seabios-add-write-support-to-virtio-blk.patch

From 9664cae167be76a39c4a08c4bc16592c312b404c Mon Sep 17 00:00:00 2001
From: Gleb Natapov <gleb@redhat.com>
Date: Wed, 18 Aug 2010 14:41:57 -0300
Subject: [PATCH] add write support to virtio-blk

RH-Author: Gleb Natapov <gleb@redhat.com>
Message-id: <20100818144157.GE10499@redhat.com>
Patchwork-id: 11398
O-Subject: [PATCH RHEL6 SEABIOS v2] add write support to virtio-blk
Bugzilla: 607500
RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
RH-Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>

Windows XP writes to sector 0 during installation and if write fails it
prints mysterious error.

BZ: 607500
Upstream status: sent upstream

Signed-off-by: Gleb Natapov <gleb@redhat.com>
--

v1->v2:

  Call vring_add_buf correctly for write.

This time I checked that sector 0 is actually changes in the image.

--
			Gleb.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 src/virtio-blk.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/virtio-blk.c b/src/virtio-blk.c
index c7144b5..ddc900a 100644
--- a/src/virtio-blk.c
+++ b/src/virtio-blk.c
@@ -25,13 +25,13 @@ struct virtiodrive_s {
 };
 
 static int
-virtio_blk_read(struct disk_op_s *op)
+virtio_blk_op(struct disk_op_s *op, int write)
 {
     struct drive_s *drive_g = op->drive_g;
     struct virtiodrive_s *vdrive_g = (void*)GET_GLOBAL(drive_g->cntl_info);
     struct vring_virtqueue *vq = GET_FLATPTR(vdrive_g->vq);
     struct virtio_blk_outhdr hdr = {
-        .type = VIRTIO_BLK_T_IN,
+        .type = write ? VIRTIO_BLK_T_OUT : VIRTIO_BLK_T_IN,
         .ioprio = 0,
         .sector = op->lba,
     };
@@ -52,7 +52,11 @@ virtio_blk_read(struct disk_op_s *op)
     };
 
     /* Add to virtqueue and kick host */
-    vring_add_buf(vq, sg, 1, 2, 0, 0);
+    if (write)
+        vring_add_buf(vq, sg, 2, 1, 0, 0);
+    else
+        vring_add_buf(vq, sg, 1, 2, 0, 0);
+
     vring_kick(GET_FLATPTR(vdrive_g->ioaddr), vq, 1);
 
     /* Wait for reply */
@@ -69,9 +73,10 @@ process_virtio_op(struct disk_op_s *op)
 {
     switch (op->command) {
     case CMD_READ:
-        return virtio_blk_read(op);
-    case CMD_FORMAT:
+        return virtio_blk_op(op, 0);
     case CMD_WRITE:
+        return virtio_blk_op(op, 1);
+    case CMD_FORMAT:
         return DISK_RET_EWRITEPROTECT;
     case CMD_RESET:
     case CMD_ISREADY:
-- 
1.7.2.1