xen/memory: Remove tail padding from TRC_MEM_* records

Four TRC_MEM_* records supply custom structures with tail padding, leaking
stack rubble into the trace buffer.  Three of the records were fine in 32-bit
builds of Xen, due to the relaxed alignment of 64-bit integers, but
POD_SUPERPAGE_SPLITER was broken right from the outset.

We could pack the datastructures to remove the padding, but xentrace_format
has no way of rendering the upper half of a 16-bit field.  Instead, expand all
16-bit fields to 32-bit.

For POD_SUPERPAGE_SPLINTER, introduce an order field as it is relevant
information, and to match DECREASE_RESERVATION, and so it doesn't require a
__packed attribute to drop tail padding.

Update xenalyze's structures to match, and introduce xentrace_format rendering
which was absent previously.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>

tools/xentrace/formats

@@ -136,6 +136,10 @@
 0x0010f001  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  page_grant_map      [ domid = %(1)d ]
 0x0010f002  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  page_grant_unmap    [ domid = %(1)d ]
 0x0010f003  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  page_grant_transfer [ domid = %(1)d ]
+0x0010f005  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  decrease_reservation   [ d%(3)d gfn 0x%(2)08x%(1)08x, order %(4)u ]
+0x0010f010  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  pod_populate           [ d%(5)d gfn 0x%(2)08x%(1)08x => mfn 0x%(4)08x%(3)08x, order %(6)u ]
+0x0010f011  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  pod_zero_reclaim       [ d%(5)d gfn 0x%(2)08x%(1)08x => mfn 0x%(4)08x%(3)08x, order %(6)u ]
+0x0010f012  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  pod_superpage_splinter [ d%(3)d gfn 0x%(2)08x%(1)08x, order %(4)u ]
 
 0x00201001  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  hypercall  [ eip = 0x%(1)08x, eax = 0x%(2)08x ]
 0x00201101  CPU%(cpu)d  %(tsc)d (+%(reltsc)8d)  hypercall  [ rip = 0x%(2)08x%(1)08x, eax = 0x%(3)08x ]

tools/xentrace/xenalyze.c

@@ -8121,7 +8121,7 @@ void mem_pod_zero_reclaim_process(struct pcpu_info *p)
 
     struct {
         uint64_t gfn, mfn;
-        int d:16,order:16;
+        uint32_t d, order;
     } *r = (typeof(r))ri->d;
 
     if ( v && v->hvm.vmexit_valid )
@@ -8171,7 +8171,7 @@ void mem_pod_populate_process(struct pcpu_info *p)
 
     struct {
         uint64_t gfn, mfn;
-        int d:16,order:16;
+        uint32_t d, order;
     } *r = (typeof(r))ri->d;
 
     if ( opt.dump_all )
@@ -8204,14 +8204,14 @@ void mem_pod_superpage_splinter_process(struct pcpu_info *p)
 
     struct {
         uint64_t gfn;
-        int d:16;
+        uint32_t d, order;
     } *r = (typeof(r))ri->d;
 
     if ( opt.dump_all )
     {
-        printf(" %s pod_spage_splinter d%d g %llx\n",
+        printf(" %s pod_spage_splinter d%d o%d g %"PRIx64"\n",
                ri->dump_header,
-               r->d, (unsigned long long)r->gfn);
+               r->d, r->order, r->gfn);
     }
 }
 
@@ -8255,7 +8255,7 @@ void mem_decrease_reservation_process(struct pcpu_info *p)
 
     struct {
         uint64_t gfn;
-        int d:16,order:16;
+        uint32_t d, order;
     } *r = (typeof(r))ri->d;
 
     if ( opt.dump_all )

xen/arch/x86/mm/p2m-pod.c

@@ -868,8 +868,8 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m, gfn_t gfn)
     if ( tb_init_done )
     {
         struct {
-            u64 gfn, mfn;
-            int d:16,order:16;
+            uint64_t gfn, mfn;
+            uint32_t d, order;
         } t;
 
         t.gfn = gfn_x(gfn);
@@ -1036,8 +1036,8 @@ p2m_pod_zero_check(struct p2m_domain *p2m, const gfn_t *gfns, unsigned int count
             if ( tb_init_done )
             {
                 struct {
-                    u64 gfn, mfn;
-                    int d:16,order:16;
+                    uint64_t gfn, mfn;
+                    uint32_t d, order;
                 } t;
 
                 t.gfn = gfn_x(gfns[i]);
@@ -1276,8 +1276,8 @@ p2m_pod_demand_populate(struct p2m_domain *p2m, gfn_t gfn,
     if ( tb_init_done )
     {
         struct {
-            u64 gfn, mfn;
-            int d:16,order:16;
+            uint64_t gfn, mfn;
+            uint32_t d, order;
         } t;
 
         t.gfn = gfn_x(gfn);
@@ -1322,12 +1322,13 @@ remap_and_retry:
     if ( tb_init_done )
     {
         struct {
-            u64 gfn;
-            int d:16;
+            uint64_t gfn;
+            uint32_t d, order;
         } t;
 
         t.gfn = gfn_x(gfn);
         t.d = d->domain_id;
+        t.order = order;
 
         __trace_var(TRC_MEM_POD_SUPERPAGE_SPLINTER, 0, sizeof(t), &t);
     }

xen/common/memory.c

@@ -474,8 +474,8 @@ static void decrease_reservation(struct memop_args *a)
         if ( tb_init_done )
         {
             struct {
-                u64 gfn;
-                int d:16,order:16;
+                uint64_t gfn;
+                uint32_t d, order;
             } t;
 
             t.gfn = gmfn;