[Qemu-devel] [PATCH] Handle init/sipi in a main cpu exec loop.

[Gleb Natapov]

Currently INIT/SIPI is handled in the context of CPU that sends IPI.
This patch changes this to handle them like all other events in a main
cpu exec loop. When KVM will gain thread per vcpu capability it will
be much more clear to handle those event by cpu thread itself and not
modify one cpu's state from the context of the other.

Signed-off-by: Gleb Natapov <address@hidden>
diff --git a/cpu-all.h b/cpu-all.h
index 48a9a2c..97a224d 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -768,6 +768,8 @@ extern int use_icount;
 #define CPU_INTERRUPT_DEBUG  0x80 /* Debug event occured.  */
 #define CPU_INTERRUPT_VIRQ   0x100 /* virtual interrupt pending.  */
 #define CPU_INTERRUPT_NMI    0x200 /* NMI pending. */
+#define CPU_INTERRUPT_INIT   0x400 /* INIT pending. */
+#define CPU_INTERRUPT_SIPI   0x800 /* SIPI pending. */
 
 void cpu_interrupt(CPUState *s, int mask);
 void cpu_reset_interrupt(CPUState *env, int mask);
diff --git a/cpu-exec.c b/cpu-exec.c
index 8734337..db5cb57 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -380,7 +380,14 @@ int cpu_exec(CPUState *env1)
                     }
 #endif
 #if defined(TARGET_I386)
-                    if (env->hflags2 & HF2_GIF_MASK) {
+                    if (interrupt_request & CPU_INTERRUPT_INIT) {
+                            svm_check_intercept(SVM_EXIT_INIT);
+                            do_cpu_init(env);
+                            env->exception_index = EXCP_HALTED;
+                            cpu_loop_exit();
+                    } else if (interrupt_request & CPU_INTERRUPT_SIPI) {
+                            do_cpu_sipi(env);
+                    } else if (env->hflags2 & HF2_GIF_MASK) {
                         if ((interrupt_request & CPU_INTERRUPT_SMI) &&
                             !(env->hflags & HF_SMM_MASK)) {
                             svm_check_intercept(SVM_EXIT_SMI);
diff --git a/hw/apic.c b/hw/apic.c
index 3e04132..b059185 100644
--- a/hw/apic.c
+++ b/hw/apic.c
@@ -85,6 +85,8 @@ typedef struct APICState {
     int64_t initial_count_load_time, next_time;
     uint32_t idx;
     QEMUTimer *timer;
+    int sipi_vector;
+    int wait_for_sipi;
 } APICState;
 
 static int apic_io_memory;
@@ -93,7 +95,6 @@ static int last_apic_idx = 0;
 static int apic_irq_delivered;
 
 
-static void apic_init_ipi(APICState *s);
 static void apic_set_irq(APICState *s, int vector_num, int trigger_mode);
 static void apic_update_irq(APICState *s);
 static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,
@@ -249,7 +250,7 @@ static void apic_bus_deliver(const uint32_t 
*deliver_bitmask,
         case APIC_DM_INIT:
             /* normal INIT IPI sent to processors */
             foreach_apic(apic_iter, deliver_bitmask,
-                         apic_init_ipi(apic_iter) );
+                         cpu_interrupt(apic_iter->cpu_env, CPU_INTERRUPT_INIT) 
);
             return;
 
         case APIC_DM_EXTINT:
@@ -454,10 +455,14 @@ static void apic_get_delivery_bitmask(uint32_t 
*deliver_bitmask,
 }
 
 
-static void apic_init_ipi(APICState *s)
+void apic_init_reset(CPUState *env)
 {
+    APICState *s = env->apic_state;
     int i;
 
+    if (!s)
+        return;
+
     s->tpr = 0;
     s->spurious_vec = 0xff;
     s->log_dest = 0;
@@ -474,22 +479,31 @@ static void apic_init_ipi(APICState *s)
     s->initial_count = 0;
     s->initial_count_load_time = 0;
     s->next_time = 0;
+    s->wait_for_sipi = 1;
 
-    cpu_reset(s->cpu_env);
-
-    s->cpu_env->halted = !(s->apicbase & MSR_IA32_APICBASE_BSP);
+    env->halted = !(s->apicbase & MSR_IA32_APICBASE_BSP);
 }
 
-/* send a SIPI message to the CPU to start it */
 static void apic_startup(APICState *s, int vector_num)
 {
-    CPUState *env = s->cpu_env;
-    if (!env->halted)
+    s->sipi_vector = vector_num;
+    cpu_interrupt(s->cpu_env, CPU_INTERRUPT_SIPI);
+}
+
+void apic_sipi(CPUState *env)
+{
+    APICState *s = env->apic_state;
+
+    cpu_reset_interrupt(env, CPU_INTERRUPT_SIPI);
+
+    if (!s->wait_for_sipi)
         return;
+
     env->eip = 0;
-    cpu_x86_load_seg_cache(env, R_CS, vector_num << 8, vector_num << 12,
+    cpu_x86_load_seg_cache(env, R_CS, s->sipi_vector << 8, s->sipi_vector << 
12,
                            0xffff, 0);
     env->halted = 0;
+    s->wait_for_sipi = 0;
 }
 
 static void apic_deliver(APICState *s, uint8_t dest, uint8_t dest_mode,
@@ -894,7 +908,8 @@ static void apic_reset(void *opaque)
     s->apicbase = 0xfee00000 |
         (bsp ? MSR_IA32_APICBASE_BSP : 0) | MSR_IA32_APICBASE_ENABLE;
 
-    apic_init_ipi(s);
+    cpu_reset(s->cpu_env);
+    apic_init_reset(s->cpu_env);
 
     if (bsp) {
         /*
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 3cd391a..a50f059 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -888,4 +888,8 @@ static inline void cpu_get_tb_cpu_state(CPUState *env, 
target_ulong *pc,
         (env->eflags & (IOPL_MASK | TF_MASK | RF_MASK | VM_MASK));
 }
 
+void apic_init_reset(CPUState *env);
+void apic_sipi(CPUState *env);
+void do_cpu_init(CPUState *env);
+void do_cpu_sipi(CPUState *env);
 #endif /* CPU_I386_H */
diff --git a/target-i386/exec.h b/target-i386/exec.h
index fbaf5bc..42b471a 100644
--- a/target-i386/exec.h
+++ b/target-i386/exec.h
@@ -345,6 +345,8 @@ static inline int cpu_has_work(CPUState *env)
     work = (env->interrupt_request & CPU_INTERRUPT_HARD) &&
            (env->eflags & IF_MASK);
     work |= env->interrupt_request & CPU_INTERRUPT_NMI;
+    work |= env->interrupt_request & CPU_INTERRUPT_INIT;
+    work |= env->interrupt_request & CPU_INTERRUPT_SIPI;
 
     return work;
 }
diff --git a/target-i386/helper.c b/target-i386/helper.c
index 75e7ccd..03055ec 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -1738,3 +1738,16 @@ CPUX86State *cpu_x86_init(const char *cpu_model)
 
     return env;
 }
+
+void do_cpu_init(CPUState *env)
+{
+    int sipi = env->interrupt_request & CPU_INTERRUPT_SIPI;
+    cpu_reset(env);
+    env->interrupt_request = sipi;
+    apic_init_reset(env);
+}
+
+void do_cpu_sipi(CPUState *env)
+{
+    apic_sipi(env);
+}
--
                        Gleb.