x86: Rework local IRQ delivery for APICs
PATCH 3/3 x86: Rework local IRQ delivery for APICs
[ Refreshed and resent version of
http://permalink.gmane.org/gmane.comp.emulators.qemu/23456 ]
This patch reworks the delivery of IRQs directed to a local APIC, handling all requests in a central function, apic_local_deliver(), analogue to apic_bus_deliver().
Futhermore, the APIC_LVT_LINT0 mask initialization is fixed for SMP. Finally, virtual routing of the legacy PIT to the APICs is adopted in so far that pic_irq_request() delivers interrupts through the LINT0 lines of all APICs in the system. This routing allows for emulating the IO-APIC NMI watchdog mechanism, including on SMP, which Linux exploits via its nmi_watchdog=1.
---
hw/apic.c | 63 ++++++++++++++++++++++++++++++++++++++++++-------------------- hw/pc.c | 15 ++++++++++---- hw/pc.h | 3 ++ 3 files changed, 57 insertions(+), 24 deletions(-)
hw/apic.c +0 -0
@@ -166,6 +166,37 @@ static inline void reset_bit(uint32_t *t tab[i] &= ~mask;
}
+void apic_local_deliver(CPUState *env, int vector) +{
+ APICState *s = env->apic_state; + uint32_t lvt = s->lvt[vector]; + int trigger_mode;
+
+ if (lvt & APIC_LVT_MASKED)
+ return;
+
+ switch ((lvt >> 8) & 7) {
+ case APIC_DM_SMI:
+ cpu_interrupt(env, CPU_INTERRUPT_SMI);
+ break;
+
+ case APIC_DM_NMI:
+ cpu_interrupt(env, CPU_INTERRUPT_NMI);
+ break;
+
+ case APIC_DM_EXTINT:
+ cpu_interrupt(env, CPU_INTERRUPT_HARD);
+ break;
+
+ case APIC_DM_FIXED:
+ trigger_mode = APIC_TRIGGER_EDGE;
+ if ((vector == APIC_LVT_LINT0 || vector == APIC_LVT_LINT1) &&
+ (lvt & APIC_LVT_LEVEL_TRIGGER))
+ trigger_mode = APIC_TRIGGER_LEVEL;
+ apic_set_irq(s, lvt & 0xff, trigger_mode);
+ }
+}
+
#define foreach_apic(apic, deliver_bitmask, code) \
{\
int __i, __j, __mask;\@@ -502,10 +533,8 @@ int apic_accept_pic_intr(CPUState *env)
lvt0 = s->lvt[APIC_LVT_LINT0];
- if (s->id == 0 &&
- ((s->apicbase & MSR_IA32_APICBASE_ENABLE) == 0 ||
- ((lvt0 & APIC_LVT_MASKED) == 0 &&
- ((lvt0 >> 8) & 0x7) == APIC_DM_EXTINT)))
+ if ((s->apicbase & MSR_IA32_APICBASE_ENABLE) == 0 ||
+ (lvt0 & APIC_LVT_MASKED) == 0)
return 1;
return 0;
@@ -556,9 +585,7 @@ static void apic_timer(void *opaque)
{
APICState *s = opaque;- if (!(s->lvt[APIC_LVT_TIMER] & APIC_LVT_MASKED)) {
- apic_set_irq(s, s->lvt[APIC_LVT_TIMER] & 0xff, APIC_TRIGGER_EDGE);
- }
+ apic_local_deliver(s->cpu_env, APIC_LVT_TIMER);
apic_timer_update(s, s->next_time);
}@@ -821,12 +848,14 @@ static void apic_reset(void *opaque)
APICState *s = opaque;
apic_init_ipi(s);- /*
- * LINT0 delivery mode is set to ExtInt at initialization time
- * typically by BIOS, so PIC interrupt can be delivered to the
- * processor when local APIC is enabled.
- */
- s->lvt[APIC_LVT_LINT0] = 0x700;
+ if (s->id == 0) {
+ /*
+ * LINT0 delivery mode on CPU #0 is set to ExtInt at initialization
+ * time typically by BIOS, so PIC interrupt can be delivered to the
+ * processor when local APIC is enabled.
+ */+ s->lvt[APIC_LVT_LINT0] = 0x700;
+ }
}
static CPUReadMemoryFunc *apic_mem_read[3] = { @@ -851,19 +880,13 @@ int apic_init(CPUState *env)
if (!s)
return -1;
env->apic_state = s;
- apic_init_ipi(s);
s->id = last_apic_id++;
env->cpuid_apic_id = s->id;
s->cpu_env = env;
s->apicbase = 0xfee00000 |
(s->id ? 0 : MSR_IA32_APICBASE_BSP) | MSR_IA32_APICBASE_ENABLE;- /*
- * LINT0 delivery mode is set to ExtInt at initialization time - * typically by BIOS, so PIC interrupt can be delivered to the - * processor when local APIC is enabled. - */
- s->lvt[APIC_LVT_LINT0] = 0x700;
+ apic_reset(s);
/* XXX: mapping more APICs at the same memory location */
if (apic_io_memory == 0) {hw/pc.c +0 -0
@@ -113,9 +113,16 @@ int cpu_get_pic_interrupt(CPUState *env)
static void pic_irq_request(void *opaque, int irq, int level) {
- CPUState *env = opaque;
- if (level && apic_accept_pic_intr(env))
- cpu_interrupt(env, CPU_INTERRUPT_HARD);
+ CPUState *env = first_cpu;
+
+ if (!level)
+ return;
+
+ while (env) {
+ if (apic_accept_pic_intr(env))
+ apic_local_deliver(env, APIC_LINT0);
+ env = env->next_cpu;
+ }
}
/* PC cmos mappings */
@@ -845,7 +852,7 @@ static void pc_init1(int ram_size, int v
if (linux_boot) load_linux(kernel_filename, initrd_filename, kernel_cmdline);
- cpu_irq = qemu_allocate_irqs(pic_irq_request, first_cpu, 1);
+ cpu_irq = qemu_allocate_irqs(pic_irq_request, NULL, 1);
i8259 = i8259_init(cpu_irq[0]);
ferr_irq = i8259[13];hw/pc.h +0 -0
@@ -39,8 +39,11 @@ void irq_info(void);
/* APIC */
typedef struct IOAPICState IOAPICState;
+#define APIC_LINT0 3
+
int apic_init(CPUState *env);
int apic_accept_pic_intr(CPUState *env);
+void apic_local_deliver(CPUState *env, int vector); int apic_get_interrupt(CPUState *env); IOAPICState *ioapic_init(void);
void ioapic_set_irq(void *opaque, int vector, int level);
Quoted 7 lines · Jan Kiszka
[ Refreshed and resent version of
http://permalink.gmane.org/gmane.comp.emulators.qemu/23456 ]This patch reworks the delivery of IRQs directed to a local APIC, handling all requests in a central function,
apic_local_deliver(), analogue toapic_bus_deliver().
Quoted 9 lines
Futhermore, the
APIC_LVT_LINT0mask initialization is fixed for SMP. Finally, virtual routing of the legacy PIT to the APICs is adopted in so far thatpic_irq_request()delivers interrupts through the LINT0 lines of all APICs in the system. This routing allows for emulating the IO-APIC NMI watchdog mechanism, including on SMP, which Linux exploits via its nmi_watchdog=1.Signed-off-by Jan Kiszka <[email protected]>
Non-broken patch attached. Sorry.
Jan
--- hw/apic.c | 63 ++++++++++++++++++++++++++++++++++++++++++-------------------- hw/pc.c | 15 ++++++++++---- hw/pc.h | 3 ++ 3 files changed, 57 insertions(+), 24 deletions(-)
hw/apic.c +43 -20
@@ -166,6 +166,37 @@ static inline void reset_bit(uint32_t *t tab[i] &= ~mask; } +void apic_local_deliver (CPUState *env,int vector) +{ +APICState *s = env->apic_state; +uint32_t lvt = s->lvt[vector]; +int trigger_mode; + +if (lvt &APIC_LVT_MASKED ) +return ; + +switch ((lvt >>8 ) &7 ) { +case APIC_DM_SMI : +cpu_interrupt (env,CPU_INTERRUPT_SMI ); +break ; + +case APIC_DM_NMI : +cpu_interrupt (env,CPU_INTERRUPT_NMI ); +break ; + +case APIC_DM_EXTINT : +cpu_interrupt (env,CPU_INTERRUPT_HARD ); +break ; + +case APIC_DM_FIXED : + trigger_mode =APIC_TRIGGER_EDGE ; +if ((vector ==APIC_LVT_LINT0 || vector ==APIC_LVT_LINT1 ) && + (lvt &APIC_LVT_LEVEL_TRIGGER )) + trigger_mode =APIC_TRIGGER_LEVEL ; +apic_set_irq (s, lvt &0xff , trigger_mode); + } +} +#define foreach_apic (apic, deliver_bitmask, code) \ {\ int __i, __j, __mask;\
@@ -502,10 +533,8 @@ int apic_accept_pic_intr(CPUState *env) lvt0 = s->lvt[APIC_LVT_LINT0 ]; -if (s->id ==0 && - ((s->apicbase &MSR_IA32_APICBASE_ENABLE ) ==0 || - ((lvt0 &APIC_LVT_MASKED ) ==0 && - ((lvt0 >>8 ) &0x7 ) ==APIC_DM_EXTINT ))) +if ((s->apicbase &MSR_IA32_APICBASE_ENABLE ) ==0 || + (lvt0 &APIC_LVT_MASKED ) ==0 )return 1 ;return 0 ;
@@ -556,9 +585,7 @@ static void apic_timer(void *opaque) {APICState *s = opaque; -if (!(s->lvt[APIC_LVT_TIMER ] &APIC_LVT_MASKED )) { -apic_set_irq (s, s->lvt[APIC_LVT_TIMER ] &0xff ,APIC_TRIGGER_EDGE ); - } +apic_local_deliver (s->cpu_env,APIC_LVT_TIMER );apic_timer_update (s, s->next_time); }
@@ -821,12 +848,14 @@ static void apic_reset(void *opaque)APICState *s = opaque;apic_init_ipi (s); -/* -* LINT0 delivery mode is set to ExtInt at initialization time -* typically by BIOS, so PIC interrupt can be delivered to the -* processor when local APIC is enabled. -*/ - s->lvt[APIC_LVT_LINT0 ] =0x700 ; +if (s->id ==0 ) { +/* +* LINT0 delivery mode on CPU #0 is set to ExtInt at initialization +* time typically by BIOS, so PIC interrupt can be delivered to the +* processor when local APIC is enabled. +*/ + s->lvt[APIC_LVT_LINT0 ] =0x700 ; + } }static CPUReadMemoryFunc *apic_mem_read[3 ] = {
@@ -851,19 +880,13 @@ int apic_init(CPUState *env)if (!s)return -1 ; env->apic_state = s; -apic_init_ipi (s); s->id = last_apic_id++; env->cpuid_apic_id = s->id; s->cpu_env = env; s->apicbase =0xfee00000 | (s->id ?0 :MSR_IA32_APICBASE_BSP ) |MSR_IA32_APICBASE_ENABLE ; -/* -* LINT0 delivery mode is set to ExtInt at initialization time -* typically by BIOS, so PIC interrupt can be delivered to the -* processor when local APIC is enabled. -*/ - s->lvt[APIC_LVT_LINT0 ] =0x700 ; +apic_reset (s);/* XXX: mapping more APICs at the same memory location */ if (apic_io_memory ==0 ) {
hw/pc.c +11 -4
@@ -113,9 +113,16 @@ int cpu_get_pic_interrupt(CPUState *env)static void pic_irq_request (void *opaque,int irq,int level) { -CPUState *env = opaque; -if (level &&apic_accept_pic_intr (env)) -cpu_interrupt (env,CPU_INTERRUPT_HARD ); +CPUState *env = first_cpu; + +if (!level) +return ; + +while (env) { +if (apic_accept_pic_intr (env)) +apic_local_deliver (env,APIC_LINT0 ); + env = env->next_cpu; + } }/* PC cmos mappings */
@@ -845,7 +852,7 @@ static void pc_init1(int ram_size, int vif (linux_boot)load_linux (kernel_filename, initrd_filename, kernel_cmdline); - cpu_irq =qemu_allocate_irqs (pic_irq_request, first_cpu,1 ); + cpu_irq =qemu_allocate_irqs (pic_irq_request,NULL ,1 ); i8259 =i8259_init (cpu_irq[0 ]); ferr_irq = i8259[13 ];
hw/pc.h +3 -0
@@ -39,8 +39,11 @@ void irq_info(void);/* APIC */ typedef struct IOAPICState IOAPICState ; +#define APIC_LINT0 3 +int apic_init (CPUState *env);int apic_accept_pic_intr (CPUState *env); +void apic_local_deliver (CPUState *env,int vector);int apic_get_interrupt (CPUState *env);IOAPICState *ioapic_init (void );void ioapic_set_irq (void *opaque,int vector,int level);