[PATCH 3/5] x86/spec-ctrl: Remove open-coded check of SVM_FEATURE_SPEC_CTRL

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Now that the SVM feature leaf has been included in normal feature handling, it
is available early enough for init_speculation_mitigations() to use.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Xenia Ragiadakou <xenia.ragiadakou@xxxxxxx>
CC: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxx>
CC: Andrei Semenov <andrei.semenov@xxxxxxxx>
CC: Vaishali Thakkar <vaishali.thakkar@xxxxxxxxxx>
---
 xen/arch/x86/include/asm/cpufeature.h | 3 +++
 xen/arch/x86/spec_ctrl.c              | 7 +------
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/include/asm/cpufeature.h 
b/xen/arch/x86/include/asm/cpufeature.h
index 9bc553681f4a..77cfd900cb56 100644
--- a/xen/arch/x86/include/asm/cpufeature.h
+++ b/xen/arch/x86/include/asm/cpufeature.h
@@ -217,6 +217,9 @@ static inline bool boot_cpu_has(unsigned int feat)
 #define cpu_has_rfds_no         boot_cpu_has(X86_FEATURE_RFDS_NO)
 #define cpu_has_rfds_clear      boot_cpu_has(X86_FEATURE_RFDS_CLEAR)
 
+/* CPUID level 0x8000000a.edx */
+#define cpu_has_v_spec_ctrl     boot_cpu_has(X86_FEATURE_V_SPEC_CTRL)
+
 /* Synthesized. */
 #define cpu_has_arch_perfmon    boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
 #define cpu_has_cpuid_faulting  boot_cpu_has(X86_FEATURE_CPUID_FAULTING)
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index 40f6ae017010..0bda9d01def5 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -11,7 +11,6 @@
 #include <xen/warning.h>
 
 #include <asm/amd.h>
-#include <asm/hvm/svm/svm.h>
 #include <asm/intel-family.h>
 #include <asm/microcode.h>
 #include <asm/msr.h>
@@ -1896,12 +1895,8 @@ void __init init_speculation_mitigations(void)
          *
          * No need for SCF_ist_sc_msr because Xen's value is restored
          * atomically WRT NMIs in the VMExit path.
-         *
-         * TODO: Adjust cpu_has_svm_spec_ctrl to be usable earlier on boot.
          */
-        if ( opt_msr_sc_hvm &&
-             (boot_cpu_data.extended_cpuid_level >= 0x8000000aU) &&
-             (cpuid_edx(0x8000000aU) & (1u << SVM_FEATURE_SPEC_CTRL)) )
+        if ( opt_msr_sc_hvm && cpu_has_v_spec_ctrl )
             setup_force_cpu_cap(X86_FEATURE_SC_MSR_HVM);
     }
 
-- 
2.30.2