vmx: reset virtio queue state on device reset

when a virtio device gets reset, we have to also reset the device
shadow indices: availableidx and usedidx. for extra safetly,
we also reset the buffer descriptor table addresses.

this is accomplished by adding a vioqreset(VIOQueue*) function
that brings the queue to its initial reset state.

this fixes non functional ethernet after reboot(8).

1 files changed, 13 insertions, 0 deletions

diff --git a/sys/src/cmd/vmx/virtio.c b/sys/src/cmd/vmx/virtio.c
index 6451eeef5..da0558320 100644
--- a/sys/src/cmd/vmx/virtio.c
+++ b/sys/src/cmd/vmx/virtio.c
@@ -311,6 +311,17 @@ vioqaddrset(VIOQueue *q, u64int addr)
 }
 
 static void
+vioqreset(VIOQueue *q)
+{
+	q->desc = nil;
+	q->avail = nil;
+	q->used = nil;
+	q->addr = 0;
+	q->availidx = 0;
+	q->usedidx = 0;
+}
+
+static void
 viodevstatset(VIODev *v, u32int val)
 {
 	int i;
@@ -325,6 +336,7 @@ viodevstatset(VIODev *v, u32int val)
 			qlock(&v->qu[i]);
 			while(v->qu[i].livebuf > 0)
 				rsleep(&v->qu[i].livebufrend);
+			vioqreset(&v->qu[i]);
 			qunlock(&v->qu[i]);
 		}
 	}else{
@@ -396,6 +408,7 @@ mkvioqueue(VIODev *d, int sz, void (*fn)(VIOQueue*))
 	q->size = sz;
 	q->d = d;
 	q->notify = fn;
+	vioqreset(q);
 	return q;
 }