plugins: Use DisasContextBase for qemu_plugin_insn_haddr

We can delay the computation of haddr until the plugin
actually requests it.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

accel/tcg/plugin-gen.c

@@ -319,9 +319,6 @@ bool plugin_gen_tb_start(CPUState *cpu, const DisasContextBase *db)
         ret = true;
 
         ptb->vaddr = db->pc_first;
-        ptb->vaddr2 = -1;
-        ptb->haddr1 = db->host_addr[0];
-        ptb->haddr2 = NULL;
         ptb->mem_helper = false;
 
         tcg_gen_plugin_cb(PLUGIN_GEN_FROM_TB);
@@ -363,23 +360,6 @@ void plugin_gen_insn_start(CPUState *cpu, const DisasContextBase *db)
     pc = db->pc_next;
     insn->vaddr = pc;
 
-    /*
-     * Detect page crossing to get the new host address.
-     * Note that we skip this when haddr1 == NULL, e.g. when we're
-     * fetching instructions from a region not backed by RAM.
-     */
-    if (ptb->haddr1 == NULL) {
-        insn->haddr = NULL;
-    } else if (is_same_page(db, db->pc_next)) {
-        insn->haddr = ptb->haddr1 + pc - ptb->vaddr;
-    } else {
-        if (ptb->vaddr2 == -1) {
-            ptb->vaddr2 = TARGET_PAGE_ALIGN(db->pc_first);
-            get_page_addr_code_hostp(cpu_env(cpu), ptb->vaddr2, &ptb->haddr2);
-        }
-        insn->haddr = ptb->haddr2 + pc - ptb->vaddr2;
-    }
-
     tcg_gen_plugin_cb(PLUGIN_GEN_FROM_INSN);
 }
 

include/qemu/plugin.h

@@ -99,7 +99,6 @@ struct qemu_plugin_dyn_cb {
 /* Internal context for instrumenting an instruction */
 struct qemu_plugin_insn {
     uint64_t vaddr;
-    void *haddr;
     GArray *insn_cbs;
     GArray *mem_cbs;
     uint8_t len;
@@ -120,9 +119,6 @@ struct qemu_plugin_tb {
     GPtrArray *insns;
     size_t n;
     uint64_t vaddr;
-    uint64_t vaddr2;
-    void *haddr1;
-    void *haddr2;
 
     /* if set, the TB calls helpers that might access guest memory */
     bool mem_helper;

plugins/api.c

@@ -242,7 +242,30 @@ uint64_t qemu_plugin_insn_vaddr(const struct qemu_plugin_insn *insn)
 
 void *qemu_plugin_insn_haddr(const struct qemu_plugin_insn *insn)
 {
-    return insn->haddr;
+    const DisasContextBase *db = tcg_ctx->plugin_db;
+    vaddr page0_last = db->pc_first | ~TARGET_PAGE_MASK;
+
+    if (db->fake_insn) {
+        return NULL;
+    }
+
+    /*
+     * ??? The return value is not intended for use of host memory,
+     * but as a proxy for address space and physical address.
+     * Thus we are only interested in the first byte and do not
+     * care about spanning pages.
+     */
+    if (insn->vaddr <= page0_last) {
+        if (db->host_addr[0] == NULL) {
+            return NULL;
+        }
+        return db->host_addr[0] + insn->vaddr - db->pc_first;
+    } else {
+        if (db->host_addr[1] == NULL) {
+            return NULL;
+        }
+        return db->host_addr[1] + insn->vaddr - (page0_last + 1);
+    }
 }
 
 char *qemu_plugin_insn_disas(const struct qemu_plugin_insn *insn)