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cpucontrol: improve Intel microcode revision check

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According to the Intel SDM (Volme 3, 9.11.7) the BIOS signature MSR
should be zeroed before executing cpuid (although in practice it does
not seem to matter).

PR:		192487
Submitted by:	Dan Lukes
Reported by:	Henrique de Moraes Holschuh
MFC after:	3 days
This commit is contained in:
Ed Maste 2018-05-12 15:34:35 +00:00
parent 0fb349906e
commit 09e24fbe18
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=333569
1 changed files with 8 additions and 1 deletions
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9
usr.sbin/cpucontrol/intel.c
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@ -95,7 +95,8 @@ intel_update(const char *dev, const char *path)
void *fw_data;
size_t data_size, total_size;
cpuctl_msr_args_t msrargs = {
.msr = MSR_IA32_PLATFORM_ID,
.msr = MSR_BIOS_SIGN,
.data = 0,
};
cpuctl_cpuid_args_t idargs = {
.level = 1, /* Signature. */
@ -115,12 +116,18 @@ intel_update(const char *dev, const char *path)
WARN(0, "could not open %s for writing", dev);
return;
}
error = ioctl(devfd, CPUCTL_WRMSR, &msrargs);
if (error < 0) {
WARN(0, "ioctl(%s)", dev);
goto fail;
}
error = ioctl(devfd, CPUCTL_CPUID, &idargs);
if (error < 0) {
WARN(0, "ioctl(%s)", dev);
goto fail;
}
signature = idargs.data[0];
msrargs.msr = MSR_IA32_PLATFORM_ID;
error = ioctl(devfd, CPUCTL_RDMSR, &msrargs);
if (error < 0) {
WARN(0, "ioctl(%s)", dev);