diff mbox series

[RFC,v1,20/25] hw/xen: Hook up emulated implementation for event channel operations

Message ID 20230302153435.1170111-21-dwmw2@infradead.org (mailing list archive)
State Superseded
Headers show
Series Enable PV backends with Xen/KVM emulation | expand

Commit Message

David Woodhouse March 2, 2023, 3:34 p.m. UTC 
From: David Woodhouse <dwmw@amazon.co.uk>

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers and xenstore need
to use them.

By what may or may not be an astonishing coincidence, those functions
just *happen* all to have exactly the right function prototypes to slot
into the evtchn_backend_ops table and be called by the PV backends.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 hw/i386/kvm/xen_evtchn.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Comments

Paul Durrant March 7, 2023, 3:50 p.m. UTC | #1 
On 02/03/2023 15:34, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
> 
> We provided the backend-facing evtchn functions very early on as part of
> the core Xen platform support, since things like timers and xenstore need
> to use them.
> 
> By what may or may not be an astonishing coincidence, those functions
> just *happen* all to have exactly the right function prototypes to slot
> into the evtchn_backend_ops table and be called by the PV backends.

It is indeed an amazing coincidence :-)

> 
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   hw/i386/kvm/xen_evtchn.c | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 

Reviewed-by: Paul Durrant <paul@xen.org>
diff mbox series

Patch

diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c
index 886fbf6b3b..98a7b85047 100644
--- a/hw/i386/kvm/xen_evtchn.c
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -34,6 +34,7 @@ 
 #include "hw/pci/msi.h"
 #include "hw/pci/msix.h"
 #include "hw/irq.h"
+#include "hw/xen/xen_backend_ops.h"
 
 #include "xen_evtchn.h"
 #include "xen_overlay.h"
@@ -278,6 +279,17 @@  static const TypeInfo xen_evtchn_info = {
     .class_init    = xen_evtchn_class_init,
 };
 
+static struct evtchn_backend_ops emu_evtchn_backend_ops = {
+    .open = xen_be_evtchn_open,
+    .bind_interdomain = xen_be_evtchn_bind_interdomain,
+    .unbind = xen_be_evtchn_unbind,
+    .close = xen_be_evtchn_close,
+    .get_fd = xen_be_evtchn_fd,
+    .notify = xen_be_evtchn_notify,
+    .unmask = xen_be_evtchn_unmask,
+    .pending = xen_be_evtchn_pending,
+};
+
 static void gsi_assert_bh(void *opaque)
 {
     struct vcpu_info *vi = kvm_xen_get_vcpu_info_hva(0);
@@ -318,6 +330,9 @@  void xen_evtchn_create(void)
     s->nr_pirq_inuse_words = DIV_ROUND_UP(s->nr_pirqs, 64);
     s->pirq_inuse_bitmap = g_new0(uint64_t, s->nr_pirq_inuse_words);
     s->pirq = g_new0(struct pirq_info, s->nr_pirqs);
+
+    /* Set event channel functions for backend drivers to use */
+    xen_evtchn_ops = &emu_evtchn_backend_ops;
 }
 
 void xen_evtchn_connect_gsis(qemu_irq *system_gsis)