From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1L5Oro-00044d-4a for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:12:00 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1L5Orl-00043C-JJ for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:11:59 -0500 Received: from [199.232.76.173] (port=53211 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1L5Orl-000435-Ca for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:11:57 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:57691) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1L5Ork-000504-GG for qemu-devel@nongnu.org; Wed, 26 Nov 2008 13:11:57 -0500 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e33.co.us.ibm.com (8.13.1/8.13.1) with ESMTP id mAQIBImU028940 for ; Wed, 26 Nov 2008 11:11:18 -0700 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mAQIBp0X131092 for ; Wed, 26 Nov 2008 11:11:51 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mAQIBo86024619 for ; Wed, 26 Nov 2008 11:11:51 -0700 From: Hollis Blanchard Date: Wed, 26 Nov 2008 12:11:50 -0600 Message-Id: <1227723110-15128-1-git-send-email-hollisb@us.ibm.com> In-Reply-To: <1227650239-14162-1-git-send-email-aliguori@us.ibm.com> References: <1227650239-14162-1-git-send-email-aliguori@us.ibm.com> Subject: [Qemu-devel] [PATCH 1/1] Virtio block device support Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Avi Kivity From: Anthony Liguori This has been posted before but I believe it now has addressed all outstanding concerns. I'd like to apply it if there are no objections. This patch adds virtio-blk support to QEMU. virtio-blk is a paravirtual disk controller that can achieve good performance when using KVM. Since virtio is based on a scatter/gather API, we don't have a linear buffer for each request. This forces us to allocate a linear buffer since the current block driver API does not have a scatter/gather operation. This allocation can never exceed the maximum data limit on the ring queue so it isn't unbounded. posix-aio cannot support a scatter/gather asynchronous operation so we'll need to introduce our own thread pool to eliminate this limitation. There is work underway to do this. Signed-off-by: Anthony Liguori --- Makefile.target | 2 +- hw/pc.c | 12 ++ hw/pc.h | 4 + hw/virtio-blk.c | 303 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ sysemu.h | 2 +- vl.c | 4 + 6 files changed, 325 insertions(+), 2 deletions(-) create mode 100644 hw/virtio-blk.c diff --git a/Makefile.target b/Makefile.target index f7fc3a2..773b615 100644 --- a/Makefile.target +++ b/Makefile.target @@ -588,7 +588,7 @@ endif #CONFIG_BSD_USER ifndef CONFIG_USER_ONLY OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o -OBJS+=fw_cfg.o virtio.o +OBJS+=fw_cfg.o virtio.o virtio-blk.o ifdef CONFIG_KVM OBJS+=kvm.o kvm-all.o endif diff --git a/hw/pc.c b/hw/pc.c index 1486b68..8651e49 100644 --- a/hw/pc.c +++ b/hw/pc.c @@ -1092,6 +1092,18 @@ static void pc_init1(ram_addr_t ram_size, int vga_ram_size, } } } + + /* Add virtio block devices */ + if (pci_enabled) { + int index; + int unit_id = 0; + + while ((index = drive_get_index(IF_VIRTIO, 0, unit_id)) != -1) { + virtio_blk_init(pci_bus, 0x1AF4, 0x1001, + drives_table[index].bdrv); + unit_id++; + } + } } static void pc_init_pci(ram_addr_t ram_size, int vga_ram_size, diff --git a/hw/pc.h b/hw/pc.h index f156b9e..edbc5e8 100644 --- a/hw/pc.h +++ b/hw/pc.h @@ -152,4 +152,8 @@ void pci_piix4_ide_init(PCIBus *bus, BlockDriverState **hd_table, int devfn, void isa_ne2000_init(int base, qemu_irq irq, NICInfo *nd); +/* virtio-blk.c */ +void *virtio_blk_init(PCIBus *bus, uint16_t vendor, uint16_t device, + BlockDriverState *bs); + #endif diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c new file mode 100644 index 0000000..da87b66 --- /dev/null +++ b/hw/virtio-blk.c @@ -0,0 +1,303 @@ +/* + * Virtio Block Device + * + * Copyright IBM, Corp. 2007 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include "virtio.h" +#include "block.h" +#include "block_int.h" +#include "pc.h" + +/* from Linux's linux/virtio_blk.h */ + +/* The ID for virtio_block */ +#define VIRTIO_ID_BLOCK 2 + +/* Feature bits */ +#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */ +#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */ +#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */ +#define VIRTIO_BLK_F_GEOMETRY 4 /* Indicates support of legacy geometry */ + +struct virtio_blk_config +{ + uint64_t capacity; + uint32_t size_max; + uint32_t seg_max; + uint16_t cylinders; + uint8_t heads; + uint8_t sectors; +} __attribute__((packed)); + +/* These two define direction. */ +#define VIRTIO_BLK_T_IN 0 +#define VIRTIO_BLK_T_OUT 1 + +/* This bit says it's a scsi command, not an actual read or write. */ +#define VIRTIO_BLK_T_SCSI_CMD 2 + +/* Barrier before this op. */ +#define VIRTIO_BLK_T_BARRIER 0x80000000 + +/* This is the first element of the read scatter-gather list. */ +struct virtio_blk_outhdr +{ + /* VIRTIO_BLK_T* */ + uint32_t type; + /* io priority. */ + uint32_t ioprio; + /* Sector (ie. 512 byte offset) */ + uint64_t sector; +}; + +#define VIRTIO_BLK_S_OK 0 +#define VIRTIO_BLK_S_IOERR 1 +#define VIRTIO_BLK_S_UNSUPP 2 + +/* This is the first element of the write scatter-gather list */ +struct virtio_blk_inhdr +{ + unsigned char status; +}; + +typedef struct VirtIOBlock +{ + VirtIODevice vdev; + BlockDriverState *bs; + VirtQueue *vq; +} VirtIOBlock; + +static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev) +{ + return (VirtIOBlock *)vdev; +} + +typedef struct VirtIOBlockReq +{ + VirtIOBlock *dev; + VirtQueueElement elem; + struct virtio_blk_inhdr *in; + struct virtio_blk_outhdr *out; + size_t size; + uint8_t *buffer; +} VirtIOBlockReq; + +static void virtio_blk_rw_complete(void *opaque, int ret) +{ + VirtIOBlockReq *req = opaque; + VirtIOBlock *s = req->dev; + + /* Copy read data to the guest */ + if (!ret && !(req->out->type & VIRTIO_BLK_T_OUT)) { + size_t offset = 0; + int i; + + for (i = 0; i < req->elem.in_num - 1; i++) { + size_t len; + + /* Be pretty defensive wrt malicious guests */ + len = MIN(req->elem.in_sg[i].iov_len, + req->size - offset); + + memcpy(req->elem.in_sg[i].iov_base, + req->buffer + offset, + len); + offset += len; + } + } + + req->in->status = ret ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK; + virtqueue_push(s->vq, &req->elem, req->size + sizeof(*req->in)); + virtio_notify(&s->vdev, s->vq); + + qemu_free(req->buffer); + qemu_free(req); +} + +static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s) +{ + VirtIOBlockReq *req; + + req = qemu_mallocz(sizeof(*req)); + if (req == NULL) + return NULL; + + req->dev = s; + if (!virtqueue_pop(s->vq, &req->elem)) { + qemu_free(req); + return NULL; + } + + return req; +} + +static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) +{ + VirtIOBlock *s = to_virtio_blk(vdev); + VirtIOBlockReq *req; + + while ((req = virtio_blk_get_request(s))) { + int i; + + if (req->elem.out_num < 1 || req->elem.in_num < 1) { + fprintf(stderr, "virtio-blk missing headers\n"); + exit(1); + } + + if (req->elem.out_sg[0].iov_len < sizeof(*req->out) || + req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) { + fprintf(stderr, "virtio-blk header not in correct element\n"); + exit(1); + } + + 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) { + unsigned int len = sizeof(*req->in); + + req->in->status = VIRTIO_BLK_S_UNSUPP; + virtqueue_push(vq, &req->elem, len); + virtio_notify(vdev, vq); + qemu_free(req); + } else if (req->out->type & VIRTIO_BLK_T_OUT) { + size_t offset; + + for (i = 1; i < req->elem.out_num; i++) + req->size += req->elem.out_sg[i].iov_len; + + req->buffer = qemu_memalign(512, req->size); + if (req->buffer == NULL) { + qemu_free(req); + break; + } + + /* We copy the data from the SG list to avoid splitting up the request. This helps + performance a lot until we can pass full sg lists as AIO operations */ + offset = 0; + for (i = 1; i < req->elem.out_num; i++) { + size_t len; + + len = MIN(req->elem.out_sg[i].iov_len, + req->size - offset); + memcpy(req->buffer + offset, + req->elem.out_sg[i].iov_base, + len); + offset += len; + } + + bdrv_aio_write(s->bs, req->out->sector, + req->buffer, + req->size / 512, + virtio_blk_rw_complete, + req); + } else { + for (i = 0; i < req->elem.in_num - 1; i++) + req->size += req->elem.in_sg[i].iov_len; + + req->buffer = qemu_memalign(512, req->size); + if (req->buffer == NULL) { + qemu_free(req); + break; + } + + bdrv_aio_read(s->bs, req->out->sector, + req->buffer, + req->size / 512, + virtio_blk_rw_complete, + req); + } + } + /* + * FIXME: Want to check for completions before returning to guest mode, + * so cached reads and writes are reported as quickly as possible. But + * that should be done in the generic block layer. + */ +} + +static void virtio_blk_reset(VirtIODevice *vdev) +{ + /* + * This should cancel pending requests, but can't do nicely until there + * are per-device request lists. + */ + qemu_aio_flush(); +} + +static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) +{ + VirtIOBlock *s = to_virtio_blk(vdev); + struct virtio_blk_config blkcfg; + uint64_t capacity; + int cylinders, heads, secs; + + bdrv_get_geometry(s->bs, &capacity); + bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs); + stq_raw(&blkcfg.capacity, capacity); + stl_raw(&blkcfg.seg_max, 128 - 2); + stw_raw(&blkcfg.cylinders, cylinders); + blkcfg.heads = heads; + blkcfg.sectors = secs; + memcpy(config, &blkcfg, sizeof(blkcfg)); +} + +static uint32_t virtio_blk_get_features(VirtIODevice *vdev) +{ + return (1 << VIRTIO_BLK_F_SEG_MAX | 1 << VIRTIO_BLK_F_GEOMETRY); +} + +static void virtio_blk_save(QEMUFile *f, void *opaque) +{ + VirtIOBlock *s = opaque; + virtio_save(&s->vdev, f); +} + +static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) +{ + VirtIOBlock *s = opaque; + + if (version_id != 1) + return -EINVAL; + + virtio_load(&s->vdev, f); + + return 0; +} + +void *virtio_blk_init(PCIBus *bus, uint16_t vendor, uint16_t device, + BlockDriverState *bs) +{ + VirtIOBlock *s; + int cylinders, heads, secs; + static int virtio_blk_id; + + s = (VirtIOBlock *)virtio_init_pci(bus, "virtio-blk", vendor, device, + 0, VIRTIO_ID_BLOCK, + 0x01, 0x80, 0x00, + sizeof(struct virtio_blk_config), sizeof(VirtIOBlock)); + if (!s) + return NULL; + + s->vdev.get_config = virtio_blk_update_config; + s->vdev.get_features = virtio_blk_get_features; + s->vdev.reset = virtio_blk_reset; + s->bs = bs; + + bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs); + bdrv_set_geometry_hint(s->bs, cylinders, heads, secs); + + s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output); + + register_savevm("virtio-blk", virtio_blk_id++, 1, + virtio_blk_save, virtio_blk_load, s); + + return s; +} diff --git a/sysemu.h b/sysemu.h index f72ec96..94cffaf 100644 --- a/sysemu.h +++ b/sysemu.h @@ -123,7 +123,7 @@ extern unsigned int nb_prom_envs; #endif typedef enum { - IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD + IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO } BlockInterfaceType; typedef struct DriveInfo { diff --git a/vl.c b/vl.c index e4edf20..33a6fec 100644 --- a/vl.c +++ b/vl.c @@ -2267,6 +2267,9 @@ static int drive_init(struct drive_opt *arg, int snapshot, } else if (!strcmp(buf, "sd")) { type = IF_SD; max_devs = 0; + } else if (!strcmp(buf, "virtio")) { + type = IF_VIRTIO; + max_devs = 0; } else { fprintf(stderr, "qemu: '%s' unsupported bus type '%s'\n", str, buf); return -1; @@ -2474,6 +2477,7 @@ static int drive_init(struct drive_opt *arg, int snapshot, break; case IF_PFLASH: case IF_MTD: + case IF_VIRTIO: break; } if (!file[0]) -- 1.5.6.5