[Xen-devel] [PATCH v4 3/8] x86: log XPTI enabled status

["Jan Beulich" <JBeulich@xxxxxxxx>]

At the same time also report the state of the two defined
ARCH_CAPABILITIES MSR bits. To avoid further complicating the
conditional around that printk(), drop it (it's a debug level one only
anyway).

Issue the main message without any XENLOG_*, and also drop XENLOG_INFO
from the respective BTI message, to make sure they're visible at default
log level also in release builds.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Tested-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
v4: Drop XENLOG_INFO (also from respective BTI message).
v2: Re-base over split off earlier patch. Drop MSR_ from
    MSR_ARCH_CAPABILITIES_*. Drop conditional around debug printk().

--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -21,7 +21,7 @@
 #include <xen/lib.h>
 
 #include <asm/microcode.h>
-#include <asm/msr-index.h>
+#include <asm/msr.h>
 #include <asm/processor.h>
 #include <asm/spec_ctrl.h>
 #include <asm/spec_ctrl_asm.h>
@@ -100,30 +100,31 @@ custom_param("bti", parse_bti);
 static void __init print_details(enum ind_thunk thunk)
 {
     unsigned int _7d0 = 0, e8b = 0, tmp;
+    uint64_t caps = 0;
 
     /* Collect diagnostics about available mitigations. */
     if ( boot_cpu_data.cpuid_level >= 7 )
         cpuid_count(7, 0, &tmp, &tmp, &tmp, &_7d0);
     if ( boot_cpu_data.extended_cpuid_level >= 0x80000008 )
         cpuid(0x80000008, &tmp, &e8b, &tmp, &tmp);
+    if ( _7d0 & cpufeat_mask(X86_FEATURE_ARCH_CAPS) )
+        rdmsrl(MSR_ARCH_CAPABILITIES, caps);
 
     printk(XENLOG_DEBUG "Speculative mitigation facilities:\n");
 
     /* Hardware features which pertain to speculative mitigations. */
-    if ( (_7d0 & (cpufeat_mask(X86_FEATURE_IBRSB) |
-                  cpufeat_mask(X86_FEATURE_STIBP))) ||
-         (e8b & cpufeat_mask(X86_FEATURE_IBPB)) )
-        printk(XENLOG_DEBUG "  Hardware features:%s%s%s\n",
-               (_7d0 & cpufeat_mask(X86_FEATURE_IBRSB)) ? " IBRS/IBPB" : "",
-               (_7d0 & cpufeat_mask(X86_FEATURE_STIBP)) ? " STIBP"     : "",
-               (e8b  & cpufeat_mask(X86_FEATURE_IBPB))  ? " IBPB"      : "");
+    printk(XENLOG_DEBUG "  Hardware features:%s%s%s%s%s\n",
+           (_7d0 & cpufeat_mask(X86_FEATURE_IBRSB)) ? " IBRS/IBPB" : "",
+           (_7d0 & cpufeat_mask(X86_FEATURE_STIBP)) ? " STIBP"     : "",
+           (e8b  & cpufeat_mask(X86_FEATURE_IBPB))  ? " IBPB"      : "",
+           (caps & ARCH_CAPABILITIES_IBRS_ALL)      ? " IBRS_ALL"  : "",
+           (caps & ARCH_CAPABILITIES_RDCL_NO)       ? " RDCL_NO"   : "");
 
     /* Compiled-in support which pertains to BTI mitigations. */
     if ( IS_ENABLED(CONFIG_INDIRECT_THUNK) )
         printk(XENLOG_DEBUG "  Compiled-in support: INDIRECT_THUNK\n");
 
-    printk(XENLOG_INFO
-           "BTI mitigations: Thunk %s, Others:%s%s%s%s\n",
+    printk("BTI mitigations: Thunk %s, Others:%s%s%s%s\n",
            thunk == THUNK_NONE      ? "N/A" :
            thunk == THUNK_RETPOLINE ? "RETPOLINE" :
            thunk == THUNK_LFENCE    ? "LFENCE" :
@@ -133,6 +134,9 @@ static void __init print_details(enum in
            opt_ibpb                                  ? " IBPB"       : "",
            boot_cpu_has(X86_FEATURE_RSB_NATIVE)      ? " RSB_NATIVE" : "",
            boot_cpu_has(X86_FEATURE_RSB_VMEXIT)      ? " RSB_VMEXIT" : "");
+
+    printk("XPTI: %s\n",
+           boot_cpu_has(X86_FEATURE_NO_XPTI) ? "disabled" : "enabled");
 }
 
 /* Calculate whether Retpoline is known-safe on this CPU. */




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