kvm tools: Use ioeventfd in virtio-9p

Use ioeventfd to receive virt queue notifications within virtio-9p.
This should prevent exits on 9p commands.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/virtio/9p.c b/tools/kvm/virtio/9p.c
index d4263d26057990ca23d9cb4b4d1e21c34ddb03f0..3158cbc29f2e3fbdcb11accde80ff9ce45591e25 100644 (file)
--- a/tools/kvm/virtio/9p.c
+++ b/tools/kvm/virtio/9p.c
@@ -8,6 +8,7 @@
 #include "kvm/pci.h"
 #include "kvm/threadpool.h"
 #include "kvm/irq.h"
+#include "kvm/ioeventfd.h"
 
 #include <linux/virtio_ring.h>
 #include <linux/virtio_9p.h>
@@ -605,12 +606,20 @@ static void virtio_p9_do_io(struct kvm *kvm, void *param)
        }
 }
 
+static void ioevent_callback(struct kvm *kvm, void *param)
+{
+       struct p9_dev_job *job = param;
+
+       thread_pool__do_job(job->job_id);
+}
+
 static bool virtio_p9_pci_io_out(struct ioport *ioport, struct kvm *kvm,
                                 u16 port, void *data, int size, u32 count)
 {
        unsigned long offset;
        bool ret = true;
        struct p9_dev  *p9dev;
+       struct ioevent ioevent;
 
        p9dev = ioport->priv;
        offset = port - p9dev->base_addr;
@@ -637,6 +646,19 @@ static bool virtio_p9_pci_io_out(struct ioport *ioport, struct kvm *kvm,
                        .p9dev                  = p9dev,
                };
                job->job_id = thread_pool__add_job(kvm, virtio_p9_do_io, job);
+
+               ioevent = (struct ioevent) {
+                       .io_addr                = p9dev->base_addr + VIRTIO_PCI_QUEUE_NOTIFY,
+                       .io_len                 = sizeof(u16),
+                       .fn                     = ioevent_callback,
+                       .datamatch              = p9dev->queue_selector,
+                       .fn_ptr                 = &p9dev->jobs[p9dev->queue_selector],
+                       .fn_kvm                 = kvm,
+                       .fd                     = eventfd(0, 0),
+               };
+
+               ioeventfd__add_event(&ioevent);
+
                break;
        }
        case VIRTIO_PCI_QUEUE_SEL:
@@ -644,6 +666,7 @@ static bool virtio_p9_pci_io_out(struct ioport *ioport, struct kvm *kvm,
                break;
        case VIRTIO_PCI_QUEUE_NOTIFY: {
                u16 queue_index;
+
                queue_index             = ioport__read16(data);
                thread_pool__do_job(p9dev->jobs[queue_index].job_id);
                break;