From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MiDKM-00048n-E1 for qemu-devel@nongnu.org; Mon, 31 Aug 2009 16:18:10 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MiDKH-00046S-Up for qemu-devel@nongnu.org; Mon, 31 Aug 2009 16:18:09 -0400 Received: from [199.232.76.173] (port=51923 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MiDKH-00046N-G9 for qemu-devel@nongnu.org; Mon, 31 Aug 2009 16:18:05 -0400 Received: from verein.lst.de ([213.95.11.210]:33979) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA1:24) (Exim 4.60) (envelope-from ) id 1MiDKH-0001JN-0y for qemu-devel@nongnu.org; Mon, 31 Aug 2009 16:18:05 -0400 From: Christoph Hellwig Date: Mon, 31 Aug 2009 22:18:02 +0200 Message-ID: <20090831201802.GD4874@lst.de> References: <20090831201627.GA4811@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090831201627.GA4811@lst.de> Subject: [Qemu-devel] [PATCH 4/4] virtio-blk: add volatile writecache feature List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: rusty@rustcorp.com.au Add a new VIRTIO_BLK_F_WCACHE feature to virtio-blk to indicate that we have a volatile write cache that needs controlled flushing. Implement a VIRTIO_BLK_T_FLUSH operation to flush it. Signed-off-by: Christoph Hellwig Index: qemu-kvm/hw/virtio-blk.c =================================================================== --- qemu-kvm.orig/hw/virtio-blk.c +++ qemu-kvm/hw/virtio-blk.c @@ -129,6 +129,13 @@ static void virtio_blk_rw_complete(void virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); } +static void virtio_blk_flush_complete(void *opaque, int ret) +{ + VirtIOBlockReq *req = opaque; + + virtio_blk_req_complete(req, ret ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK); +} + static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) { VirtIOBlockReq *req = qemu_mallocz(sizeof(*req)); @@ -252,6 +259,16 @@ static void virtio_blk_handle_scsi(VirtI } #endif /* __linux__ */ +static void virtio_blk_handle_flush(VirtIOBlockReq *req) +{ + BlockDriverAIOCB *acb; + + acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req); + if (!acb) { + virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); + } +} + static void virtio_blk_handle_write(VirtIOBlockReq *req) { BlockDriverAIOCB *acb; @@ -294,7 +311,9 @@ static void virtio_blk_handle_output(Vir req->out = (void *)req->elem.out_sg[0].iov_base; req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base; - if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) { + if (req->out->type & VIRTIO_BLK_T_FLUSH) { + virtio_blk_handle_flush(req); + } else if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) { virtio_blk_handle_scsi(req); } else if (req->out->type & VIRTIO_BLK_T_OUT) { qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1], @@ -382,6 +401,9 @@ static uint32_t virtio_blk_get_features( features |= (1 << VIRTIO_BLK_F_SEG_MAX); features |= (1 << VIRTIO_BLK_F_GEOMETRY); + + if (bdrv_enable_write_cache(s->bs)) + features |= (1 << VIRTIO_BLK_F_WCACHE); #ifdef __linux__ features |= (1 << VIRTIO_BLK_F_SCSI); #endif Index: qemu-kvm/hw/virtio-blk.h =================================================================== --- qemu-kvm.orig/hw/virtio-blk.h +++ qemu-kvm/hw/virtio-blk.h @@ -31,6 +31,7 @@ #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ #define VIRTIO_BLK_F_IDENTIFY 8 /* ATA IDENTIFY supported */ +#define VIRTIO_BLK_F_WCACHE 9 /* write cache enabled */ #define VIRTIO_BLK_ID_LEN 256 /* length of identify u16 array */ #define VIRTIO_BLK_ID_SN 10 /* start of char * serial# */ @@ -55,6 +56,9 @@ struct virtio_blk_config /* This bit says it's a scsi command, not an actual read or write. */ #define VIRTIO_BLK_T_SCSI_CMD 2 +/* Flush the volatile write cache */ +#define VIRTIO_BLK_T_FLUSH 4 + /* Barrier before this op. */ #define VIRTIO_BLK_T_BARRIER 0x80000000