[PATCH v2] xen/events: fix global virq handling

[Jan Beulich <jbeulich@xxxxxxxx>]

VIRQs are split into "global" and "per vcpu" ones. Unfortunately in
reality there are "per domain" ones, too.

send_global_virq() and set_global_virq_handler() make only sense for
the real "global" ones, so replace virq_is_global() with a new
function get_virq_type() returning one of the 3 possible types (global,
domain, vcpu VIRQ).

To make its intended purpose more clear, also rename
send_guest_global_virq() to send_guest_domain_virq().

Fixes: 980822c5edd1 ("xen/events: allow setting of global virq handler only for 
unbound virqs")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
As I don't have much time today (I'm having a day off), only compile
tested. Please try a CI run with this patch before applying!

Whether the "domain" infix in send_guest_domain_virq() is really useful
I don't know. Maybe we should go even father with renaming, to have
{vcpu,domain}_send_virq()?
---
v2: Also rename send_guest_global_virq().

--- a/xen/arch/arm/include/asm/event.h
+++ b/xen/arch/arm/include/asm/event.h
@@ -47,9 +47,9 @@ static inline void local_event_delivery_
 }
 
 /* No arch specific virq definition now. Default to global. */
-static inline bool arch_virq_is_global(unsigned int virq)
+static inline enum virq_type arch_get_virq_type(unsigned int virq)
 {
-    return true;
+    return VIRQ_GLOBAL;
 }
 
 #endif
--- a/xen/arch/ppc/include/asm/event.h
+++ b/xen/arch/ppc/include/asm/event.h
@@ -17,9 +17,9 @@ static inline int vcpu_event_delivery_is
 }
 
 /* No arch specific virq definition now. Default to global. */
-static inline bool arch_virq_is_global(unsigned int virq)
+static inline enum virq_type arch_get_virq_type(unsigned int virq)
 {
-    return true;
+    return VIRQ_GLOBAL;
 }
 
 static inline int local_events_need_delivery(void)
--- a/xen/arch/riscv/include/asm/event.h
+++ b/xen/arch/riscv/include/asm/event.h
@@ -24,9 +24,9 @@ static inline void local_event_delivery_
 }
 
 /* No arch specific virq definition now. Default to global. */
-static inline bool arch_virq_is_global(unsigned int virq)
+static inline enum virq_type arch_get_virq_type(unsigned int virq)
 {
-    return true;
+    return VIRQ_GLOBAL;
 }
 
 #endif /* ASM__RISCV__EVENT_H */
--- a/xen/arch/x86/include/asm/event.h
+++ b/xen/arch/x86/include/asm/event.h
@@ -41,10 +41,10 @@ static inline void local_event_delivery_
     vcpu_info(current, evtchn_upcall_mask) = 0;
 }
 
-/* No arch specific virq definition now. Default to global. */
-static inline bool arch_virq_is_global(unsigned int virq)
+/* Only global arch specific virq definitions. */
+static inline enum virq_type arch_get_virq_type(unsigned int virq)
 {
-    return true;
+    return VIRQ_GLOBAL;
 }
 
 #ifdef CONFIG_PV_SHIM
--- a/xen/common/argo.c
+++ b/xen/common/argo.c
@@ -440,7 +440,7 @@ signal_domain(struct domain *d)
 {
     argo_dprintk("signalling domid:%u\n", d->domain_id);
 
-    send_guest_global_virq(d, VIRQ_ARGO);
+    send_guest_domain_virq(d, VIRQ_ARGO);
 }
 
 static void
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -127,7 +127,7 @@ static struct domain *get_global_virq_ha
     return global_virq_handlers[virq] ?: hardware_domain;
 }
 
-static bool virq_is_global(unsigned int virq)
+static enum virq_type get_virq_type(unsigned int virq)
 {
     switch ( virq )
     {
@@ -135,14 +135,17 @@ static bool virq_is_global(unsigned int
     case VIRQ_DEBUG:
     case VIRQ_XENOPROF:
     case VIRQ_XENPMU:
-        return false;
+        return VIRQ_VCPU;
+
+    case VIRQ_ARGO:
+        return VIRQ_DOMAIN;
 
     case VIRQ_ARCH_0 ... VIRQ_ARCH_7:
-        return arch_virq_is_global(virq);
+        return arch_get_virq_type(virq);
     }
 
     ASSERT(virq < NR_VIRQS);
-    return true;
+    return VIRQ_GLOBAL;
 }
 
 static struct evtchn *_evtchn_from_port(const struct domain *d,
@@ -476,7 +479,7 @@ int evtchn_bind_virq(evtchn_bind_virq_t
     struct domain *d = current->domain;
     int            virq = bind->virq, vcpu = bind->vcpu;
     int            rc = 0;
-    bool           is_global;
+    enum virq_type type;
 
     if ( (virq < 0) || (virq >= ARRAY_SIZE(v->virq_to_evtchn)) )
         return -EINVAL;
@@ -486,9 +489,9 @@ int evtchn_bind_virq(evtchn_bind_virq_t
     * speculative execution.
     */
     virq = array_index_nospec(virq, ARRAY_SIZE(v->virq_to_evtchn));
-    is_global = virq_is_global(virq);
+    type = get_virq_type(virq);
 
-    if ( is_global && vcpu != 0 )
+    if ( type != VIRQ_VCPU && vcpu != 0 )
         return -EINVAL;
 
     if ( (v = domain_vcpu(d, vcpu)) == NULL )
@@ -496,7 +499,7 @@ int evtchn_bind_virq(evtchn_bind_virq_t
 
     write_lock(&d->event_lock);
 
-    if ( is_global && get_global_virq_handler(virq) != d )
+    if ( type == VIRQ_GLOBAL && get_global_virq_handler(virq) != d )
     {
         rc = -EBUSY;
         goto out;
@@ -756,7 +759,8 @@ int evtchn_close(struct domain *d1, int
         if ( chn1->u.virq == VIRQ_DOM_EXC )
             domain_deinit_states(d1);
 
-        v = d1->vcpu[virq_is_global(chn1->u.virq) ? 0 : chn1->notify_vcpu_id];
+        v = d1->vcpu[get_virq_type(chn1->u.virq) != VIRQ_VCPU
+            ? 0 : chn1->notify_vcpu_id];
 
         write_lock_irqsave(&v->virq_lock, flags);
         ASSERT(read_atomic(&v->virq_to_evtchn[chn1->u.virq]) == port1);
@@ -900,7 +904,7 @@ bool evtchn_virq_enabled(const struct vc
     if ( !v )
         return false;
 
-    if ( virq_is_global(virq) && v->vcpu_id )
+    if ( get_virq_type(virq) != VIRQ_VCPU && v->vcpu_id )
         v = domain_vcpu(v->domain, 0);
 
     return read_atomic(&v->virq_to_evtchn[virq]);
@@ -913,7 +917,7 @@ void send_guest_vcpu_virq(struct vcpu *v
     struct domain *d;
     struct evtchn *chn;
 
-    ASSERT(!virq_is_global(virq));
+    ASSERT(get_virq_type(virq) == VIRQ_VCPU);
 
     read_lock_irqsave(&v->virq_lock, flags);
 
@@ -933,14 +937,14 @@ void send_guest_vcpu_virq(struct vcpu *v
     read_unlock_irqrestore(&v->virq_lock, flags);
 }
 
-void send_guest_global_virq(struct domain *d, uint32_t virq)
+void send_guest_domain_virq(struct domain *d, uint32_t virq)
 {
     unsigned long flags;
     int port;
     struct vcpu *v;
     struct evtchn *chn;
 
-    ASSERT(virq_is_global(virq));
+    ASSERT(get_virq_type(virq) != VIRQ_VCPU);
 
     if ( unlikely(d == NULL) || unlikely(d->vcpu == NULL) )
         return;
@@ -995,9 +999,9 @@ static DEFINE_SPINLOCK(global_virq_handl
 
 void send_global_virq(uint32_t virq)
 {
-    ASSERT(virq_is_global(virq));
+    ASSERT(get_virq_type(virq) == VIRQ_GLOBAL);
 
-    send_guest_global_virq(get_global_virq_handler(virq), virq);
+    send_guest_domain_virq(get_global_virq_handler(virq), virq);
 }
 
 int set_global_virq_handler(struct domain *d, uint32_t virq)
@@ -1008,7 +1012,7 @@ int set_global_virq_handler(struct domai
 
     if (virq >= NR_VIRQS)
         return -EINVAL;
-    if (!virq_is_global(virq))
+    if (get_virq_type(virq) != VIRQ_GLOBAL)
         return -EINVAL;
 
     if (global_virq_handlers[virq] == d)
@@ -1204,7 +1208,7 @@ int evtchn_bind_vcpu(evtchn_port_t port,
     switch ( chn->state )
     {
     case ECS_VIRQ:
-        if ( virq_is_global(chn->u.virq) )
+        if ( get_virq_type(chn->u.virq) != VIRQ_VCPU )
             chn->notify_vcpu_id = v->vcpu_id;
         else
             rc = -EINVAL;
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -24,17 +24,17 @@
 void send_guest_vcpu_virq(struct vcpu *v, uint32_t virq);
 
 /*
- * send_global_virq: Notify the domain handling a global VIRQ.
- *  @virq:     Virtual IRQ number (VIRQ_*)
+ * send_guest_domain_virq:
+ *  @d:        Domain to which VIRQ should be sent
+ *  @virq:     Virtual IRQ number (VIRQ_*), may not be per-vCPU
  */
-void send_global_virq(uint32_t virq);
+void send_guest_domain_virq(struct domain *d, uint32_t virq);
 
 /*
- * send_guest_global_virq:
- *  @d:        Domain to which VIRQ should be sent
- *  @virq:     Virtual IRQ number (VIRQ_*), must be global
+ * send_global_virq: Notify the domain handling a global VIRQ.
+ *  @virq:     Virtual IRQ number (VIRQ_*)
  */
-void send_guest_global_virq(struct domain *d, uint32_t virq);
+void send_global_virq(uint32_t virq);
 
 /*
  * sent_global_virq_handler: Set a global VIRQ handler.
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -84,6 +84,12 @@ extern domid_t hardware_domid;
 #define XEN_CONSUMER_BITS 3
 #define NR_XEN_CONSUMERS ((1 << XEN_CONSUMER_BITS) - 1)
 
+enum virq_type {
+    VIRQ_GLOBAL,
+    VIRQ_DOMAIN,
+    VIRQ_VCPU
+};
+
 struct evtchn
 {
     rwlock_t lock;