[Qemu-devel] [PATCH 15/22] kvm: Add MCE signal support for !CONFIG_IOTHREAD

[Jan Kiszka <jan.kiszka@siemens.com>]

Currently, we only configure and process MCE-related SIGBUS events if
CONFIG_IOTHREAD is enabled. The groundwork is laid, we just need to
factor out the required handler registration and system configuration.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
CC: Huang Ying <ying.huang@intel.com>
CC: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
CC: Jin Dongming <jin.dongming@np.css.fujitsu.com>
---
 cpus.c |  106 ++++++++++++++++++++++++++++++++++++++++------------------------
 1 files changed, 66 insertions(+), 40 deletions(-)

diff --git a/cpus.c b/cpus.c
index 29b1070..bba59e5 100644
--- a/cpus.c
+++ b/cpus.c
@@ -34,9 +34,6 @@
 
 #include "cpus.h"
 #include "compatfd.h"
-#ifdef CONFIG_LINUX
-#include <sys/prctl.h>
-#endif
 
 #ifdef SIGRTMIN
 #define SIG_IPI (SIGRTMIN+4)
@@ -44,10 +41,24 @@
 #define SIG_IPI SIGUSR1
 #endif
 
+#ifdef CONFIG_LINUX
+
+#include <sys/prctl.h>
+
 #ifndef PR_MCE_KILL
 #define PR_MCE_KILL 33
 #endif
 
+#ifndef PR_MCE_KILL_SET
+#define PR_MCE_KILL_SET 1
+#endif
+
+#ifndef PR_MCE_KILL_EARLY
+#define PR_MCE_KILL_EARLY 1
+#endif
+
+#endif /* CONFIG_LINUX */
+
 static CPUState *next_cpu;
 
 /***********************************************************/
@@ -166,6 +177,52 @@ static void cpu_debug_handler(CPUState *env)
     vm_stop(EXCP_DEBUG);
 }
 
+#ifdef CONFIG_LINUX
+static void sigbus_reraise(void)
+{
+    sigset_t set;
+    struct sigaction action;
+
+    memset(&action, 0, sizeof(action));
+    action.sa_handler = SIG_DFL;
+    if (!sigaction(SIGBUS, &action, NULL)) {
+        raise(SIGBUS);
+        sigemptyset(&set);
+        sigaddset(&set, SIGBUS);
+        sigprocmask(SIG_UNBLOCK, &set, NULL);
+    }
+    perror("Failed to re-raise SIGBUS!\n");
+    abort();
+}
+
+static void sigbus_handler(int n, struct qemu_signalfd_siginfo *siginfo,
+                           void *ctx)
+{
+    if (kvm_on_sigbus(siginfo->ssi_code,
+                      (void *)(intptr_t)siginfo->ssi_addr)) {
+        sigbus_reraise();
+    }
+}
+
+static void qemu_init_sigbus(void)
+{
+    struct sigaction action;
+
+    memset(&action, 0, sizeof(action));
+    action.sa_flags = SA_SIGINFO;
+    action.sa_sigaction = (void (*)(int, siginfo_t*, void*))sigbus_handler;
+    sigaction(SIGBUS, &action, NULL);
+
+    prctl(PR_MCE_KILL, PR_MCE_KILL_SET, PR_MCE_KILL_EARLY, 0, 0);
+}
+
+#else /* !CONFIG_LINUX */
+
+static void qemu_init_sigbus(void)
+{
+}
+#endif /* !CONFIG_LINUX */
+
 #ifndef _WIN32
 static int io_thread_fd = -1;
 
@@ -248,6 +305,7 @@ static void qemu_kvm_init_cpu_signals(CPUState *env)
 #ifndef CONFIG_IOTHREAD
     sigemptyset(&set);
     sigaddset(&set, SIG_IPI);
+    sigaddset(&set, SIGBUS);
     pthread_sigmask(SIG_BLOCK, &set, NULL);
 #endif
 
@@ -338,13 +396,11 @@ static void qemu_kvm_eat_signals(CPUState *env)
         }
 
         switch (r) {
-#ifdef CONFIG_IOTHREAD
         case SIGBUS:
             if (kvm_on_sigbus_vcpu(env, siginfo.si_code, siginfo.si_addr)) {
                 sigbus_reraise();
             }
             break;
-#endif
         default:
             break;
         }
@@ -408,6 +464,7 @@ int qemu_init_main_loop(void)
     int ret;
 
     sigemptyset(&blocked_signals);
+    sigaddset(&blocked_signals, SIGBUS);
     if (kvm_enabled()) {
         /*
          * We need to process timer signals synchronously to avoid a race
@@ -424,6 +481,8 @@ int qemu_init_main_loop(void)
 #endif
     cpu_set_debug_excp_handler(cpu_debug_handler);
 
+    qemu_init_sigbus();
+
     return qemu_event_init();
 }
 
@@ -535,13 +594,9 @@ static void qemu_tcg_init_cpu_signals(void)
     pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 }
 
-static void sigbus_handler(int n, struct qemu_signalfd_siginfo *siginfo,
-                           void *ctx);
-
 static sigset_t block_io_signals(void)
 {
     sigset_t set;
-    struct sigaction action;
 
     /* SIGUSR2 used by posix-aio-compat.c */
     sigemptyset(&set);
@@ -555,12 +610,6 @@ static sigset_t block_io_signals(void)
     sigaddset(&set, SIGBUS);
     pthread_sigmask(SIG_BLOCK, &set, NULL);
 
-    memset(&action, 0, sizeof(action));
-    action.sa_flags = SA_SIGINFO;
-    action.sa_sigaction = (void (*)(int, siginfo_t*, void*))sigbus_handler;
-    sigaction(SIGBUS, &action, NULL);
-    prctl(PR_MCE_KILL, 1, 1, 0, 0);
-
     return set;
 }
 
@@ -571,6 +620,8 @@ int qemu_init_main_loop(void)
 
     cpu_set_debug_excp_handler(cpu_debug_handler);
 
+    qemu_init_sigbus();
+
     blocked_signals = block_io_signals();
 
     ret = qemu_signalfd_init(blocked_signals);
@@ -678,31 +729,6 @@ static void qemu_tcg_wait_io_event(void)
     }
 }
 
-static void sigbus_reraise(void)
-{
-    sigset_t set;
-    struct sigaction action;
-
-    memset(&action, 0, sizeof(action));
-    action.sa_handler = SIG_DFL;
-    if (!sigaction(SIGBUS, &action, NULL)) {
-        raise(SIGBUS);
-        sigemptyset(&set);
-        sigaddset(&set, SIGBUS);
-        sigprocmask(SIG_UNBLOCK, &set, NULL);
-    }
-    perror("Failed to re-raise SIGBUS!\n");
-    abort();
-}
-
-static void sigbus_handler(int n, struct qemu_signalfd_siginfo *siginfo,
-                           void *ctx)
-{
-    if (kvm_on_sigbus(siginfo->ssi_code, (void *)(intptr_t)siginfo->ssi_addr)) {
-        sigbus_reraise();
-    }
-}
-
 static void qemu_kvm_wait_io_event(CPUState *env)
 {
     while (!cpu_has_work(env))
-- 
1.7.1