[PATCH v2 05/10] xen/x86: Use ASSERT instead of VIRTUAL_BUG_ON for phys_to_nid

[Wei Chen <wei.chen@xxxxxxx>]

VIRTUAL_BUG_ON is an empty macro used in phys_to_nid. This
results in two lines of error-checking code in phys_to_nid
that is not actually working and causing two compilation
errors:
1. error: "MAX_NUMNODES" undeclared (first use in this function).
   This is because in the common header file, "MAX_NUMNODES" is
   defined after the common header file includes the ARCH header
   file, where phys_to_nid has attempted to use "MAX_NUMNODES".
   This error was resolved when we moved the definition of
   "MAX_NUMNODES" to x86 ARCH header file. And we reserve the
   "MAX_NUMNODES" definition in common header file through a
   conditional compilation for some architectures that don't
   need to define "MAX_NUMNODES" in their ARCH header files.
2. error: wrong type argument to unary exclamation mark.
   This is because, the error-checking code contains !node_data[nid].
   But node_data is a data structure variable, it's not a pointer.

So, in this patch, we use ASSERT instead of VIRTUAL_BUG_ON to
enable the two lines of error-checking code. And fix the left
compilation errors by replacing !node_data[nid] to
!node_data[nid].node_spanned_pages.

Because when node_spanned_pages is 0, this node has no memory,
numa_scan_node will print warning message for such kind of nodes:
"Firmware Bug or mis-configured hardware?".

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v1 -> v2:
1. Use ASSERT to replace VIRTUAL_BUG_ON in phys_to_nid.
2. Adjust the conditional express for ASSERT.
3. Move MAX_NUMNODES from xen/numa.h to asm/numa.h for x86.
4. Use conditional macro to gate MAX_NUMNODES for other architectures.
---
 xen/arch/x86/include/asm/numa.h | 6 +++---
 xen/include/xen/numa.h          | 2 ++
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/include/asm/numa.h b/xen/arch/x86/include/asm/numa.h
index bada2c0bb9..1f268ce77d 100644
--- a/xen/arch/x86/include/asm/numa.h
+++ b/xen/arch/x86/include/asm/numa.h
@@ -4,6 +4,7 @@
 #include <xen/cpumask.h>
 
 #define NODES_SHIFT 6
+#define MAX_NUMNODES    (1 << NODES_SHIFT)
 
 typedef u8 nodeid_t;
 
@@ -26,7 +27,6 @@ extern int compute_hash_shift(struct node *nodes, int 
numnodes,
 extern nodeid_t pxm_to_node(unsigned int pxm);
 
 #define ZONE_ALIGN (1UL << (MAX_ORDER+PAGE_SHIFT))
-#define VIRTUAL_BUG_ON(x) 
 
 extern void numa_add_cpu(int cpu);
 extern void numa_init_array(void);
@@ -62,9 +62,9 @@ extern struct node_data node_data[];
 static inline __attribute__((pure)) nodeid_t phys_to_nid(paddr_t addr)
 { 
        nodeid_t nid;
-       VIRTUAL_BUG_ON((paddr_to_pdx(addr) >> memnode_shift) >= memnodemapsize);
+       ASSERT((paddr_to_pdx(addr) >> memnode_shift) < memnodemapsize);
        nid = memnodemap[paddr_to_pdx(addr) >> memnode_shift]; 
-       VIRTUAL_BUG_ON(nid >= MAX_NUMNODES || !node_data[nid]); 
+       ASSERT(nid < MAX_NUMNODES && node_data[nid].node_spanned_pages);
        return nid; 
 } 
 
diff --git a/xen/include/xen/numa.h b/xen/include/xen/numa.h
index 7aef1a88dc..91b25c5617 100644
--- a/xen/include/xen/numa.h
+++ b/xen/include/xen/numa.h
@@ -10,7 +10,9 @@
 #define NUMA_NO_NODE     0xFF
 #define NUMA_NO_DISTANCE 0xFF
 
+#ifndef MAX_NUMNODES
 #define MAX_NUMNODES    (1 << NODES_SHIFT)
+#endif
 
 #define vcpu_to_node(v) (cpu_to_node((v)->processor))
 
-- 
2.25.1