[PATCH v4 11/15] pvh: Send an SCI on VCPU hotplug event

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

When GPE0 status register gets a bit set (currently XEN_GPE0_CPUHP_BIT
only) send an SCI to the guest.

Also update send_guest_global_virq() to handle cases when VCPU0
is offlined.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
Changes in v4:
* Generate SCI only when needed (i.e. when status changes)
* Deal with VCPU0 being offline

 xen/arch/x86/hvm/acpi.c    | 10 ++++++++++
 xen/common/event_channel.c |  7 +++++--
 xen/include/xen/domain.h   |  1 +
 xen/include/xen/event.h    |  8 ++++++++
 4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/acpi.c b/xen/arch/x86/hvm/acpi.c
index 1c205eb..9b11a52 100644
--- a/xen/arch/x86/hvm/acpi.c
+++ b/xen/arch/x86/hvm/acpi.c
@@ -4,6 +4,7 @@
  */
 #include <xen/acpi.h>
 #include <xen/errno.h>
+#include <xen/event.h>
 #include <xen/lib.h>
 #include <xen/sched.h>
 
@@ -99,6 +100,7 @@ static int acpi_access_common(struct domain *d, bool is_guest_access,
         else if ( mask_sts )
         {
             uint32_t v = *val;
+            uint16_t sts_orig = *sts;
 
             /* Status register is write-1-to-clear by guests */
             switch ( port & 3 )
@@ -132,6 +134,14 @@ static int acpi_access_common(struct domain *d, bool is_guest_access,
             case 3:
                 *en = (((v & 0xff) << 8) | (*en & 0xff)) & *mask_en;
             }
+
+            /*
+             * If a new bit has been set in status register and corresponding
+             * event is enabled then an SCI is sent to the guest.
+             */
+            if ( !is_guest_access &&
+                 ((*sts ^ sts_orig) & ~sts_orig) && (*sts & *en))
+                send_guest_global_virq(d, VIRQ_SCI);
         }
     }
 
diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 638dc5e..1d77373 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -727,7 +727,7 @@ void send_guest_vcpu_virq(struct vcpu *v, uint32_t virq)
     spin_unlock_irqrestore(&v->virq_lock, flags);
 }
 
-static void send_guest_global_virq(struct domain *d, uint32_t virq)
+void send_guest_global_virq(struct domain *d, uint32_t virq)
 {
     unsigned long flags;
     int port;
@@ -739,7 +739,10 @@ static void send_guest_global_virq(struct domain *d, uint32_t virq)
     if ( unlikely(d == NULL) || unlikely(d->vcpu == NULL) )
         return;
 
-    v = d->vcpu[0];
+    /* Send to first available VCPU */
+    for_each_vcpu(d, v)
+        if ( is_vcpu_online(v) )
+            break;
     if ( unlikely(v == NULL) )
         return;
 
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index bce0ea1..b386038 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -52,6 +52,7 @@ void vcpu_destroy(struct vcpu *v);
 int map_vcpu_info(struct vcpu *v, unsigned long gfn, unsigned offset);
 void unmap_vcpu_info(struct vcpu *v);
 
+int arch_update_avail_vcpus(struct domain *d);
 int arch_domain_create(struct domain *d, unsigned int domcr_flags,
                        struct xen_arch_domainconfig *config);
 
diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index 5008c80..74bd605 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -23,6 +23,14 @@
 void send_guest_vcpu_virq(struct vcpu *v, uint32_t virq);
 
 /*
+ * send_guest_global_virq: Notify guest via a global VIRQ.
+ *  @d:        domain to which virtual IRQ should be sent. First
+ *             online VCPU will be selected.
+ *  @virq:     Virtual IRQ number (VIRQ_*)
+ */
+void send_guest_global_virq(struct domain *d, uint32_t virq);
+
+/*
  * send_global_virq: Notify the domain handling a global VIRQ.
  *  @virq:     Virtual IRQ number (VIRQ_*)
  */
-- 
2.7.4


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