final updates for 9.0 (testing, gdbstub):

- fix the over rebuilding of test VMs
   - support Xfer:siginfo:read in gdbstub
   - fix double close() in gdbstub
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Merge tag 'pull-maintainer-final-130324-1' of https://gitlab.com/stsquad/qemu into staging

final updates for 9.0 (testing, gdbstub):

  - fix the over rebuilding of test VMs
  - support Xfer:siginfo:read in gdbstub
  - fix double close() in gdbstub

# -----BEGIN PGP SIGNATURE-----
#
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# KkSw9wf+K+3kJYaZ2unEFku3Y6f4Z9XkrZCsFQFVNIJQgpYVc6peQyLUB1pZwzZc
# yoQhmTIgej16iRZc7gEcJhFl2zlX2vulE/m+wiaR0Chv3E2r510AGn4aWl+GLB9+
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# =BOWW
# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 13 Mar 2024 11:45:01 GMT
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* tag 'pull-maintainer-final-130324-1' of https://gitlab.com/stsquad/qemu:
  gdbstub: Fix double close() of the follow-fork-mode socket
  tests/tcg: Add multiarch test for Xfer:siginfo:read stub
  gdbstub: Add Xfer:siginfo:read stub
  gdbstub: Save target's siginfo
  linux-user: Move tswap_siginfo out of target code
  gdbstub: Rename back gdb_handlesig
  tests/vm: ensure we build everything by default

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

bsd-user/main.c

@@ -606,7 +606,7 @@ int main(int argc, char **argv)
 
     if (gdbstub) {
         gdbserver_start(gdbstub);
-        gdb_handlesig(cpu, 0);
+        gdb_handlesig(cpu, 0, NULL, NULL, 0);
     }
     cpu_loop(env);
     /* never exits */

bsd-user/signal.c

@@ -27,6 +27,9 @@
 #include "hw/core/tcg-cpu-ops.h"
 #include "host-signal.h"
 
+/* target_siginfo_t must fit in gdbstub's siginfo save area. */
+QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH);
+
 static struct target_sigaction sigact_table[TARGET_NSIG];
 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc);
 static void target_to_host_sigset_internal(sigset_t *d,
@@ -889,7 +892,7 @@ static void handle_pending_signal(CPUArchState *env, int sig,
 
     k->pending = 0;
 
-    sig = gdb_handlesig(cpu, sig);
+    sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info));
     if (!sig) {
         sa = NULL;
         handler = TARGET_SIG_IGN;

gdbstub/gdbstub.c

@@ -1664,6 +1664,8 @@ static void handle_query_supported(GArray *params, void *user_ctx)
         g_string_append(gdbserver_state.str_buf, ";qXfer:auxv:read+");
     }
     g_string_append(gdbserver_state.str_buf, ";QCatchSyscalls+");
+
+    g_string_append(gdbserver_state.str_buf, ";qXfer:siginfo:read+");
 #endif
     g_string_append(gdbserver_state.str_buf, ";qXfer:exec-file:read+");
 #endif
@@ -1818,6 +1820,12 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = {
         .cmd_startswith = 1,
         .schema = "l,l0"
     },
+    {
+        .handler = gdb_handle_query_xfer_siginfo,
+        .cmd = "Xfer:siginfo:read::",
+        .cmd_startswith = 1,
+        .schema = "l,l0"
+     },
 #endif
     {
         .handler = gdb_handle_query_xfer_exec_file,

gdbstub/internals.h

@@ -190,6 +190,7 @@ typedef union GdbCmdVariant {
 void gdb_handle_query_rcmd(GArray *params, void *user_ctx); /* softmmu */
 void gdb_handle_query_offsets(GArray *params, void *user_ctx); /* user */
 void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx); /*user */
+void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx); /*user */
 void gdb_handle_v_file_open(GArray *params, void *user_ctx); /* user */
 void gdb_handle_v_file_close(GArray *params, void *user_ctx); /* user */
 void gdb_handle_v_file_pread(GArray *params, void *user_ctx); /* user */

gdbstub/user.c

@@ -95,6 +95,8 @@ typedef struct {
     enum GDBForkState fork_state;
     int fork_sockets[2];
     pid_t fork_peer_pid, fork_peer_tid;
+    uint8_t siginfo[MAX_SIGINFO_LENGTH];
+    unsigned long siginfo_len;
 } GDBUserState;
 
 static GDBUserState gdbserver_user_state;
@@ -190,7 +192,8 @@ void gdb_qemu_exit(int code)
     exit(code);
 }
 
-int gdb_handlesig_reason(CPUState *cpu, int sig, const char *reason)
+int gdb_handlesig(CPUState *cpu, int sig, const char *reason, void *siginfo,
+                  int siginfo_len)
 {
     char buf[256];
     int n;
@@ -199,6 +202,18 @@ int gdb_handlesig_reason(CPUState *cpu, int sig, const char *reason)
         return sig;
     }
 
+    if (siginfo) {
+        /*
+         * Save target-specific siginfo.
+         *
+         * siginfo size, i.e. siginfo_len, is asserted at compile-time to fit in
+         * gdbserver_user_state.siginfo, usually in the source file calling
+         * gdb_handlesig. See, for instance, {linux,bsd}-user/signal.c.
+         */
+        memcpy(gdbserver_user_state.siginfo, siginfo, siginfo_len);
+        gdbserver_user_state.siginfo_len = siginfo_len;
+    }
+
     /* disable single step if it was enabled */
     cpu_single_step(cpu, 0);
     tb_flush(cpu);
@@ -502,6 +517,7 @@ void gdbserver_fork_end(CPUState *cpu, pid_t pid)
         switch (gdbserver_user_state.fork_state) {
         case GDB_FORK_ENABLED:
             if (gdbserver_user_state.running_state) {
+                close(fd);
                 return;
             }
             QEMU_FALLTHROUGH;
@@ -527,7 +543,6 @@ void gdbserver_fork_end(CPUState *cpu, pid_t pid)
                 gdbserver_user_state.fork_state = GDB_FORK_ACTIVE;
                 break;
             case GDB_FORK_ENABLE:
-                close(fd);
                 gdbserver_user_state.fork_state = GDB_FORK_ENABLED;
                 break;
             case GDB_FORK_DISABLE:
@@ -542,7 +557,6 @@ void gdbserver_fork_end(CPUState *cpu, pid_t pid)
             if (write(fd, &b, 1) != 1) {
                 goto fail;
             }
-            close(fd);
             gdbserver_user_state.fork_state = GDB_FORK_ENABLED;
             break;
         case GDB_FORK_DISABLING:
@@ -746,7 +760,7 @@ void gdb_breakpoint_remove_all(CPUState *cs)
 void gdb_syscall_handling(const char *syscall_packet)
 {
     gdb_put_packet(syscall_packet);
-    gdb_handlesig(gdbserver_state.c_cpu, 0);
+    gdb_handlesig(gdbserver_state.c_cpu, 0, NULL, NULL, 0);
 }
 
 static bool should_catch_syscall(int num)
@@ -764,7 +778,7 @@ void gdb_syscall_entry(CPUState *cs, int num)
 {
     if (should_catch_syscall(num)) {
         g_autofree char *reason = g_strdup_printf("syscall_entry:%x;", num);
-        gdb_handlesig_reason(cs, gdb_target_sigtrap(), reason);
+        gdb_handlesig(cs, gdb_target_sigtrap(), reason, NULL, 0);
     }
 }
 
@@ -772,7 +786,7 @@ void gdb_syscall_return(CPUState *cs, int num)
 {
     if (should_catch_syscall(num)) {
         g_autofree char *reason = g_strdup_printf("syscall_return:%x;", num);
-        gdb_handlesig_reason(cs, gdb_target_sigtrap(), reason);
+        gdb_handlesig(cs, gdb_target_sigtrap(), reason, NULL, 0);
     }
 }
 
@@ -837,3 +851,26 @@ void gdb_handle_set_catch_syscalls(GArray *params, void *user_ctx)
 err:
     gdb_put_packet("E00");
 }
+
+void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx)
+{
+    unsigned long offset, len;
+    uint8_t *siginfo_offset;
+
+    offset = get_param(params, 0)->val_ul;
+    len = get_param(params, 1)->val_ul;
+
+    if (offset + len > gdbserver_user_state.siginfo_len) {
+        /* Invalid offset and/or requested length. */
+        gdb_put_packet("E01");
+        return;
+    }
+
+    siginfo_offset = (uint8_t *)gdbserver_user_state.siginfo + offset;
+
+    /* Reply */
+    g_string_assign(gdbserver_state.str_buf, "l");
+    gdb_memtox(gdbserver_state.str_buf, (const char *)siginfo_offset, len);
+    gdb_put_packet_binary(gdbserver_state.str_buf->str,
+                          gdbserver_state.str_buf->len, true);
+}

include/gdbstub/user.h

@@ -9,11 +9,15 @@
 #ifndef GDBSTUB_USER_H
 #define GDBSTUB_USER_H
 
+#define MAX_SIGINFO_LENGTH 128
+
 /**
- * gdb_handlesig_reason() - yield control to gdb
+ * gdb_handlesig() - yield control to gdb
  * @cpu: CPU
  * @sig: if non-zero, the signal number which caused us to stop
  * @reason: stop reason for stop reply packet or NULL
+ * @siginfo: target-specific siginfo struct
+ * @siginfo_len: target-specific siginfo struct length
  *
  * This function yields control to gdb, when a user-mode-only target
  * needs to stop execution. If @sig is non-zero, then we will send a
@@ -25,18 +29,7 @@
  * or 0 if no signal should be delivered, ie the signal that caused
  * us to stop should be ignored.
  */
-int gdb_handlesig_reason(CPUState *, int, const char *);
-
-/**
- * gdb_handlesig() - yield control to gdb
- * @cpu CPU
- * @sig: if non-zero, the signal number which caused us to stop
- * @see gdb_handlesig_reason()
- */
-static inline int gdb_handlesig(CPUState *cpu, int sig)
-{
-    return gdb_handlesig_reason(cpu, sig, NULL);
-}
+int gdb_handlesig(CPUState *, int, const char *, void *, int);
 
 /**
  * gdb_signalled() - inform remote gdb of sig exit

linux-user/aarch64/signal.c

@@ -670,7 +670,7 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
     aarch64_set_svcr(env, 0, R_SVCR_SM_MASK | R_SVCR_ZA_MASK);
 
     if (info) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
         env->xregs[1] = frame_addr + offsetof(struct target_rt_sigframe, info);
         env->xregs[2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
     }

linux-user/alpha/signal.c

@@ -173,7 +173,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     __put_user(0, &frame->uc.tuc_flags);
     __put_user(0, &frame->uc.tuc_link);

linux-user/arm/signal.c

@@ -357,7 +357,7 @@ void setup_rt_frame(int usig, struct target_sigaction *ka,
 
     info_addr = frame_addr + offsetof(struct rt_sigframe, info);
     uc_addr = frame_addr + offsetof(struct rt_sigframe, sig.uc);
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     setup_sigframe(&frame->sig.uc, set, env);
 

linux-user/hexagon/signal.c

@@ -162,7 +162,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     setup_ucontext(&frame->uc, env, set);
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
     /*
      * The on-stack signal trampoline is no longer executed;
      * however, the libgcc signal frame unwinding code checks

linux-user/hppa/signal.c

@@ -127,7 +127,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
     frame->uc.tuc_flags = 0;
     frame->uc.tuc_link = 0;
 

linux-user/i386/signal.c

@@ -430,7 +430,7 @@ void setup_frame(int sig, struct target_sigaction *ka,
     setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
             frame_addr + offsetof(struct sigframe, fpstate));
 
-    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 1; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->extramask[i - 1]);
     }
 
@@ -490,7 +490,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     __put_user(addr, &frame->puc);
 #endif
     if (ka->sa_flags & TARGET_SA_SIGINFO) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
     }
 
     /* Create the ucontext.  */
@@ -504,7 +504,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
             set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
 
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
     }
 

linux-user/loongarch64/signal.c

@@ -376,7 +376,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         extctx.end.haddr = (void *)frame + (extctx.end.gaddr - frame_addr);
     }
 
-    tswap_siginfo(&frame->rs_info, info);
+    frame->rs_info = *info;
 
     __put_user(0, &frame->rs_uc.tuc_flags);
     __put_user(0, &frame->rs_uc.tuc_link);

linux-user/m68k/signal.c

@@ -295,7 +295,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     uc_addr = frame_addr + offsetof(struct target_rt_sigframe, uc);
     __put_user(uc_addr, &frame->puc);
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create the ucontext */
 
@@ -307,7 +307,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (err)
         goto give_sigsegv;
 
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
     }
 

linux-user/main.c

@@ -1018,7 +1018,7 @@ int main(int argc, char **argv, char **envp)
                     gdbstub);
             exit(EXIT_FAILURE);
         }
-        gdb_handlesig(cpu, 0);
+        gdb_handlesig(cpu, 0, NULL, NULL, 0);
     }
 
 #ifdef CONFIG_SEMIHOSTING

linux-user/microblaze/signal.c

@@ -147,7 +147,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         return;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     __put_user(0, &frame->uc.tuc_flags);
     __put_user(0, &frame->uc.tuc_link);

linux-user/mips/signal.c

@@ -303,7 +303,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->rs_info, info);
+    frame->rs_info = *info;
 
     __put_user(0, &frame->rs_uc.tuc_flags);
     __put_user(0, &frame->rs_uc.tuc_link);
@@ -311,7 +311,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     setup_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]);
     }
 

linux-user/nios2/signal.c

@@ -157,7 +157,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         return;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create the ucontext.  */
     __put_user(0, &frame->uc.tuc_flags);

linux-user/openrisc/signal.c

@@ -103,7 +103,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     if (ka->sa_flags & SA_SIGINFO) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
     }
 
     __put_user(0, &frame->uc.tuc_flags);

linux-user/ppc/signal.c

@@ -493,7 +493,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
         goto sigsegv;
 
-    tswap_siginfo(&rt_sf->info, info);
+    rt_sf->info = *info;
 
     __put_user(0, &rt_sf->uc.tuc_flags);
     __put_user(0, &rt_sf->uc.tuc_link);
@@ -502,7 +502,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
                &rt_sf->uc.tuc_regs);
 #endif
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
     }
 

linux-user/riscv/signal.c

@@ -125,7 +125,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     setup_ucontext(&frame->uc, env, set);
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     env->pc = ka->_sa_handler;
     env->gpr[xSP] = frame_addr;

linux-user/s390x/signal.c

@@ -267,7 +267,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     /* Create siginfo on the signal stack. */
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create ucontext on the signal stack. */
     uc_flags = 0;

linux-user/sh4/signal.c

@@ -233,7 +233,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create the ucontext.  */
     __put_user(0, &frame->uc.tuc_flags);

linux-user/signal-common.h

@@ -43,8 +43,6 @@ void host_to_target_sigset_internal(target_sigset_t *d,
                                     const sigset_t *s);
 void target_to_host_sigset_internal(sigset_t *d,
                                     const target_sigset_t *s);
-void tswap_siginfo(target_siginfo_t *tinfo,
-                   const target_siginfo_t *info);
 void set_sigmask(const sigset_t *set);
 void force_sig(int sig);
 void force_sigsegv(int oldsig);

linux-user/signal.c

@@ -34,6 +34,9 @@
 #include "user/safe-syscall.h"
 #include "tcg/tcg.h"
 
+/* target_siginfo_t must fit in gdbstub's siginfo save area. */
+QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH);
+
 static struct target_sigaction sigact_table[TARGET_NSIG];
 
 static void host_signal_handler(int host_signum, siginfo_t *info,
@@ -409,8 +412,8 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
     tinfo->si_code = deposit32(si_code, 16, 16, si_type);
 }
 
-void tswap_siginfo(target_siginfo_t *tinfo,
-                   const target_siginfo_t *info)
+static void tswap_siginfo(target_siginfo_t *tinfo,
+                          const target_siginfo_t *info)
 {
     int si_type = extract32(info->si_code, 16, 16);
     int si_code = sextract32(info->si_code, 0, 16);
@@ -1178,7 +1181,13 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig,
     /* dequeue signal */
     k->pending = 0;
 
-    sig = gdb_handlesig(cpu, sig);
+    /*
+     * Writes out siginfo values byteswapped, accordingly to the target. It also
+     * cleans the si_type from si_code making it correct for the target.
+     */
+    tswap_siginfo(&k->info, &k->info);
+
+    sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info));
     if (!sig) {
         sa = NULL;
         handler = TARGET_SIG_IGN;

linux-user/sparc/signal.c

@@ -333,7 +333,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     __put_user(0, &sf->rwin_save);  /* TODO: save_rwin_state */
 
-    tswap_siginfo(&sf->info, info);
+    sf->info = *info;
     tswap_sigset(&sf->mask, set);
     target_save_altstack(&sf->stack, env);
 

linux-user/xtensa/signal.c

@@ -184,7 +184,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     if (ka->sa_flags & SA_SIGINFO) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
     }
 
     __put_user(0, &frame->uc.tuc_flags);

tests/tcg/multiarch/Makefile.target

@@ -71,6 +71,13 @@ run-gdbstub-qxfer-auxv-read: sha1
 		--bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \
 	basic gdbstub qXfer:auxv:read support)
 
+run-gdbstub-qxfer-siginfo-read: segfault
+	$(call run-test, $@, $(GDB_SCRIPT) \
+		--gdb $(GDB) \
+		--qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
+		--bin "$< -s" --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-siginfo-read.py, \
+	basic gdbstub qXfer:siginfo:read support)
+
 run-gdbstub-proc-mappings: sha1
 	$(call run-test, $@, $(GDB_SCRIPT) \
 		--gdb $(GDB) \
@@ -128,7 +135,8 @@ EXTRA_RUNS += run-gdbstub-sha1 run-gdbstub-qxfer-auxv-read \
 	      run-gdbstub-proc-mappings run-gdbstub-thread-breakpoint \
 	      run-gdbstub-registers run-gdbstub-prot-none \
 	      run-gdbstub-catch-syscalls run-gdbstub-follow-fork-mode-child \
-	      run-gdbstub-follow-fork-mode-parent
+	      run-gdbstub-follow-fork-mode-parent \
+	      run-gdbstub-qxfer-siginfo-read
 
 # ARM Compatible Semi Hosting Tests
 #

tests/tcg/multiarch/gdbstub/test-qxfer-siginfo-read.py

@@ -0,0 +1,26 @@
+from __future__ import print_function
+#
+# Test gdbstub Xfer:siginfo:read stub.
+#
+# The test runs a binary that causes a SIGSEGV and then looks for additional
+# info about the signal through printing GDB's '$_siginfo' special variable,
+# which sends a Xfer:siginfo:read query to the gdbstub.
+#
+# The binary causes a SIGSEGV at dereferencing a pointer with value 0xdeadbeef,
+# so the test looks for and checks if this address is correctly reported by the
+# gdbstub.
+#
+# This is launched via tests/guest-debug/run-test.py
+#
+
+import gdb
+from test_gdbstub import main, report
+
+def run_test():
+    "Run through the test"
+
+    gdb.execute("continue", False, True)
+    resp = gdb.execute("print/x $_siginfo", False, True)
+    report(resp.find("si_addr = 0xdeadbeef"), "Found fault address.")
+
+main(run_test)

tests/tcg/multiarch/segfault.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <string.h>
+
+/* Cause a segfault for testing purposes. */
+
+int main(int argc, char *argv[])
+{
+    int *ptr = (void *)0xdeadbeef;
+
+    if (argc == 2 && strcmp(argv[1], "-s") == 0) {
+        /* Cause segfault. */
+        printf("%d\n", *ptr);
+    }
+}

tests/vm/basevm.py

@@ -606,7 +606,7 @@ def parse_args(vmcls):
     parser.add_argument("--build-qemu",
                         help="build QEMU from source in guest")
     parser.add_argument("--build-target",
-                        help="QEMU build target", default="check")
+                        help="QEMU build target", default="all check")
     parser.add_argument("--build-path", default=None,
                         help="Path of build directory, "\
                         "for using build tree QEMU binary. ")