[XEN PATCH 2/2] x86: Refactor LBR feature to MSR_DEBUGCTL feature

[Matthew Barnes <matthew.barnes@cloud.com>]

Last Branch Record and Bus Lock Detect both belong to the same MSR.

The same mechanism that restores LBR also restores BLD.

Therefore, the name of the feature that enables this mechanism should
reflect restoring the MSR, instead of one field.

No functional change.

Signed-off-by: Matthew Barnes <matthew.barnes@cloud.com>
---
 xen/arch/x86/hvm/vmx/entry.S           | 4 ++--
 xen/arch/x86/include/asm/cpufeature.h  | 2 +-
 xen/arch/x86/include/asm/cpufeatures.h | 2 +-
 xen/arch/x86/traps.c                   | 6 +++---
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/entry.S b/xen/arch/x86/hvm/vmx/entry.S
index a0148f78584d..acfdc370289d 100644
--- a/xen/arch/x86/hvm/vmx/entry.S
+++ b/xen/arch/x86/hvm/vmx/entry.S
@@ -47,12 +47,12 @@ ENTRY(vmx_asm_vmexit_handler)
 
         /* Hardware clears MSR_DEBUGCTL on VMExit.  Reinstate it if debugging Xen. */
         mov host_msr_debugctl(%rip), %eax
-        .macro restore_lbr
+        .macro restore_msr_debugctl
             mov $MSR_IA32_DEBUGCTLMSR, %ecx
             xor %edx, %edx
             wrmsr
         .endm
-        ALTERNATIVE "", restore_lbr, X86_FEATURE_XEN_LBR
+        ALTERNATIVE "", restore_msr_debugctl, X86_FEATURE_XEN_MSR_DEBUGCTL
 
         mov  %rsp,%rdi
         call vmx_vmexit_handler
diff --git a/xen/arch/x86/include/asm/cpufeature.h b/xen/arch/x86/include/asm/cpufeature.h
index 9bc553681f4a..084501c76a03 100644
--- a/xen/arch/x86/include/asm/cpufeature.h
+++ b/xen/arch/x86/include/asm/cpufeature.h
@@ -223,7 +223,7 @@ static inline bool boot_cpu_has(unsigned int feat)
 #define cpu_has_aperfmperf      boot_cpu_has(X86_FEATURE_APERFMPERF)
 #define cpu_has_lfence_dispatch boot_cpu_has(X86_FEATURE_LFENCE_DISPATCH)
 #define cpu_has_nscb            boot_cpu_has(X86_FEATURE_NSCB)
-#define cpu_has_xen_lbr         boot_cpu_has(X86_FEATURE_XEN_LBR)
+#define cpu_has_xen_msr_debugctl boot_cpu_has(X86_FEATURE_XEN_MSR_DEBUGCTL)
 #define cpu_has_xen_shstk       (IS_ENABLED(CONFIG_XEN_SHSTK) && \
                                  boot_cpu_has(X86_FEATURE_XEN_SHSTK))
 #define cpu_has_xen_ibt         (IS_ENABLED(CONFIG_XEN_IBT) && \
diff --git a/xen/arch/x86/include/asm/cpufeatures.h b/xen/arch/x86/include/asm/cpufeatures.h
index 7e8221fd85dd..060d7c1d5c9e 100644
--- a/xen/arch/x86/include/asm/cpufeatures.h
+++ b/xen/arch/x86/include/asm/cpufeatures.h
@@ -34,7 +34,7 @@ XEN_CPUFEATURE(SC_RSB_PV,         X86_SYNTH(18)) /* RSB overwrite needed for PV
 XEN_CPUFEATURE(SC_RSB_HVM,        X86_SYNTH(19)) /* RSB overwrite needed for HVM */
 XEN_CPUFEATURE(XEN_SELFSNOOP,     X86_SYNTH(20)) /* SELFSNOOP gets used by Xen itself */
 XEN_CPUFEATURE(SC_MSR_IDLE,       X86_SYNTH(21)) /* Clear MSR_SPEC_CTRL on idle */
-XEN_CPUFEATURE(XEN_LBR,           X86_SYNTH(22)) /* Xen uses MSR_DEBUGCTL.LBR */
+XEN_CPUFEATURE(XEN_MSR_DEBUGCTL,  X86_SYNTH(22)) /* Xen uses MSR_DEBUGCTL */
 XEN_CPUFEATURE(SC_DIV,            X86_SYNTH(23)) /* DIV scrub needed */
 XEN_CPUFEATURE(SC_RSB_IDLE,       X86_SYNTH(24)) /* RSB overwrite needed for idle. */
 XEN_CPUFEATURE(SC_VERW_IDLE,      X86_SYNTH(25)) /* VERW used by Xen for idle */
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 7d8eee013d00..16bef5d76620 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1940,7 +1940,7 @@ void asmlinkage do_debug(struct cpu_user_regs *regs)
         return;
 
     /* #DB automatically disabled LBR.  Reinstate it if debugging Xen. */
-    if ( cpu_has_xen_lbr )
+    if ( cpu_has_xen_msr_debugctl )
         wrmsrl(MSR_IA32_DEBUGCTLMSR, host_msr_debugctl);
 
     if ( !guest_mode(regs) )
@@ -2129,10 +2129,10 @@ void percpu_traps_init(void)
             return;
         }
 
-        setup_force_cpu_cap(X86_FEATURE_XEN_LBR);
+        setup_force_cpu_cap(X86_FEATURE_XEN_MSR_DEBUGCTL);
     }
 
-    if ( cpu_has_xen_lbr )
+    if ( cpu_has_xen_msr_debugctl )
     {
         host_msr_debugctl |= IA32_DEBUGCTLMSR_LBR;
         wrmsrl(MSR_IA32_DEBUGCTLMSR, host_msr_debugctl);
-- 
2.34.1