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ethervirtio: feature negotiation, allow setting mac address, dont read isr from ifstatus, avoid indirection

- properly negotiate Fctrlrx feature bit for promisc and multicast.
- allow setting mac address with ea= option from plan9.ini
- dont read the isr register from ifstats() as it has the side effect of reseting isr status
- embedd the Vqueue array in the Ctlr structure avoiding indirection
- add a interrupt counter Vqueue.nintr for statistical purposes
- only read network status register if the feature has been negotiated
- change name to "virtio" as "ethervirtio" is kind of redundant

--- a/sys/src/9/pc/ethervirtio.c

+++ b/sys/src/9/pc/ethervirtio.c

@@ -48,6 +48,7 @@

 	Fmac = (1<<5),

 	Fstatus = (1<<16),

 	Fctrlvq = (1<<17),

+	Fctrlrx = (1<<18),

 	/* vring used flags */

 	Unonotify = 1,

@@ -134,6 +135,8 @@

 	Vused	*usedent;

 	u16int	*usedevent;

 	u16int	lastused;

+

+	uint	nintr;

 };

 struct Ctlr {

@@ -153,10 +156,7 @@

 	int	nqueue;

 	/* virtioether has 3 queues: rx, tx and ctl */

-	Vqueue	*queue[3];

-

-	/* MAC address */

-	uchar	ea[Eaddrlen];

+	Vqueue	queue[3];

 };

 static Ctlr *ctlrhead;

@@ -182,7 +182,7 @@

 	edev = v;

 	ctlr = edev->ctlr;

-	q = ctlr->queue[Vtxq];

+	q = &ctlr->queue[Vtxq];

 	header = smalloc(VheaderSize);

 	blocks = smalloc(sizeof(Block*) * (q->qsize/2));

@@ -256,7 +256,7 @@

 	edev = v;

 	ctlr = edev->ctlr;

-	q = ctlr->queue[Vrxq];

+	q = &ctlr->queue[Vrxq];

 	header = smalloc(VheaderSize);

 	blocks = smalloc(sizeof(Block*) * (q->qsize/2));

@@ -327,8 +327,8 @@

 	int i;

 	ctlr = edev->ctlr;

-	q = ctlr->queue[Vctlq];

-	if(q == nil || q->qsize < 3)

+	q = &ctlr->queue[Vctlq];

+	if(q->qsize < 3)

 		return -1;

 	qlock(&ctlr->ctllock);

@@ -388,9 +388,11 @@

 	ctlr = edev->ctlr;

 	if(inb(ctlr->port+Qisr) & 1){

 		for(i = 0; i < ctlr->nqueue; i++){

-			q = ctlr->queue[i];

-			if(vhasroom(q))

+			q = &ctlr->queue[i];

+			if(vhasroom(q)){

+				q->nintr++;

 				wakeup(q);

+			}

 		}

 	}

 }

@@ -433,13 +435,13 @@

 	l = snprint(p, READSTR, "devfeat %32.32lub\n", ctlr->feat);

 	l += snprint(p+l, READSTR-l, "drvfeat %32.32lub\n", inl(ctlr->port+Qdrvfeat));

 	l += snprint(p+l, READSTR-l, "devstatus %8.8ub\n", inb(ctlr->port+Qstatus));

-	l += snprint(p+l, READSTR-l, "isr %8.8ub\n",  inb(ctlr->port+Qisr));

-	l += snprint(p+l, READSTR-l, "netstatus %8.8ub\n",  inb(ctlr->port+Qnetstatus));

+	if(ctlr->feat & Fstatus)

+		l += snprint(p+l, READSTR-l, "netstatus %8.8ub\n",  inb(ctlr->port+Qnetstatus));

 	for(i = 0; i < ctlr->nqueue; i++){

-		q = ctlr->queue[i];

-		l += snprint(p+l, READSTR-l, "vq%d %#p size %d avail->idx %d used->idx %d lastused %hud\n",

-			i, q, q->qsize, q->avail->idx, q->used->idx, q->lastused);

+		q = &ctlr->queue[i];

+		l += snprint(p+l, READSTR-l, "vq%d %#p size %d avail->idx %d used->idx %d lastused %hud nintr %ud\n",

+			i, q, q->qsize, q->avail->idx, q->used->idx, q->lastused, q->nintr);

 	}

 	n = readstr(offset, a, n, p);

@@ -483,22 +485,19 @@

 		+ VPGROUND(sizeof(u16int)*3 + VusedSize*size);

 }

-static Vqueue*

-mkqueue(int size)

+static int

+initqueue(Vqueue *q, int size)

 {

-	Vqueue *q;

 	uchar *p;

 	/* §2.4: Queue Size value is always a power of 2 and <= 32768 */

 	assert(!(size & (size - 1)) && size <= 32768);

-	q = mallocz(sizeof(Vqueue), 1);

 	p = mallocalign(queuesize(size), VBY2PG, 0, 0);

-	if(p == nil || q == nil){

+	if(p == nil){

 		print("ethervirtio: no memory for Vqueue\n");

 		free(p);

-		free(q);

-		return nil;

+		return -1;

 	}

 	q->desc = (void*)p;

@@ -521,13 +520,9 @@

 	q->qmask = q->qsize - 1;

 	q->lastused = q->avail->idx = q->used->idx = 0;

-

-	/* disable interrupts

-	 * virtio spec says we still get interrupts if

-	 * VnotifyEmpty is set in Drvfeat */

 	q->used->flags |= Rnointerrupt;

-	return q;

+	return 0;

 }

 static Ctlr*

@@ -552,13 +547,12 @@

 		/* non-transitional device will have typ+0x40 */

 		if(pcicfgr16(p, 0x2E) != typ)

 			continue;

-		if((c = malloc(sizeof(Ctlr))) == nil){

+		if((c = mallocz(sizeof(Ctlr), 1)) == nil){

 			print("ethervirtio: no memory for Ctlr\n");

 			break;

 		}

 		c->port = p->mem[0].bar & ~0x1;

-

 		if(ioalloc(c->port, p->mem[0].size, 0, "ethervirtio") < 0){

 			print("ethervirtio: port %ux in use\n", c->port);

 			free(c);

@@ -571,53 +565,25 @@

 		/* §3.1.2 Legacy Device Initialization */

 		outb(c->port+Qstatus, 0);

-

 		outb(c->port+Qstatus, Sacknowledge|Sdriver);

+		/* negotiate feature bits */

 		c->feat = inl(c->port+Qdevfeat);

+		outl(c->port+Qdrvfeat, c->feat & (Fmac|Fstatus|Fctrlvq|Fctrlrx));

-		if((c->feat & (Fmac|Fstatus|Fctrlvq)) != (Fmac|Fstatus|Fctrlvq)){

-			print("ethervirtio: feature mismatch %32.32lub\n", c->feat);

-			outb(c->port+Qstatus, Sfailed);

-			iofree(c->port);

-			free(c);

-			continue;

-		}

-

-		outl(c->port+Qdrvfeat, Fmac|Fstatus|Fctrlvq);

-

-		/* part of the 1.0 spec, not used in legacy */

-		/*

-		outb(vd->port+Status, inb(vd->port+Status) | FeatureOk);

-		i = inb(vd->port+Status);

-		if(!(i & FeatureOk)){

-			print("ethervirtio: feature mismatch %32.32lub\n", vd->feat);

-			outb(vd->port+Status, Failed);

-			iofree(vd->port);

-			free(vd);

-			continue;

-		}

-		*/

-

 		/* §4.1.5.1.4 Virtqueue Configuration */

 		for(i=0; i<nelem(c->queue); i++){

 			outs(c->port+Qselect, i);

 			n = ins(c->port+Qsize);

-			if(n == 0 || (n & (n-1)) != 0){

-				c->queue[i] = nil;

+			if(n == 0 || (n & (n-1)) != 0)

 				break;

-			}

-			if((c->queue[i] = mkqueue(n)) == nil)

+			if(initqueue(&c->queue[i], n) < 0)

 				break;

 			coherence();

-			outl(c->port+Qaddr, PADDR(c->queue[i]->desc)/VBY2PG);

+			outl(c->port+Qaddr, PADDR(c->queue[i].desc)/VBY2PG);

 		}

-		c->nqueue = i;

+		c->nqueue = i;		

-		/* read virtio mac */

-		for(i = 0; i < Eaddrlen; i++)

-			c->ea[i] = inb(c->port+Qmac+i);

-

 		if(h == nil)

 			h = c;

 		else

@@ -632,7 +598,9 @@

 static int

 reset(Ether* edev)

 {

+	static uchar zeros[Eaddrlen];

 	Ctlr *ctlr;

+	int i;

 	if(ctlrhead == nil) {

 		ctlrhead = pciprobe(1);

@@ -657,19 +625,26 @@

 	edev->mbps = 1000;

 	edev->link = 1;

-	memmove(edev->ea, ctlr->ea, Eaddrlen);

+	if((ctlr->feat & Fmac) != 0 && memcmp(edev->ea, zeros, Eaddrlen) == 0){

+		for(i = 0; i < Eaddrlen; i++)

+			edev->ea[i] = inb(ctlr->port+Qmac+i);

+	} else {

+		for(i = 0; i < Eaddrlen; i++)

+			outb(ctlr->port+Qmac+i, edev->ea[i]);

+	}

 	edev->arg = edev;

 	edev->attach = attach;

 	edev->shutdown = shutdown;

-

 	edev->interrupt = interrupt;

-

 	edev->ifstat = ifstat;

-	edev->multicast = multicast;

-	edev->promiscuous = promiscuous;

+	if((ctlr->feat & (Fctrlvq|Fctrlrx)) == (Fctrlvq|Fctrlrx)){

+		edev->multicast = multicast;

+		edev->promiscuous = promiscuous;

+	}

+

 	return 0;

 }

@@ -676,6 +651,6 @@

 void

 ethervirtiolink(void)

 {

-	addethercard("ethervirtio", reset);

+	addethercard("virtio", reset);

 }