x86/monitor: wrap monitor_op under CONFIG_VM_EVENT

Feature monitor_op is based on vm event subsystem, so monitor.o shall be
wrapped under CONFIG_VM_EVENT.
The following functions are only invoked by monitor-op, so they all shall be
wrapped with CONFIG_VM_EVENT (otherwise they will become unreachable and
violate Misra rule 2.1 when VM_EVENT=n):
- hvm_enable_msr_interception
  - hvm_function_table.enable_msr_interception
- hvm_has_set_descriptor_access_existing
  - hvm_function_table.set_descriptor_access_existi
- arch_monitor_get_capabilities
Function monitored_msr() still needs a stub to pass compilation when
VM_EVENT=n.

Signed-off-by: Penny Zheng <Penny.Zheng@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>

xen/arch/x86/hvm/Makefile

@@ -16,7 +16,7 @@ obj-y += io.o
 obj-y += ioreq.o
 obj-y += irq.o
 obj-y += mmio.o
-obj-y += monitor.o
+obj-$(CONFIG_VM_EVENT) += monitor.o
 obj-y += mtrr.o
 obj-y += nestedhvm.o
 obj-y += pmtimer.o

xen/arch/x86/hvm/svm/svm.c

@@ -297,6 +297,7 @@ void svm_intercept_msr(struct vcpu *v, uint32_t msr, int flags)
         __clear_bit(msr * 2 + 1, msr_bit);
 }
 
+#ifdef CONFIG_VM_EVENT
 static void cf_check svm_enable_msr_interception(struct domain *d, uint32_t msr)
 {
     struct vcpu *v;
@@ -304,6 +305,7 @@ static void cf_check svm_enable_msr_interception(struct domain *d, uint32_t msr)
     for_each_vcpu ( d, v )
         svm_intercept_msr(v, msr, MSR_INTERCEPT_WRITE);
 }
+#endif /* CONFIG_VM_EVENT */
 
 static void svm_save_dr(struct vcpu *v)
 {
@@ -824,6 +826,7 @@ static void cf_check svm_set_rdtsc_exiting(struct vcpu *v, bool enable)
     vmcb_set_general2_intercepts(vmcb, general2_intercepts);
 }
 
+#ifdef CONFIG_VM_EVENT
 static void cf_check svm_set_descriptor_access_exiting(
     struct vcpu *v, bool enable)
 {
@@ -841,6 +844,7 @@ static void cf_check svm_set_descriptor_access_exiting(
 
     vmcb_set_general1_intercepts(vmcb, general1_intercepts);
 }
+#endif /* CONFIG_VM_EVENT */
 
 static unsigned int cf_check svm_get_insn_bytes(struct vcpu *v, uint8_t *buf)
 {
@@ -2454,9 +2458,11 @@ static struct hvm_function_table __initdata_cf_clobber svm_function_table = {
     .fpu_dirty_intercept  = svm_fpu_dirty_intercept,
     .msr_read_intercept   = svm_msr_read_intercept,
     .msr_write_intercept  = svm_msr_write_intercept,
+#ifdef CONFIG_VM_EVENT
     .enable_msr_interception = svm_enable_msr_interception,
-    .set_rdtsc_exiting    = svm_set_rdtsc_exiting,
     .set_descriptor_access_exiting = svm_set_descriptor_access_exiting,
+#endif
+    .set_rdtsc_exiting    = svm_set_rdtsc_exiting,
     .get_insn_bytes       = svm_get_insn_bytes,
 
     .nhvm_vcpu_initialise = nsvm_vcpu_initialise,

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

@@ -1581,6 +1581,7 @@ static void cf_check vmx_set_rdtsc_exiting(struct vcpu *v, bool enable)
     vmx_vmcs_exit(v);
 }
 
+#ifdef CONFIG_VM_EVENT
 static void cf_check vmx_set_descriptor_access_exiting(
     struct vcpu *v, bool enable)
 {
@@ -1595,6 +1596,7 @@ static void cf_check vmx_set_descriptor_access_exiting(
     vmx_update_secondary_exec_control(v);
     vmx_vmcs_exit(v);
 }
+#endif /* CONFIG_VM_EVENT */
 
 static void cf_check vmx_init_hypercall_page(void *p)
 {
@@ -2474,6 +2476,7 @@ static void cf_check vmx_handle_eoi(uint8_t vector, int isr)
         printk_once(XENLOG_WARNING "EOI for %02x but SVI=%02x\n", vector, old_svi);
 }
 
+#ifdef CONFIG_VM_EVENT
 static void cf_check vmx_enable_msr_interception(struct domain *d, uint32_t msr)
 {
     struct vcpu *v;
@@ -2481,6 +2484,7 @@ static void cf_check vmx_enable_msr_interception(struct domain *d, uint32_t msr)
     for_each_vcpu ( d, v )
         vmx_set_msr_intercept(v, msr, VMX_MSR_W);
 }
+#endif /* CONFIG_VM_EVENT */
 
 #ifdef CONFIG_ALTP2M
 
@@ -2932,7 +2936,9 @@ static struct hvm_function_table __initdata_cf_clobber vmx_function_table = {
     .nhvm_domain_relinquish_resources = nvmx_domain_relinquish_resources,
     .update_vlapic_mode = vmx_vlapic_msr_changed,
     .nhvm_hap_walk_L1_p2m = nvmx_hap_walk_L1_p2m,
+#ifdef CONFIG_VM_EVENT
     .enable_msr_interception = vmx_enable_msr_interception,
+#endif
 #ifdef CONFIG_ALTP2M
     .altp2m_vcpu_update_p2m = vmx_vcpu_update_eptp,
     .altp2m_vcpu_update_vmfunc_ve = vmx_vcpu_update_vmfunc_ve,
@@ -3141,9 +3147,11 @@ const struct hvm_function_table * __init start_vmx(void)
 
     vmx_function_table.caps.singlestep = cpu_has_monitor_trap_flag;
 
+#ifdef CONFIG_VM_EVENT
     if ( cpu_has_vmx_dt_exiting )
         vmx_function_table.set_descriptor_access_exiting =
             vmx_set_descriptor_access_exiting;
+#endif
 
     /*
      * Do not enable EPT when (!cpu_has_vmx_pat), to prevent security hole
@@ -3214,8 +3222,10 @@ void __init vmx_fill_funcs(void)
     if ( !cpu_has_xen_ibt )
         return;
 
+#ifdef CONFIG_VM_EVENT
     vmx_function_table.set_descriptor_access_exiting =
         vmx_set_descriptor_access_exiting;
+#endif
 
     vmx_function_table.update_eoi_exit_bitmap = vmx_update_eoi_exit_bitmap;
     vmx_function_table.process_isr            = vmx_process_isr;

xen/arch/x86/include/asm/hvm/hvm.h

@@ -192,7 +192,11 @@ struct hvm_function_table {
     void (*handle_cd)(struct vcpu *v, unsigned long value);
     void (*set_info_guest)(struct vcpu *v);
     void (*set_rdtsc_exiting)(struct vcpu *v, bool enable);
+
+#ifdef CONFIG_VM_EVENT
     void (*set_descriptor_access_exiting)(struct vcpu *v, bool enable);
+    void (*enable_msr_interception)(struct domain *d, uint32_t msr);
+#endif
 
     /* Nested HVM */
     int (*nhvm_vcpu_initialise)(struct vcpu *v);
@@ -224,8 +228,6 @@ struct hvm_function_table {
                                 paddr_t *L1_gpa, unsigned int *page_order,
                                 uint8_t *p2m_acc, struct npfec npfec);
 
-    void (*enable_msr_interception)(struct domain *d, uint32_t msr);
-
 #ifdef CONFIG_ALTP2M
     /* Alternate p2m */
     void (*altp2m_vcpu_update_p2m)(struct vcpu *v);
@@ -435,11 +437,18 @@ static inline bool using_svm(void)
 
 #define hvm_long_mode_active(v) (!!((v)->arch.hvm.guest_efer & EFER_LMA))
 
+#ifdef CONFIG_VM_EVENT
 static inline bool hvm_has_set_descriptor_access_exiting(void)
 {
     return hvm_funcs.set_descriptor_access_exiting;
 }
 
+static inline void hvm_enable_msr_interception(struct domain *d, uint32_t msr)
+{
+    alternative_vcall(hvm_funcs.enable_msr_interception, d, msr);
+}
+#endif /* CONFIG_VM_EVENT */
+
 static inline void hvm_domain_creation_finished(struct domain *d)
 {
     if ( hvm_funcs.domain_creation_finished )
@@ -681,11 +690,6 @@ static inline int nhvm_hap_walk_L1_p2m(
         v, L2_gpa, L1_gpa, page_order, p2m_acc, npfec);
 }
 
-static inline void hvm_enable_msr_interception(struct domain *d, uint32_t msr)
-{
-    alternative_vcall(hvm_funcs.enable_msr_interception, d, msr);
-}
-
 static inline bool hvm_is_singlestep_supported(void)
 {
     return hvm_funcs.caps.singlestep;

xen/arch/x86/include/asm/monitor.h

@@ -71,6 +71,7 @@ int arch_monitor_domctl_op(struct domain *d, struct xen_domctl_monitor_op *mop)
     return rc;
 }
 
+#ifdef CONFIG_VM_EVENT
 static inline uint32_t arch_monitor_get_capabilities(struct domain *d)
 {
     uint32_t capabilities = 0;
@@ -102,6 +103,7 @@ static inline uint32_t arch_monitor_get_capabilities(struct domain *d)
 
     return capabilities;
 }
+#endif /* CONFIG_VM_EVENT */
 
 int arch_monitor_domctl_event(struct domain *d,
                               struct xen_domctl_monitor_op *mop);
@@ -123,7 +125,14 @@ static inline void arch_monitor_cleanup_domain(struct domain *d) {}
 
 #endif
 
+#ifdef CONFIG_VM_EVENT
 bool monitored_msr(const struct domain *d, u32 msr);
+#else
+static inline bool monitored_msr(const struct domain *d, u32 msr)
+{
+    return false;
+}
+#endif
 bool monitored_msr_onchangeonly(const struct domain *d, u32 msr);
 
 #endif /* __ASM_X86_MONITOR_H__ */