From 87b0ff64b21a560d6ea7c1816acbcfd7c31dff12 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Fri, 29 Mar 2024 13:36:48 -0300
Subject: [PATCH] virtio: feature negotiation

---
 kernel-src/include/kernel/virtio.h |  3 +++
 kernel-src/io/block/vioblk.c       |  5 +----
 kernel-src/io/virtio.c             | 24 +++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/kernel-src/include/kernel/virtio.h b/kernel-src/include/kernel/virtio.h
index b3a51e05..e53ba60d 100644
--- a/kernel-src/include/kernel/virtio.h
+++ b/kernel-src/include/kernel/virtio.h
@@ -46,9 +46,12 @@ typedef struct {
 void virtio_init();
 size_t virtio_queuesize(viodevice_t *viodevice, int queue);
 void virtio_enablequeue(viodevice_t *viodevice, int queue);
+uint64_t virtio_negotiatefeatures(viodevice_t *viodevice, uint64_t features);
 void *virtio_createqueue(viodevice_t *viodevice, vioqueue_t *vioqueue, int queue, size_t size, int msix);
 void virtio_enabledevice(viodevice_t *viodevice);
 
+#define VIO_FEATURE_VERSION_1 (1l << 32)
+
 #define VIO_CONFIG_STATUS_SET(x, v) (x)->config->status |= v
 #define VIO_CONFIG_STATUS_ACK 1
 #define VIO_CONFIG_STATUS_DRIVER 2
diff --git a/kernel-src/io/block/vioblk.c b/kernel-src/io/block/vioblk.c
index 7576b152..4e7341d7 100644
--- a/kernel-src/io/block/vioblk.c
+++ b/kernel-src/io/block/vioblk.c
@@ -151,10 +151,7 @@ int vioblk_newdevice(viodevice_t *viodevice) {
 	pci_initmsix(viodevice->e);
 
 	// TODO support several queues
-	// no extra features will be used yet
-	VIO_CONFIG_STATUS_SET(viodevice, VIO_CONFIG_STATUS_FEATURESOK);
-	if ((viodevice->config->status & VIO_CONFIG_STATUS_FEATURESOK) == 0)
-		return 1;
+	__assert(virtio_negotiatefeatures(viodevice, VIO_FEATURE_VERSION_1) == VIO_FEATURE_VERSION_1);
 
 	// initialize device object
 	vioblkdev_t *blkdev = alloc(sizeof(vioblkdev_t));
diff --git a/kernel-src/io/virtio.c b/kernel-src/io/virtio.c
index 3f2d0508..3af4b385 100644
--- a/kernel-src/io/virtio.c
+++ b/kernel-src/io/virtio.c
@@ -17,9 +17,11 @@ static char *devname[] = {
 
 void vioblk_init();
 int vioblk_newdevice(viodevice_t *);
+void vionet_init();
+int vionet_newdevice(viodevice_t *);
 
 static int (*drivedevice[]) (viodevice_t *) = {
-	NULL,
+	vionet_newdevice,
 	vioblk_newdevice
 };
 
@@ -33,6 +35,24 @@ void virtio_enablequeue(viodevice_t *viodevice, int queue) {
 	viodevice->config->queueenable = 1;
 }
 
+uint64_t virtio_negotiatefeatures(viodevice_t *viodevice, uint64_t features) {
+	viodevice->config->devicefeatureselect = 0;
+	uint64_t offered = viodevice->config->devicefeature;
+	viodevice->config->devicefeatureselect = 1;
+	offered |= (uint64_t)viodevice->config->devicefeature << 32;
+	uint64_t negotiable = features & offered;
+
+	viodevice->config->driverfeatureselect = 0;
+	viodevice->config->driverfeature = negotiable & 0xffffffff;
+	viodevice->config->driverfeatureselect = 1;
+	viodevice->config->driverfeature = (negotiable >> 32) & 0xffffffff;
+
+	VIO_CONFIG_STATUS_SET(viodevice, VIO_CONFIG_STATUS_FEATURESOK);
+	__assert(viodevice->config->status & VIO_CONFIG_STATUS_FEATURESOK);
+
+	return negotiable;
+}
+
 static uint16_t *virtio_queuenotifyaddress(viodevice_t *viodevice, int queue) {
        viodevice->config->queueselect = queue;
        return (uint16_t *)((uintptr_t)viodevice->notify + viodevice->config->queuenotifyoffset * viodevice->notifymultiplier);
@@ -79,6 +99,7 @@ void virtio_enabledevice(viodevice_t *viodevice) {
 static void virtio_newdevice(pcienum_t *e) {
 	pci_setcommand(e, PCI_COMMAND_MMIO, 1);
 	pci_setcommand(e, PCI_COMMAND_IO, 0);
+	pci_setcommand(e, PCI_COMMAND_BUSMASTER, 1);
 	pci_setcommand(e, PCI_COMMAND_IRQDISABLE, 1);
 
 	int devtype = e->deviceid - VIRTIO_DEVICE_MIN;
@@ -146,6 +167,7 @@ static void virtio_newdevice(pcienum_t *e) {
 
 void virtio_init() {
 	vioblk_init();
+	vionet_init();
 
 	for (int dev = VIRTIO_DEVICE_MIN; dev <= VIRTIO_DEVICE_MAX; ++dev) {
 		int i = 0;