO