xen/spec-ctrl: Speculative mitigation facilities report wrong status

Booting with spec-ctrl=0 results in Xen printing "None MD_CLEAR".

  (XEN)   Support for HVM VMs: None MD_CLEAR
  (XEN)   Support for PV VMs: None MD_CLEAR

Add a check about X86_FEATURE_MD_CLEAR to avoid to print "None".

Signed-off-by: James Wang <jnwang@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 2adc580bd59f5c3034fd6ecacd5748678373f17a
master date: 2019-07-31 14:53:13 +0100

diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index ba1f058f9d05617645eee26d5a1213c208c72089..2fe16b423d0c1e171349bfbaa21a428b97fcc397 100644 (file)
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -415,6 +415,7 @@ static void __init print_details(enum ind_thunk thunk, uint64_t caps)
     printk("  Support for VMs: PV:%s%s%s%s%s, HVM:%s%s%s%s%s\n",
            (boot_cpu_has(X86_FEATURE_SC_MSR_PV) ||
             boot_cpu_has(X86_FEATURE_SC_RSB_PV) ||
+            boot_cpu_has(X86_FEATURE_MD_CLEAR)  ||
             opt_eager_fpu)                           ? ""               : " None",
            boot_cpu_has(X86_FEATURE_SC_MSR_PV)       ? " MSR_SPEC_CTRL" : "",
            boot_cpu_has(X86_FEATURE_SC_RSB_PV)       ? " RSB"           : "",
@@ -422,6 +423,7 @@ static void __init print_details(enum ind_thunk thunk, uint64_t caps)
            boot_cpu_has(X86_FEATURE_MD_CLEAR)        ? " MD_CLEAR"      : "",
            (boot_cpu_has(X86_FEATURE_SC_MSR_HVM) ||
             boot_cpu_has(X86_FEATURE_SC_RSB_HVM) ||
+            boot_cpu_has(X86_FEATURE_MD_CLEAR)   ||
             opt_eager_fpu)                           ? ""               : " None",
            boot_cpu_has(X86_FEATURE_SC_MSR_HVM)      ? " MSR_SPEC_CTRL" : "",
            boot_cpu_has(X86_FEATURE_SC_RSB_HVM)      ? " RSB"           : "",