x86/tsx: Minor cleanup and improvements

* Introduce cpu_has_arch_caps and replace boot_cpu_has(X86_FEATURE_ARCH_CAPS)
 * Read CPUID data into the appropriate boot_cpu_data.x86_capability[]
   element, as subsequent changes are going to need more cpu_has_* logic.
 * Use the hi/lo MSR helpers, which substantially improves code generation.

No practical change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

xen/arch/x86/cpuid.c

@@ -747,7 +747,7 @@ int init_domain_cpuid_policy(struct domain *d)
      * so dom0 can turn off workarounds as appropriate.  Temporary, until the
      * domain policy logic gains a better understanding of MSRs.
      */
-    if ( is_hardware_domain(d) && boot_cpu_has(X86_FEATURE_ARCH_CAPS) )
+    if ( is_hardware_domain(d) && cpu_has_arch_caps )
         p->feat.arch_caps = true;
 
     d->arch.cpuid = p;

xen/arch/x86/hvm/vmx/vmx.c

@@ -2566,7 +2566,7 @@ static bool __init has_if_pschange_mc(void)
     if ( cpu_has_hypervisor )
         return false;
 
-    if ( boot_cpu_has(X86_FEATURE_ARCH_CAPS) )
+    if ( cpu_has_arch_caps )
         rdmsrl(MSR_ARCH_CAPABILITIES, caps);
 
     if ( caps & ARCH_CAPS_IF_PSCHANGE_MC_NO )

xen/arch/x86/msr.c

@@ -136,7 +136,7 @@ int init_domain_msr_policy(struct domain *d)
      * so dom0 can turn off workarounds as appropriate.  Temporary, until the
      * domain policy logic gains a better understanding of MSRs.
      */
-    if ( is_hardware_domain(d) && boot_cpu_has(X86_FEATURE_ARCH_CAPS) )
+    if ( is_hardware_domain(d) && cpu_has_arch_caps )
     {
         uint64_t val;
 

xen/arch/x86/spec_ctrl.c

@@ -885,7 +885,7 @@ void __init init_speculation_mitigations(void)
     bool cpu_has_bug_taa;
     uint64_t caps = 0;
 
-    if ( boot_cpu_has(X86_FEATURE_ARCH_CAPS) )
+    if ( cpu_has_arch_caps )
         rdmsrl(MSR_ARCH_CAPABILITIES, caps);
 
     hw_smt_enabled = check_smt_enabled();

xen/arch/x86/tsx.c

@@ -34,15 +34,18 @@ void tsx_init(void)
 {
     /*
      * This function is first called between microcode being loaded, and CPUID
-     * being scanned generally.  Calculate from raw data whether MSR_TSX_CTRL
-     * is available.
+     * being scanned generally.  Read into boot_cpu_data.x86_capability[] for
+     * the cpu_has_* bits we care about using here.
      */
     if ( unlikely(cpu_has_tsx_ctrl < 0) )
     {
         uint64_t caps = 0;
 
-        if ( boot_cpu_data.cpuid_level >= 7 &&
-             (cpuid_count_edx(7, 0) & cpufeat_mask(X86_FEATURE_ARCH_CAPS)) )
+        if ( boot_cpu_data.cpuid_level >= 7 )
+            boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_ARCH_CAPS)]
+                = cpuid_count_edx(7, 0);
+
+        if ( cpu_has_arch_caps )
             rdmsrl(MSR_ARCH_CAPABILITIES, caps);
 
         cpu_has_tsx_ctrl = !!(caps & ARCH_CAPS_TSX_CTRL);
@@ -74,18 +77,18 @@ void tsx_init(void)
 
     if ( cpu_has_tsx_ctrl )
     {
-        uint64_t val;
+        uint32_t hi, lo;
 
-        rdmsrl(MSR_TSX_CTRL, val);
+        rdmsr(MSR_TSX_CTRL, lo, hi);
 
         /* Check bottom bit only.  Higher bits are various sentinels. */
         rtm_disabled = !(opt_tsx & 1);
 
-        val &= ~(TSX_CTRL_RTM_DISABLE | TSX_CTRL_CPUID_CLEAR);
+        lo &= ~(TSX_CTRL_RTM_DISABLE | TSX_CTRL_CPUID_CLEAR);
         if ( rtm_disabled )
-            val |= TSX_CTRL_RTM_DISABLE | TSX_CTRL_CPUID_CLEAR;
+            lo |= TSX_CTRL_RTM_DISABLE | TSX_CTRL_CPUID_CLEAR;
 
-        wrmsrl(MSR_TSX_CTRL, val);
+        wrmsr(MSR_TSX_CTRL, lo, hi);
     }
     else if ( opt_tsx >= 0 )
         printk_once(XENLOG_WARNING

xen/include/asm-x86/cpufeature.h

@@ -133,6 +133,7 @@
 #define cpu_has_avx512_vp2intersect boot_cpu_has(X86_FEATURE_AVX512_VP2INTERSECT)
 #define cpu_has_tsx_force_abort boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT)
 #define cpu_has_serialize       boot_cpu_has(X86_FEATURE_SERIALIZE)
+#define cpu_has_arch_caps       boot_cpu_has(X86_FEATURE_ARCH_CAPS)
 
 /* CPUID level 0x00000007:1.eax */
 #define cpu_has_avx_vnni        boot_cpu_has(X86_FEATURE_AVX_VNNI)