[Xen-devel] [PATCH] xenalyze: Unify record size checks

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

# HG changeset patch
# User George Dunlap <george.dunlap@xxxxxxxxxxxxx>
# Date 1299096700 0
# Node ID 3ef6e80faa4584837b55a58b8ffdd379e8ad0071
# Parent  cf2f412606b355508f25d9781f7b5fc8bf02f389
xenalyze: Unify record size checks

Unify record size checks, and tolerate an error in 3.4
that generates off-by-one records

Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

diff -r cf2f412606b3 -r 3ef6e80faa45 xenalyze.c
--- a/xenalyze.c        Wed Mar 02 20:11:40 2011 +0000
+++ b/xenalyze.c        Wed Mar 02 20:11:40 2011 +0000
@@ -1888,6 +1888,7 @@
 void error(enum error_level l, struct record_info *ri);
 void update_io_address(struct io_address ** list, unsigned int pa, int dir,
                        tsc_t arc_cycles, unsigned int va);
+int check_extra_words(struct record_info *ri, int expected_size, const char 
*record);
 
 void cpumask_init(cpu_mask_t *c) {
     *c = 0UL;
@@ -4260,15 +4261,8 @@
         unsigned long long val;
     } __attribute__((packed)) *r = (typeof(r))h->d;
 
-    int expected_extra=(sizeof(*r)/sizeof(unsigned int));
-
-    if(ri->extra_words != expected_extra )
-    {
-        fprintf(warn, "ERROR: msr_write extra_words %d, expected %d!\n",
-                ri->extra_words, expected_extra);
-        error(ERR_RECORD, ri);
+    if(check_extra_words(ri, sizeof(*r), "msr_write"))
         return;
-    } 
 
     h->inflight.msr.addr = r->addr;
     h->inflight.msr.val = r->val;
@@ -4312,15 +4306,8 @@
         unsigned long long val;
     } __attribute__((packed)) *r = (typeof(r))h->d;
 
-    int expected_extra=(sizeof(*r)/sizeof(unsigned int));
-
-    if(ri->extra_words != expected_extra)
-    {
-        fprintf(warn, "FATAL: msr_read extra_words %d, expected %d!\n",
-                ri->extra_words, expected_extra);
-        error(ERR_RECORD, ri);
+    if(check_extra_words(ri, sizeof(*r), "msr_read"))
         return;
-    } 
 
     h->inflight.msr.addr = r->addr;
     h->inflight.msr.val = r->val;
@@ -5014,7 +5001,6 @@
     d->runstate_tsc = tsc;
 }
 
-#define HAS_VMEXIT_32 1
 void hvm_vmexit_process(struct record_info *ri, struct hvm_data *h,
                         struct vcpu_data *v) {
     struct {
@@ -5030,16 +5016,16 @@
         };
     } *r;
 
-    if(ri->extra_words != 3
-       && ri->extra_words != 2
-        )
-    {
-        fprintf(warn, "FATAL: vmexit has unexpected extra words %d!\n",
-                ri->extra_words);
-        error(ERR_RECORD, ri);
-        return;
-    }
-    
+    if ( ri->event & TRC_64_FLAG )
+    {
+        if (check_extra_words(ri, sizeof(r->x64), "vmexit"))
+            return;
+    }
+    else
+    {
+        if (check_extra_words(ri, sizeof(r->x32), "vmexit"))
+            return;
+    }
 
     r = (typeof(r))ri->d;
 
@@ -7665,6 +7651,32 @@
     }
 }
 
+int check_extra_words(struct record_info *ri,
+                       int expected_size,
+                       const char *record)
+{
+    static int off_by_one = 0;
+    int expected_extra = expected_size / sizeof(unsigned int);
+    
+    if(ri->extra_words != expected_extra
+       && !(off_by_one && ri->extra_words == expected_extra + 1) )
+    {
+        if ( !off_by_one && ri->extra_words == expected_extra + 1 )
+        {
+            fprintf(warn, "Detected off-by-one bug; relaxing expectations\n");
+            off_by_one=1;
+        }
+        else {
+            fprintf(warn, "ERROR: %s extra_words %d, expected %d!\n",
+                    record,
+                    ri->extra_words, expected_extra);
+            error(ERR_RECORD, ri);
+            return 1;
+        }
+    } 
+    return 0;
+}
+
 void process_generic(struct record_info *ri) {
 
     error(ERR_STRICT, ri);

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