diff mbox series

[v4,07/10] evtchn: add helper for port_is_valid() + evtchn_from_port()

Message ID a2f29b53-c79a-6440-fcaa-97ad28bab0b5@suse.com (mailing list archive)
State Superseded
Headers show
Series evtchn: (not so) recent XSAs follow-on | expand

Commit Message

Jan Beulich Jan. 5, 2021, 1:12 p.m. UTC 
The combination is pretty common, so adding a simple local helper seems
worthwhile. Make it const- and type-correct, in turn requiring the
two called function to also be const-correct (and at this occasion also
make them type-correct).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v4: New.

Comments

Julien Grall Jan. 9, 2021, 4:31 p.m. UTC | #1 
Hi Jan,

On 05/01/2021 13:12, Jan Beulich wrote:
> The combination is pretty common, so adding a simple local helper seems
> worthwhile. Make it const- and type-correct, in turn requiring the
> two called function to also be const-correct (and at this occasion also
> make them type-correct).

Acked-by: Julien Grall <jgrall@amazon.com>

Cheers,

> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> ---
> v4: New.
> 
> --- a/xen/common/event_channel.c
> +++ b/xen/common/event_channel.c
> @@ -147,6 +147,11 @@ static bool virq_is_global(unsigned int
>       return true;
>   }
>   
> +static struct evtchn *_evtchn_from_port(const struct domain *d,
> +                                        evtchn_port_t port)
> +{
> +    return port_is_valid(d, port) ? evtchn_from_port(d, port) : NULL;
> +}
>   
>   static struct evtchn *alloc_evtchn_bucket(struct domain *d, unsigned int port)
>   {
> @@ -361,9 +366,9 @@ static long evtchn_bind_interdomain(evtc
>           ERROR_EXIT(lport);
>       lchn = evtchn_from_port(ld, lport);
>   
> -    if ( !port_is_valid(rd, rport) )
> +    rchn = _evtchn_from_port(rd, rport);
> +    if ( !rchn )
>           ERROR_EXIT_DOM(-EINVAL, rd);
> -    rchn = evtchn_from_port(rd, rport);
>   
>       double_evtchn_lock(lchn, rchn);
>   
> @@ -600,15 +605,12 @@ static long evtchn_bind_pirq(evtchn_bind
>   int evtchn_close(struct domain *d1, int port1, bool guest)
>   {
>       struct domain *d2 = NULL;
> -    struct evtchn *chn1, *chn2;
> -    int            port2;
> +    struct evtchn *chn1 = _evtchn_from_port(d1, port1), *chn2;
>       long           rc = 0;
>   
> -    if ( !port_is_valid(d1, port1) )
> +    if ( !chn1 )
>           return -EINVAL;
>   
> -    chn1 = evtchn_from_port(d1, port1);
> -
>    again:
>       write_lock(&d1->event_lock);
>   
> @@ -695,10 +697,8 @@ int evtchn_close(struct domain *d1, int
>               goto out;
>           }
>   
> -        port2 = chn1->u.interdomain.remote_port;
> -        BUG_ON(!port_is_valid(d2, port2));
> -
> -        chn2 = evtchn_from_port(d2, port2);
> +        chn2 = _evtchn_from_port(d2, chn1->u.interdomain.remote_port);
> +        BUG_ON(!chn2);
>           BUG_ON(chn2->state != ECS_INTERDOMAIN);
>           BUG_ON(chn2->u.interdomain.remote_dom != d1);
>   
> @@ -736,15 +736,13 @@ int evtchn_close(struct domain *d1, int
>   
>   int evtchn_send(struct domain *ld, unsigned int lport)
>   {
> -    struct evtchn *lchn, *rchn;
> +    struct evtchn *lchn = _evtchn_from_port(ld, lport), *rchn;
>       struct domain *rd;
>       int            rport, ret = 0;
>   
> -    if ( !port_is_valid(ld, lport) )
> +    if ( !lchn )
>           return -EINVAL;
>   
> -    lchn = evtchn_from_port(ld, lport);
> -
>       evtchn_read_lock(lchn);
>   
>       /* Guest cannot send via a Xen-attached event channel. */
> @@ -956,7 +954,6 @@ int evtchn_status(evtchn_status_t *statu
>   {
>       struct domain   *d;
>       domid_t          dom = status->dom;
> -    int              port = status->port;
>       struct evtchn   *chn;
>       long             rc = 0;
>   
> @@ -964,14 +961,13 @@ int evtchn_status(evtchn_status_t *statu
>       if ( d == NULL )
>           return -ESRCH;
>   
> -    if ( !port_is_valid(d, port) )
> +    chn = _evtchn_from_port(d, status->port);
> +    if ( !chn )
>       {
>           rcu_unlock_domain(d);
>           return -EINVAL;
>       }
>   
> -    chn = evtchn_from_port(d, port);
> -
>       evtchn_read_lock(chn);
>   
>       if ( consumer_is_xen(chn) )
> @@ -1036,11 +1032,10 @@ long evtchn_bind_vcpu(unsigned int port,
>       if ( (v = domain_vcpu(d, vcpu_id)) == NULL )
>           return -ENOENT;
>   
> -    if ( !port_is_valid(d, port) )
> +    chn = _evtchn_from_port(d, port);
> +    if ( !chn )
>           return -EINVAL;
>   
> -    chn = evtchn_from_port(d, port);
> -
>       write_lock(&d->event_lock);
>   
>       /* Guest cannot re-bind a Xen-attached event channel. */
> @@ -1086,13 +1081,11 @@ long evtchn_bind_vcpu(unsigned int port,
>   int evtchn_unmask(unsigned int port)
>   {
>       struct domain *d = current->domain;
> -    struct evtchn *evtchn;
> +    struct evtchn *evtchn = _evtchn_from_port(d, port);
>   
> -    if ( unlikely(!port_is_valid(d, port)) )
> +    if ( unlikely(!evtchn) )
>           return -EINVAL;
>   
> -    evtchn = evtchn_from_port(d, port);
> -
>       evtchn_read_lock(evtchn);
>   
>       evtchn_port_unmask(d, evtchn);
> @@ -1175,14 +1168,12 @@ static long evtchn_set_priority(const st
>   {
>       struct domain *d = current->domain;
>       unsigned int port = set_priority->port;
> -    struct evtchn *chn;
> +    struct evtchn *chn = _evtchn_from_port(d, port);
>       long ret;
>   
> -    if ( !port_is_valid(d, port) )
> +    if ( !chn )
>           return -EINVAL;
>   
> -    chn = evtchn_from_port(d, port);
> -
>       evtchn_read_lock(chn);
>   
>       ret = evtchn_port_set_priority(d, chn, set_priority->priority);
> @@ -1408,10 +1399,10 @@ void free_xen_event_channel(struct domai
>   
>   void notify_via_xen_event_channel(struct domain *ld, int lport)
>   {
> -    struct evtchn *lchn, *rchn;
> +    struct evtchn *lchn = _evtchn_from_port(ld, lport), *rchn;
>       struct domain *rd;
>   
> -    if ( !port_is_valid(ld, lport) )
> +    if ( !lchn )
>       {
>           /*
>            * Make sure ->is_dying is read /after/ ->valid_evtchns, pairing
> @@ -1422,8 +1413,6 @@ void notify_via_xen_event_channel(struct
>           return;
>       }
>   
> -    lchn = evtchn_from_port(ld, lport);
> -
>       if ( !evtchn_read_trylock(lchn) )
>           return;
>   
> @@ -1577,16 +1566,17 @@ static void domain_dump_evtchn_info(stru
>              "Polling vCPUs: {%*pbl}\n"
>              "    port [p/m/s]\n", d->domain_id, d->max_vcpus, d->poll_mask);
>   
> -    for ( port = 1; port_is_valid(d, port); ++port )
> +    for ( port = 1; ; ++port )
>       {
> -        struct evtchn *chn;
> +        struct evtchn *chn = _evtchn_from_port(d, port);
>           char *ssid;
>   
> +        if ( !chn )
> +            break;
> +
>           if ( !(port & 0x3f) )
>               process_pending_softirqs();
>   
> -        chn = evtchn_from_port(d, port);
> -
>           if ( !evtchn_read_trylock(chn) )
>           {
>               printk("    %4u in flux\n", port);
> --- a/xen/include/xen/event.h
> +++ b/xen/include/xen/event.h
> @@ -120,7 +120,7 @@ static inline void evtchn_read_unlock(st
>       read_unlock(&evtchn->lock);
>   }
>   
> -static inline bool_t port_is_valid(struct domain *d, unsigned int p)
> +static inline bool port_is_valid(const struct domain *d, evtchn_port_t p)
>   {
>       if ( p >= read_atomic(&d->valid_evtchns) )
>           return false;
> @@ -135,7 +135,8 @@ static inline bool_t port_is_valid(struc
>       return true;
>   }
>   
> -static inline struct evtchn *evtchn_from_port(struct domain *d, unsigned int p)
> +static inline struct evtchn *evtchn_from_port(const struct domain *d,
> +                                              evtchn_port_t p)
>   {
>       if ( p < EVTCHNS_PER_BUCKET )
>           return &d->evtchn[array_index_nospec(p, EVTCHNS_PER_BUCKET)];
>
diff mbox series

Patch

--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -147,6 +147,11 @@  static bool virq_is_global(unsigned int
     return true;
 }
 
+static struct evtchn *_evtchn_from_port(const struct domain *d,
+                                        evtchn_port_t port)
+{
+    return port_is_valid(d, port) ? evtchn_from_port(d, port) : NULL;
+}
 
 static struct evtchn *alloc_evtchn_bucket(struct domain *d, unsigned int port)
 {
@@ -361,9 +366,9 @@  static long evtchn_bind_interdomain(evtc
         ERROR_EXIT(lport);
     lchn = evtchn_from_port(ld, lport);
 
-    if ( !port_is_valid(rd, rport) )
+    rchn = _evtchn_from_port(rd, rport);
+    if ( !rchn )
         ERROR_EXIT_DOM(-EINVAL, rd);
-    rchn = evtchn_from_port(rd, rport);
 
     double_evtchn_lock(lchn, rchn);
 
@@ -600,15 +605,12 @@  static long evtchn_bind_pirq(evtchn_bind
 int evtchn_close(struct domain *d1, int port1, bool guest)
 {
     struct domain *d2 = NULL;
-    struct evtchn *chn1, *chn2;
-    int            port2;
+    struct evtchn *chn1 = _evtchn_from_port(d1, port1), *chn2;
     long           rc = 0;
 
-    if ( !port_is_valid(d1, port1) )
+    if ( !chn1 )
         return -EINVAL;
 
-    chn1 = evtchn_from_port(d1, port1);
-
  again:
     write_lock(&d1->event_lock);
 
@@ -695,10 +697,8 @@  int evtchn_close(struct domain *d1, int
             goto out;
         }
 
-        port2 = chn1->u.interdomain.remote_port;
-        BUG_ON(!port_is_valid(d2, port2));
-
-        chn2 = evtchn_from_port(d2, port2);
+        chn2 = _evtchn_from_port(d2, chn1->u.interdomain.remote_port);
+        BUG_ON(!chn2);
         BUG_ON(chn2->state != ECS_INTERDOMAIN);
         BUG_ON(chn2->u.interdomain.remote_dom != d1);
 
@@ -736,15 +736,13 @@  int evtchn_close(struct domain *d1, int
 
 int evtchn_send(struct domain *ld, unsigned int lport)
 {
-    struct evtchn *lchn, *rchn;
+    struct evtchn *lchn = _evtchn_from_port(ld, lport), *rchn;
     struct domain *rd;
     int            rport, ret = 0;
 
-    if ( !port_is_valid(ld, lport) )
+    if ( !lchn )
         return -EINVAL;
 
-    lchn = evtchn_from_port(ld, lport);
-
     evtchn_read_lock(lchn);
 
     /* Guest cannot send via a Xen-attached event channel. */
@@ -956,7 +954,6 @@  int evtchn_status(evtchn_status_t *statu
 {
     struct domain   *d;
     domid_t          dom = status->dom;
-    int              port = status->port;
     struct evtchn   *chn;
     long             rc = 0;
 
@@ -964,14 +961,13 @@  int evtchn_status(evtchn_status_t *statu
     if ( d == NULL )
         return -ESRCH;
 
-    if ( !port_is_valid(d, port) )
+    chn = _evtchn_from_port(d, status->port);
+    if ( !chn )
     {
         rcu_unlock_domain(d);
         return -EINVAL;
     }
 
-    chn = evtchn_from_port(d, port);
-
     evtchn_read_lock(chn);
 
     if ( consumer_is_xen(chn) )
@@ -1036,11 +1032,10 @@  long evtchn_bind_vcpu(unsigned int port,
     if ( (v = domain_vcpu(d, vcpu_id)) == NULL )
         return -ENOENT;
 
-    if ( !port_is_valid(d, port) )
+    chn = _evtchn_from_port(d, port);
+    if ( !chn )
         return -EINVAL;
 
-    chn = evtchn_from_port(d, port);
-
     write_lock(&d->event_lock);
 
     /* Guest cannot re-bind a Xen-attached event channel. */
@@ -1086,13 +1081,11 @@  long evtchn_bind_vcpu(unsigned int port,
 int evtchn_unmask(unsigned int port)
 {
     struct domain *d = current->domain;
-    struct evtchn *evtchn;
+    struct evtchn *evtchn = _evtchn_from_port(d, port);
 
-    if ( unlikely(!port_is_valid(d, port)) )
+    if ( unlikely(!evtchn) )
         return -EINVAL;
 
-    evtchn = evtchn_from_port(d, port);
-
     evtchn_read_lock(evtchn);
 
     evtchn_port_unmask(d, evtchn);
@@ -1175,14 +1168,12 @@  static long evtchn_set_priority(const st
 {
     struct domain *d = current->domain;
     unsigned int port = set_priority->port;
-    struct evtchn *chn;
+    struct evtchn *chn = _evtchn_from_port(d, port);
     long ret;
 
-    if ( !port_is_valid(d, port) )
+    if ( !chn )
         return -EINVAL;
 
-    chn = evtchn_from_port(d, port);
-
     evtchn_read_lock(chn);
 
     ret = evtchn_port_set_priority(d, chn, set_priority->priority);
@@ -1408,10 +1399,10 @@  void free_xen_event_channel(struct domai
 
 void notify_via_xen_event_channel(struct domain *ld, int lport)
 {
-    struct evtchn *lchn, *rchn;
+    struct evtchn *lchn = _evtchn_from_port(ld, lport), *rchn;
     struct domain *rd;
 
-    if ( !port_is_valid(ld, lport) )
+    if ( !lchn )
     {
         /*
          * Make sure ->is_dying is read /after/ ->valid_evtchns, pairing
@@ -1422,8 +1413,6 @@  void notify_via_xen_event_channel(struct
         return;
     }
 
-    lchn = evtchn_from_port(ld, lport);
-
     if ( !evtchn_read_trylock(lchn) )
         return;
 
@@ -1577,16 +1566,17 @@  static void domain_dump_evtchn_info(stru
            "Polling vCPUs: {%*pbl}\n"
            "    port [p/m/s]\n", d->domain_id, d->max_vcpus, d->poll_mask);
 
-    for ( port = 1; port_is_valid(d, port); ++port )
+    for ( port = 1; ; ++port )
     {
-        struct evtchn *chn;
+        struct evtchn *chn = _evtchn_from_port(d, port);
         char *ssid;
 
+        if ( !chn )
+            break;
+
         if ( !(port & 0x3f) )
             process_pending_softirqs();
 
-        chn = evtchn_from_port(d, port);
-
         if ( !evtchn_read_trylock(chn) )
         {
             printk("    %4u in flux\n", port);
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -120,7 +120,7 @@  static inline void evtchn_read_unlock(st
     read_unlock(&evtchn->lock);
 }
 
-static inline bool_t port_is_valid(struct domain *d, unsigned int p)
+static inline bool port_is_valid(const struct domain *d, evtchn_port_t p)
 {
     if ( p >= read_atomic(&d->valid_evtchns) )
         return false;
@@ -135,7 +135,8 @@  static inline bool_t port_is_valid(struc
     return true;
 }
 
-static inline struct evtchn *evtchn_from_port(struct domain *d, unsigned int p)
+static inline struct evtchn *evtchn_from_port(const struct domain *d,
+                                              evtchn_port_t p)
 {
     if ( p < EVTCHNS_PER_BUCKET )
         return &d->evtchn[array_index_nospec(p, EVTCHNS_PER_BUCKET)];