[PATCH 3/3] plugins/execlog: add address range matching

[Sven Schnelle <svens@stackframe.org>]

Allow to match memory ranges with the address matches. This
allows to give a range of adresses like '-dfilter=0-0x400'
which would only log memory accesses between 0 and 400.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 contrib/plugins/execlog.c | 73 ++++++++++++++++++++++++++++++---------
 1 file changed, 56 insertions(+), 17 deletions(-)

diff --git a/contrib/plugins/execlog.c b/contrib/plugins/execlog.c
index c89ebc08b6..b1b2a7baf1 100644
--- a/contrib/plugins/execlog.c
+++ b/contrib/plugins/execlog.c
@@ -44,6 +44,11 @@ static bool disas_assist;
 static GMutex add_reg_name_lock;
 static GPtrArray *all_reg_names;
 
+struct address_match {
+    uint64_t low;
+    uint64_t high;
+};
+
 static CPU *get_cpu(int vcpu_index)
 {
     CPU *c;
@@ -54,11 +59,12 @@ static CPU *get_cpu(int vcpu_index)
     return c;
 }
 
-static bool match_vaddr(uint64_t vaddr)
+static bool match_address_range(GArray *match, uint64_t vaddr)
 {
-    for (int i = 0; i < dmatches->len; i++) {
-        uint64_t v = g_array_index(dmatches, uint64_t, i);
-        if (v == vaddr) {
+    for (int i = 0; i < match->len; i++) {
+        struct address_match *m =
+            g_array_index(match, struct address_match *, i);
+        if (vaddr >= m->low && vaddr <= m->high) {
             return true;
         }
     }
@@ -74,9 +80,7 @@ static void vcpu_mem(unsigned int cpu_index, qemu_plugin_meminfo_t info,
     CPU *c = get_cpu(cpu_index);
     GString *s = c->last_exec;
 
-    /* Find vCPU in array */
-
-    if (dmatches && !match_vaddr(vaddr)) {
+    if (dmatches && !match_address_range(dmatches, vaddr)) {
         return;
     }
     c->log = true;
@@ -164,8 +168,10 @@ static void vcpu_insn_exec_only_regs(unsigned int cpu_index, void *udata)
             insn_check_regs(cpu);
         }
 
-        qemu_plugin_outs(cpu->last_exec->str);
-        qemu_plugin_outs("\n");
+        if (cpu->log) {
+            qemu_plugin_outs(cpu->last_exec->str);
+            qemu_plugin_outs("\n");
+        }
     }
 
     /* reset */
@@ -178,7 +184,7 @@ static void vcpu_insn_exec(unsigned int cpu_index, void *udata)
     CPU *cpu = get_cpu(cpu_index);
 
     /* Print previous instruction in cache */
-    if (cpu->last_exec->len) {
+    if (cpu->log && cpu->last_exec->len) {
         qemu_plugin_outs(cpu->last_exec->str);
         qemu_plugin_outs("\n");
     }
@@ -239,8 +245,7 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
         if (skip && amatches) {
             int j;
             for (j = 0; j < amatches->len && skip; j++) {
-                uint64_t v = g_array_index(amatches, uint64_t, j);
-                if (v == insn_vaddr) {
+                if (match_address_range(amatches, insn_vaddr)) {
                     skip = false;
                 }
             }
@@ -394,6 +399,17 @@ static void vcpu_init(qemu_plugin_id_t id, unsigned int vcpu_index)
     c->registers = registers_init(vcpu_index);
 }
 
+static void free_matches(GArray *matches)
+{
+    if (!matches) {
+        return;
+    }
+
+    for (int i = 0; i < matches->len; i++) {
+        g_free(g_array_index(matches, struct address_match *, i));
+    }
+}
+
 /**
  * On plugin exit, print last instruction in cache
  */
@@ -409,6 +425,9 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
         }
     }
     g_rw_lock_reader_unlock(&expand_array_lock);
+
+    free_matches(amatches);
+    free_matches(dmatches);
 }
 
 /* Add a match to the array of matches */
@@ -420,14 +439,34 @@ static void parse_insn_match(char *match)
     g_ptr_array_add(imatches, g_strdup(match));
 }
 
-static void parse_vaddr_match(GArray **matches, char *match)
+static void parse_vaddr_match(GArray **matches, char *token)
 {
-    uint64_t v = g_ascii_strtoull(match, NULL, 16);
+    uint64_t low, high;
+    gchar *endp;
 
-    if (!matches) {
-        *matches = g_array_new(false, true, sizeof(uint64_t));
+    low = g_ascii_strtoull(token, &endp, 16);
+    if (endp == token) {
+        fprintf(stderr, "Invalid address(range) specified: %s\n", token);
+        return;
+    }
+
+    if (*endp != '-') {
+        high = low;
+    } else {
+        high = g_ascii_strtoull(endp + 1, &endp, 16);
+        if (endp == token) {
+            fprintf(stderr, "Invalid address(range) specified: %s\n", token);
+            return;
+        }
+    }
+
+    if (!*matches) {
+        *matches = g_array_new(false, true, sizeof(struct address_match));
     }
-    g_array_append_val(*matches, v);
+    struct address_match *match = g_new(struct address_match, 1);
+    match->low = low;
+    match->high = high;
+    g_array_append_val(*matches, match);
 }
 
 /*
-- 
2.43.2