svn commit: r333569 - head/usr.sbin/cpucontrol

[Ed Maste]

Author: emaste
Date: Sat May 12 15:34:35 2018
New Revision: 333569
URL: https://svnweb.freebsd.org/changeset/base/333569

Log:
  cpucontrol: improve Intel microcode revision check
  
  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

Modified:
  head/usr.sbin/cpucontrol/intel.c

Modified: head/usr.sbin/cpucontrol/intel.c
==============================================================================
--- head/usr.sbin/cpucontrol/intel.c	Sat May 12 15:20:39 2018	(r333568)
+++ head/usr.sbin/cpucontrol/intel.c	Sat May 12 15:34:35 2018	(r333569)
@@ -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);