[PATCH 1/3] x86/Intel: skip PLATFORM_INFO reads on family 0xf

[Jan Beulich <jbeulich@suse.com>]

This avoids unnecessary (and always somewhat scary) log messages for the
recovered from #GP(0).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
Perhaps even use "!= 6" in at least the CPUID-faulting family check?

--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -127,9 +127,12 @@ bool __init probe_cpuid_faulting(void)
 
 	/*
 	 * Don't bother looking for CPUID faulting if we aren't virtualised on
-	 * AMD or Hygon hardware - it won't be present.
+	 * AMD or Hygon hardware - it won't be present.  Likewise for Fam0F
+	 * Intel hardware.
 	 */
-	if ((boot_cpu_data.x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)) &&
+	if (((boot_cpu_data.x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)) ||
+	     ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
+	      boot_cpu_data.x86 == 0xf)) &&
 	    !cpu_has_hypervisor)
 		return false;
 
--- a/xen/arch/x86/cpu/intel.c
+++ b/xen/arch/x86/cpu/intel.c
@@ -455,7 +455,7 @@ static void intel_log_freq(const struct
         }
     }
 
-    if ( rdmsr_safe(MSR_INTEL_PLATFORM_INFO, msrval) )
+    if ( c->x86 == 0xf || rdmsr_safe(MSR_INTEL_PLATFORM_INFO, msrval) )
         return;
     max_ratio = msrval >> 8;