From: Jan Beulich <jbeulich@suse.com>
Date: Mon, 14 Feb 2022 09:05:38 +0000 (+0100)
Subject: x86/Intel: skip CORE_THREAD_COUNT read on family 0xf
X-Git-Tag: archive/raspbian/4.17.0-1+rpi1^2~33^2~1044
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=9112d19853bc509b9c9997757393688657d5a087;p=xen.git

x86/Intel: skip CORE_THREAD_COUNT read on family 0xf

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

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
---

diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index cbeeb19903..db27bc3f64 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -453,7 +453,8 @@ static bool __init check_smt_enabled(void)
      * At the time of writing, it is almost completely undocumented, so isn't
      * virtualised reliably.
      */
-    if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && !cpu_has_hypervisor &&
+    if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
+         boot_cpu_data.x86 != 0xf && !cpu_has_hypervisor &&
          !rdmsr_safe(MSR_INTEL_CORE_THREAD_COUNT, val) )
         return (MASK_EXTR(val, MSR_CTC_CORE_MASK) !=
                 MASK_EXTR(val, MSR_CTC_THREAD_MASK));