[PATCH v3 25/28] xen/domctl: avoid unreachable codes when both MGMT_HYPERCALLS and MEM_SHARING unset

[Penny Zheng <Penny.Zheng@xxxxxxx>]

The following functions have been referenced in places which is either guarded
with CONFIG_MGMT_HYPERCALLS or CONFIG_MEM_SHARING:
- arch_hvm_save
- arch_hvm_check
- arch_hvm_load
- hvm_save_size
- hvm_save
- hvm_load
- hvm_vmtrace_reset
So they shall be wrapped under OR relationship, otherwise they will become
unreachable codes when MGMT_HYPERCALLS=n && MEM_SHARING=n, and hence violating
Misra rule 2.1.
We move arch_hvm_save(), arch_hvm_check(), arch_hvm_load() and hvm_save_size()
nearer to the left functions, to avoid scattered #ifdef-wrapping.

Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
---
v2 -> v3
- new commit
---
 xen/arch/x86/hvm/save.c            | 154 +++++++++++++++--------------
 xen/arch/x86/hvm/vmx/vmx.c         |   4 +
 xen/arch/x86/include/asm/hvm/hvm.h |   4 +
 3 files changed, 86 insertions(+), 76 deletions(-)

diff --git a/xen/arch/x86/hvm/save.c b/xen/arch/x86/hvm/save.c
index 8ab6405706..47050e13b6 100644
--- a/xen/arch/x86/hvm/save.c
+++ b/xen/arch/x86/hvm/save.c
@@ -15,62 +15,6 @@
 
 #include <public/hvm/save.h>
 
-static void arch_hvm_save(struct domain *d, struct hvm_save_header *hdr)
-{
-    uint32_t eax, ebx, ecx, edx;
-
-    /* Save some CPUID bits */
-    cpuid(1, &eax, &ebx, &ecx, &edx);
-    hdr->cpuid = eax;
-
-    /* Save guest's preferred TSC. */
-    hdr->gtsc_khz = d->arch.tsc_khz;
-
-    /* Time when saving started */
-    d->arch.hvm.sync_tsc = rdtsc();
-}
-
-static int arch_hvm_check(const struct domain *d,
-                          const struct hvm_save_header *hdr)
-{
-    uint32_t eax, ebx, ecx, edx;
-
-    if ( hdr->magic != HVM_FILE_MAGIC )
-    {
-        printk(XENLOG_G_ERR "HVM%d restore: bad magic number %#"PRIx32"\n",
-               d->domain_id, hdr->magic);
-        return -EINVAL;
-    }
-
-    if ( hdr->version != HVM_FILE_VERSION )
-    {
-        printk(XENLOG_G_ERR "HVM%d restore: unsupported version %u\n",
-               d->domain_id, hdr->version);
-        return -EINVAL;
-    }
-
-    cpuid(1, &eax, &ebx, &ecx, &edx);
-    /* CPUs ought to match but with feature-masking they might not */
-    if ( (hdr->cpuid & ~0x0fUL) != (eax & ~0x0fUL) )
-        printk(XENLOG_G_INFO "HVM%d restore: VM saved on one CPU "
-               "(%#"PRIx32") and restored on another (%#"PRIx32").\n",
-               d->domain_id, hdr->cpuid, eax);
-
-    return 0;
-}
-
-static void arch_hvm_load(struct domain *d, const struct hvm_save_header *hdr)
-{
-    /* Restore guest's preferred TSC frequency. */
-    if ( hdr->gtsc_khz )
-        d->arch.tsc_khz = hdr->gtsc_khz;
-    if ( d->arch.vtsc )
-        hvm_set_rdtsc_exiting(d, 1);
-
-    /* Time when restore started  */
-    d->arch.hvm.sync_tsc = rdtsc();
-}
-
 /* List of handlers for various HVM save and restore types */
 static struct {
     hvm_save_handler save;
@@ -101,26 +45,6 @@ void __init hvm_register_savevm(uint16_t typecode,
     hvm_sr_handlers[typecode].kind = kind;
 }
 
-size_t hvm_save_size(struct domain *d)
-{
-    struct vcpu *v;
-    size_t sz;
-    int i;
-
-    /* Basic overhead for header and footer */
-    sz = (2 * sizeof (struct hvm_save_descriptor)) + HVM_SAVE_LENGTH(HEADER);
-
-    /* Plus space for each thing we will be saving */
-    for ( i = 0; i <= HVM_SAVE_CODE_MAX; i++ )
-        if ( hvm_sr_handlers[i].kind == HVMSR_PER_VCPU )
-            for_each_vcpu(d, v)
-                sz += hvm_sr_handlers[i].size;
-        else
-            sz += hvm_sr_handlers[i].size;
-
-    return sz;
-}
-
 /*
  * Extract a single instance of a save record, by marshalling all records of
  * that type and copying out the one we need.
@@ -196,6 +120,83 @@ int hvm_save_one(struct domain *d, unsigned int typecode, 
unsigned int instance,
     return rv;
 }
 
+#if defined(CONFIG_MGMT_HYPERCALLS) || defined(CONFIG_MEM_SHARING)
+static void arch_hvm_save(struct domain *d, struct hvm_save_header *hdr)
+{
+    uint32_t eax, ebx, ecx, edx;
+
+    /* Save some CPUID bits */
+    cpuid(1, &eax, &ebx, &ecx, &edx);
+    hdr->cpuid = eax;
+
+    /* Save guest's preferred TSC. */
+    hdr->gtsc_khz = d->arch.tsc_khz;
+
+    /* Time when saving started */
+    d->arch.hvm.sync_tsc = rdtsc();
+}
+
+static int arch_hvm_check(const struct domain *d,
+                          const struct hvm_save_header *hdr)
+{
+    uint32_t eax, ebx, ecx, edx;
+
+    if ( hdr->magic != HVM_FILE_MAGIC )
+    {
+        printk(XENLOG_G_ERR "HVM%d restore: bad magic number %#"PRIx32"\n",
+               d->domain_id, hdr->magic);
+        return -EINVAL;
+    }
+
+    if ( hdr->version != HVM_FILE_VERSION )
+    {
+        printk(XENLOG_G_ERR "HVM%d restore: unsupported version %u\n",
+               d->domain_id, hdr->version);
+        return -EINVAL;
+    }
+
+    cpuid(1, &eax, &ebx, &ecx, &edx);
+    /* CPUs ought to match but with feature-masking they might not */
+    if ( (hdr->cpuid & ~0x0fUL) != (eax & ~0x0fUL) )
+        printk(XENLOG_G_INFO "HVM%d restore: VM saved on one CPU "
+               "(%#"PRIx32") and restored on another (%#"PRIx32").\n",
+               d->domain_id, hdr->cpuid, eax);
+
+    return 0;
+}
+
+static void arch_hvm_load(struct domain *d, const struct hvm_save_header *hdr)
+{
+    /* Restore guest's preferred TSC frequency. */
+    if ( hdr->gtsc_khz )
+        d->arch.tsc_khz = hdr->gtsc_khz;
+    if ( d->arch.vtsc )
+        hvm_set_rdtsc_exiting(d, 1);
+
+    /* Time when restore started  */
+    d->arch.hvm.sync_tsc = rdtsc();
+}
+
+size_t hvm_save_size(struct domain *d)
+{
+    struct vcpu *v;
+    size_t sz;
+    unsigned int i;
+
+    /* Basic overhead for header and footer */
+    sz = (2 * sizeof (struct hvm_save_descriptor)) + HVM_SAVE_LENGTH(HEADER);
+
+    /* Plus space for each thing we will be saving */
+    for ( i = 0; i <= HVM_SAVE_CODE_MAX; i++ )
+        if ( hvm_sr_handlers[i].kind == HVMSR_PER_VCPU )
+            for_each_vcpu(d, v)
+                sz += hvm_sr_handlers[i].size;
+        else
+            sz += hvm_sr_handlers[i].size;
+
+    return sz;
+}
+
 int hvm_save(struct domain *d, hvm_domain_context_t *h)
 {
     char *c;
@@ -390,6 +391,7 @@ int hvm_load(struct domain *d, bool real, 
hvm_domain_context_t *h)
 
     /* Not reached */
 }
+#endif /* CONFIG_MGMT_HYPERCALLS || CONFIG_MEM_SHARING */
 
 int _hvm_init_entry(struct hvm_domain_context *h, uint16_t tc, uint16_t inst,
                     uint32_t len)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 1996e139a0..4394990131 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2701,6 +2701,7 @@ static int cf_check vmtrace_output_position(struct vcpu 
*v, uint64_t *pos)
     return v->arch.hvm.vmx.ipt_active;
 }
 
+#if defined(CONFIG_MGMT_HYPERCALLS) || defined(CONFIG_MEM_SHARING)
 static int cf_check vmtrace_reset(struct vcpu *v)
 {
     if ( !v->arch.hvm.vmx.ipt_active )
@@ -2710,6 +2711,7 @@ static int cf_check vmtrace_reset(struct vcpu *v)
     v->arch.msrs->rtit.status = 0;
     return 0;
 }
+#endif /* CONFIG_MGMT_HYPERCALLS || CONFIG_MEM_SHARING */
 
 static uint64_t cf_check vmx_get_reg(struct vcpu *v, unsigned int reg)
 {
@@ -2888,7 +2890,9 @@ static struct hvm_function_table __initdata_cf_clobber 
vmx_function_table = {
     .vmtrace_output_position = vmtrace_output_position,
     .vmtrace_set_option = vmtrace_set_option,
     .vmtrace_get_option = vmtrace_get_option,
+#if defined(CONFIG_MGMT_HYPERCALLS) || defined(CONFIG_MEM_SHARING)
     .vmtrace_reset = vmtrace_reset,
+#endif
 
     .get_reg = vmx_get_reg,
     .set_reg = vmx_set_reg,
diff --git a/xen/arch/x86/include/asm/hvm/hvm.h 
b/xen/arch/x86/include/asm/hvm/hvm.h
index 473cf24b83..9d6cb42d48 100644
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -240,7 +240,9 @@ struct hvm_function_table {
     int (*vmtrace_output_position)(struct vcpu *v, uint64_t *pos);
     int (*vmtrace_set_option)(struct vcpu *v, uint64_t key, uint64_t value);
     int (*vmtrace_get_option)(struct vcpu *v, uint64_t key, uint64_t *value);
+#if defined(CONFIG_MGMT_HYPERCALLS) || defined(CONFIG_MEM_SHARING)
     int (*vmtrace_reset)(struct vcpu *v);
+#endif
 
     uint64_t (*get_reg)(struct vcpu *v, unsigned int reg);
     void (*set_reg)(struct vcpu *v, unsigned int reg, uint64_t val);
@@ -775,6 +777,7 @@ static inline int hvm_vmtrace_get_option(
     return -EOPNOTSUPP;
 }
 
+#if defined(CONFIG_MGMT_HYPERCALLS) || defined(CONFIG_MEM_SHARING)
 static inline int hvm_vmtrace_reset(struct vcpu *v)
 {
     if ( hvm_funcs.vmtrace_reset )
@@ -782,6 +785,7 @@ static inline int hvm_vmtrace_reset(struct vcpu *v)
 
     return -EOPNOTSUPP;
 }
+#endif /* CONFIG_MGMT_HYPERCALLS || CONFIG_MEM_SHARING */
 
 /*
  * Accessors for registers which have per-guest-type or per-vendor locations
-- 
2.34.1