[PATCH v6 07/12] pvh: Send an SCI on VCPU hotplug event

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

Send and SCI when VCPU map is updated by domctl or when guest sets
GPE0 enable bit and status bit is already set.

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

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
Changes in v6:
* Change conditions causing the SCI to be generated:
  - domctl write to VCPU map
  - Enabling a pending GPE0 event


 xen/arch/x86/hvm/acpi.c    | 20 ++++++++++++++++++++
 xen/common/event_channel.c |  7 +++++--
 xen/include/xen/domain.h   |  1 +
 xen/include/xen/event.h    |  8 ++++++++
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/acpi.c b/xen/arch/x86/hvm/acpi.c
index 9f0578e..946640e 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>
 
@@ -85,6 +86,17 @@ int hvm_acpi_domctl_access(struct domain *d,
             return -EFAULT;
     }
 
+    /*
+     * For simplicity don't verify whether CPU map changed and
+     * always send an SCI on a write (provided it's enabled).
+     */
+    if ( is_write )
+    {
+        d->arch.hvm_domain.acpi.gpe0_sts |= 1U << XEN_ACPI_GPE0_CPUHP_BIT;
+        if ( d->arch.hvm_domain.acpi.gpe0_en & (1U << XEN_ACPI_GPE0_CPUHP_BIT) )
+            send_guest_global_virq(d, VIRQ_SCI);
+    }
+
     return 0;
 }
 
@@ -144,6 +156,7 @@ static int acpi_guest_access(int dir, unsigned int port,
     else
     {
         uint32_t v = *val;
+        uint16_t en_orig = *en;
 
         /* Status register is write-1-to-clear */
         switch ( port & 3 )
@@ -170,6 +183,13 @@ static int acpi_guest_access(int dir, unsigned int port,
             *en = (((v & 0xff) << 8) | (*en & 0xff)) & *mask_en;
             break;
         }
+
+        /*
+         * If an event became enabled and corresponding status bit is set
+         * then send an SCI to the guest.
+         */
+        if ( (*en & ~en_orig) & *sts )
+            send_guest_global_virq(d, VIRQ_SCI);
     }
 
     return X86EMUL_OKAY;
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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