On Wed, Aug 31, 2016 at 05:08:00PM +0900, Namhyung Kim wrote: > The virtio pstore driver provides interface to the pstore subsystem so > that the guest kernel's log/dump message can be saved on the host > machine. Users can access the log file directly on the host, or on the > guest at the next boot using pstore filesystem. It currently deals with > kernel log (printk) buffer only, but we can extend it to have other > information (like ftrace dump) later. > > It supports legacy PCI device using single order-2 page buffer. It uses > two virtqueues - one for (sync) read and another for (async) write. > Since it cannot wait for write finished, it supports up to 128 > concurrent IO. The buffer size is configurable now. > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> > Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> > Cc: Anthony Liguori <aliguori@xxxxxxxxxx> > Cc: Anton Vorontsov <anton@xxxxxxxxxx> > Cc: Colin Cross <ccross@xxxxxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Tony Luck <tony.luck@xxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx > Cc: qemu-devel@xxxxxxxxxx > Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx > Cc: virtio-dev@xxxxxxxxxxxxxxxxxxxx > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx> > --- > drivers/virtio/Kconfig | 10 + > drivers/virtio/Makefile | 1 + > drivers/virtio/virtio_pstore.c | 417 +++++++++++++++++++++++++++++++++++++ > include/uapi/linux/Kbuild | 1 + > include/uapi/linux/virtio_ids.h | 1 + > include/uapi/linux/virtio_pstore.h | 74 +++++++ > 6 files changed, 504 insertions(+) > create mode 100644 drivers/virtio/virtio_pstore.c > create mode 100644 include/uapi/linux/virtio_pstore.h > > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig > index 77590320d44c..8f0e6c796c12 100644 > --- a/drivers/virtio/Kconfig > +++ b/drivers/virtio/Kconfig > @@ -58,6 +58,16 @@ config VIRTIO_INPUT > > If unsure, say M. > > +config VIRTIO_PSTORE > + tristate "Virtio pstore driver" > + depends on VIRTIO > + depends on PSTORE > + ---help--- > + This driver supports virtio pstore devices to save/restore > + panic and oops messages on the host. > + > + If unsure, say M. > + > config VIRTIO_MMIO > tristate "Platform bus driver for memory mapped virtio devices" > depends on HAS_IOMEM && HAS_DMA > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile > index 41e30e3dc842..bee68cb26d48 100644 > --- a/drivers/virtio/Makefile > +++ b/drivers/virtio/Makefile > @@ -5,3 +5,4 @@ virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o > virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o > obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o > obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o > +obj-$(CONFIG_VIRTIO_PSTORE) += virtio_pstore.o > diff --git a/drivers/virtio/virtio_pstore.c b/drivers/virtio/virtio_pstore.c > new file mode 100644 > index 000000000000..ec41f0d2f0b7 > --- /dev/null > +++ b/drivers/virtio/virtio_pstore.c > @@ -0,0 +1,417 @@ > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/pstore.h> > +#include <linux/virtio.h> > +#include <linux/virtio_config.h> > +#include <uapi/linux/virtio_ids.h> > +#include <uapi/linux/virtio_pstore.h> > + > +#define VIRT_PSTORE_ORDER 2 > +#define VIRT_PSTORE_BUFSIZE (4096 << VIRT_PSTORE_ORDER) > +#define VIRT_PSTORE_NR_REQ 128 > + > +struct virtio_pstore { > + struct virtio_device *vdev; > + struct virtqueue *vq[2]; > + struct pstore_info pstore; > + struct virtio_pstore_req req[VIRT_PSTORE_NR_REQ]; > + struct virtio_pstore_res res[VIRT_PSTORE_NR_REQ]; > + unsigned int req_id; > + > + /* Waiting for host to ack */ > + wait_queue_head_t acked; > + int failed; > +}; > + > +#define TYPE_TABLE_ENTRY(_entry) \ > + { PSTORE_TYPE_##_entry, VIRTIO_PSTORE_TYPE_##_entry } > + > +struct type_table { > + int pstore; > + u16 virtio; > +} type_table[] = { > + TYPE_TABLE_ENTRY(DMESG), > +}; > + > +#undef TYPE_TABLE_ENTRY > + > + > +static u16 to_virtio_type(struct virtio_pstore *vps, enum pstore_type_id type) > +{ > + unsigned int i; > + > + for (i = 0; i < ARRAY_SIZE(type_table); i++) { > + if (type == type_table[i].pstore) > + return cpu_to_virtio16(vps->vdev, type_table[i].virtio); Does this pass sparse checks? If yes I'm surprised - this clearly returns a virtio16 type. > + } > + > + return cpu_to_virtio16(vps->vdev, VIRTIO_PSTORE_TYPE_UNKNOWN); > +} > + > +static enum pstore_type_id from_virtio_type(struct virtio_pstore *vps, u16 type) > +{ > + unsigned int i; > + > + for (i = 0; i < ARRAY_SIZE(type_table); i++) { > + if (virtio16_to_cpu(vps->vdev, type) == type_table[i].virtio) > + return type_table[i].pstore; > + } > + > + return PSTORE_TYPE_UNKNOWN; > +} > + > +static void virtpstore_ack(struct virtqueue *vq) > +{ > + struct virtio_pstore *vps = vq->vdev->priv; > + > + wake_up(&vps->acked); > +} > + > +static void virtpstore_check(struct virtqueue *vq) > +{ > + struct virtio_pstore *vps = vq->vdev->priv; > + struct virtio_pstore_res *res; > + unsigned int len; > + > + res = virtqueue_get_buf(vq, &len); > + if (res == NULL) > + return; > + > + if (virtio32_to_cpu(vq->vdev, res->ret) < 0) > + vps->failed = 1; > +} > + > +static void virt_pstore_get_reqs(struct virtio_pstore *vps, > + struct virtio_pstore_req **preq, > + struct virtio_pstore_res **pres) > +{ > + unsigned int idx = vps->req_id++ % VIRT_PSTORE_NR_REQ; > + > + *preq = &vps->req[idx]; > + *pres = &vps->res[idx]; > + > + memset(*preq, 0, sizeof(**preq)); > + memset(*pres, 0, sizeof(**pres)); > +} > + > +static int virt_pstore_open(struct pstore_info *psi) > +{ > + struct virtio_pstore *vps = psi->data; > + struct virtio_pstore_req *req; > + struct virtio_pstore_res *res; > + struct scatterlist sgo[1], sgi[1]; > + struct scatterlist *sgs[2] = { sgo, sgi }; > + unsigned int len; > + > + virt_pstore_get_reqs(vps, &req, &res); > + > + req->cmd = cpu_to_virtio16(vps->vdev, VIRTIO_PSTORE_CMD_OPEN); > + > + sg_init_one(sgo, req, sizeof(*req)); > + sg_init_one(sgi, res, sizeof(*res)); > + virtqueue_add_sgs(vps->vq[0], sgs, 1, 1, vps, GFP_KERNEL); > + virtqueue_kick(vps->vq[0]); > + > + wait_event(vps->acked, virtqueue_get_buf(vps->vq[0], &len)); > + return virtio32_to_cpu(vps->vdev, res->ret); > +} > + > +static int virt_pstore_close(struct pstore_info *psi) > +{ > + struct virtio_pstore *vps = psi->data; > + struct virtio_pstore_req *req = &vps->req[vps->req_id]; > + struct virtio_pstore_res *res = &vps->res[vps->req_id]; > + struct scatterlist sgo[1], sgi[1]; > + struct scatterlist *sgs[2] = { sgo, sgi }; > + unsigned int len; > + > + virt_pstore_get_reqs(vps, &req, &res); > + > + req->cmd = cpu_to_virtio16(vps->vdev, VIRTIO_PSTORE_CMD_CLOSE); > + > + sg_init_one(sgo, req, sizeof(*req)); > + sg_init_one(sgi, res, sizeof(*res)); > + virtqueue_add_sgs(vps->vq[0], sgs, 1, 1, vps, GFP_KERNEL); > + virtqueue_kick(vps->vq[0]); > + > + wait_event(vps->acked, virtqueue_get_buf(vps->vq[0], &len)); > + return virtio32_to_cpu(vps->vdev, res->ret); > +} > + > +static ssize_t virt_pstore_read(u64 *id, enum pstore_type_id *type, > + int *count, struct timespec *time, > + char **buf, bool *compressed, > + ssize_t *ecc_notice_size, > + struct pstore_info *psi) > +{ > + struct virtio_pstore *vps = psi->data; > + struct virtio_pstore_req *req; > + struct virtio_pstore_res *res; > + struct virtio_pstore_fileinfo info; > + struct scatterlist sgo[1], sgi[3]; > + struct scatterlist *sgs[2] = { sgo, sgi }; > + unsigned int len; > + unsigned int flags; > + int ret; > + void *bf; > + > + virt_pstore_get_reqs(vps, &req, &res); > + > + req->cmd = cpu_to_virtio16(vps->vdev, VIRTIO_PSTORE_CMD_READ); > + > + sg_init_one(sgo, req, sizeof(*req)); > + sg_init_table(sgi, 3); > + sg_set_buf(&sgi[0], res, sizeof(*res)); > + sg_set_buf(&sgi[1], &info, sizeof(info)); > + sg_set_buf(&sgi[2], psi->buf, psi->bufsize); > + virtqueue_add_sgs(vps->vq[0], sgs, 1, 1, vps, GFP_KERNEL); > + virtqueue_kick(vps->vq[0]); > + > + wait_event(vps->acked, virtqueue_get_buf(vps->vq[0], &len)); > + if (len < sizeof(*res) + sizeof(info)) > + return -1; > + > + ret = virtio32_to_cpu(vps->vdev, res->ret); > + if (ret < 0) > + return ret; > + > + len = virtio32_to_cpu(vps->vdev, info.len); > + > + bf = kmalloc(len, GFP_KERNEL); > + if (bf == NULL) > + return -ENOMEM; > + > + *id = virtio64_to_cpu(vps->vdev, info.id); > + *type = from_virtio_type(vps, info.type); > + *count = virtio32_to_cpu(vps->vdev, info.count); > + > + flags = virtio32_to_cpu(vps->vdev, info.flags); > + *compressed = flags & VIRTIO_PSTORE_FL_COMPRESSED; > + > + time->tv_sec = virtio64_to_cpu(vps->vdev, info.time_sec); > + time->tv_nsec = virtio32_to_cpu(vps->vdev, info.time_nsec); > + > + memcpy(bf, psi->buf, len); > + *buf = bf; > + > + return len; > +} > + > +static int notrace virt_pstore_write(enum pstore_type_id type, > + enum kmsg_dump_reason reason, > + u64 *id, unsigned int part, int count, > + bool compressed, size_t size, > + struct pstore_info *psi) > +{ > + struct virtio_pstore *vps = psi->data; > + struct virtio_pstore_req *req; > + struct virtio_pstore_res *res; > + struct scatterlist sgo[2], sgi[1]; > + struct scatterlist *sgs[2] = { sgo, sgi }; > + unsigned int flags = compressed ? VIRTIO_PSTORE_FL_COMPRESSED : 0; > + > + if (vps->failed) > + return -1; > + > + *id = vps->req_id; > + virt_pstore_get_reqs(vps, &req, &res); > + > + req->cmd = cpu_to_virtio16(vps->vdev, VIRTIO_PSTORE_CMD_WRITE); > + req->type = to_virtio_type(vps, type); > + req->flags = cpu_to_virtio32(vps->vdev, flags); > + > + sg_init_table(sgo, 2); > + sg_set_buf(&sgo[0], req, sizeof(*req)); > + sg_set_buf(&sgo[1], psi->buf, size); > + sg_init_one(sgi, res, sizeof(*res)); > + virtqueue_add_sgs(vps->vq[1], sgs, 1, 1, vps, GFP_ATOMIC); > + virtqueue_kick(vps->vq[1]); > + > + return 0; > +} > + > +static int virt_pstore_erase(enum pstore_type_id type, u64 id, int count, > + struct timespec time, struct pstore_info *psi) > +{ > + struct virtio_pstore *vps = psi->data; > + struct virtio_pstore_req *req; > + struct virtio_pstore_res *res; > + struct scatterlist sgo[1], sgi[1]; > + struct scatterlist *sgs[2] = { sgo, sgi }; > + unsigned int len; > + > + virt_pstore_get_reqs(vps, &req, &res); > + > + req->cmd = cpu_to_virtio16(vps->vdev, VIRTIO_PSTORE_CMD_ERASE); > + req->type = to_virtio_type(vps, type); > + req->id = cpu_to_virtio64(vps->vdev, id); > + req->count = cpu_to_virtio32(vps->vdev, count); > + > + sg_init_one(sgo, req, sizeof(*req)); > + sg_init_one(sgi, res, sizeof(*res)); > + virtqueue_add_sgs(vps->vq[0], sgs, 1, 1, vps, GFP_KERNEL); > + virtqueue_kick(vps->vq[0]); > + > + wait_event(vps->acked, virtqueue_get_buf(vps->vq[0], &len)); > + return virtio32_to_cpu(vps->vdev, res->ret); > +} > + > +static int virt_pstore_init(struct virtio_pstore *vps) > +{ > + struct pstore_info *psinfo = &vps->pstore; > + int err; > + > + if (!psinfo->bufsize) > + psinfo->bufsize = VIRT_PSTORE_BUFSIZE; > + > + psinfo->buf = alloc_pages_exact(psinfo->bufsize, GFP_KERNEL); > + if (!psinfo->buf) { > + pr_err("cannot allocate pstore buffer\n"); > + return -ENOMEM; > + } > + > + psinfo->owner = THIS_MODULE; > + psinfo->name = "virtio"; > + psinfo->open = virt_pstore_open; > + psinfo->close = virt_pstore_close; > + psinfo->read = virt_pstore_read; > + psinfo->erase = virt_pstore_erase; > + psinfo->write = virt_pstore_write; > + psinfo->flags = PSTORE_FLAGS_FRAGILE; > + > + psinfo->data = vps; > + spin_lock_init(&psinfo->buf_lock); > + > + err = pstore_register(psinfo); > + if (err) > + kfree(psinfo->buf); > + > + return err; > +} > + > +static int virt_pstore_exit(struct virtio_pstore *vps) > +{ > + struct pstore_info *psinfo = &vps->pstore; > + > + pstore_unregister(psinfo); > + > + free_pages_exact(psinfo->buf, psinfo->bufsize); > + psinfo->buf = NULL; > + psinfo->bufsize = 0; > + > + return 0; > +} > + > +static int virtpstore_init_vqs(struct virtio_pstore *vps) > +{ > + vq_callback_t *callbacks[] = { virtpstore_ack, virtpstore_check }; > + const char *names[] = { "pstore_read", "pstore_write" }; > + > + return vps->vdev->config->find_vqs(vps->vdev, 2, vps->vq, > + callbacks, names); > +} > + > +static void virtpstore_init_config(struct virtio_pstore *vps) > +{ > + u32 bufsize; > + > + virtio_cread(vps->vdev, struct virtio_pstore_config, bufsize, &bufsize); > + > + vps->pstore.bufsize = PAGE_ALIGN(bufsize); > +} > + > +static void virtpstore_confirm_config(struct virtio_pstore *vps) > +{ > + u32 bufsize = vps->pstore.bufsize; > + > + virtio_cwrite(vps->vdev, struct virtio_pstore_config, bufsize, > + &bufsize); > +} > + > +static int virtpstore_probe(struct virtio_device *vdev) > +{ > + struct virtio_pstore *vps; > + int err; > + > + if (!vdev->config->get) { > + dev_err(&vdev->dev, "driver init: config access disabled\n"); > + return -EINVAL; > + } > + > + vdev->priv = vps = kzalloc(sizeof(*vps), GFP_KERNEL); > + if (!vps) { > + err = -ENOMEM; > + goto out; > + } > + vps->vdev = vdev; > + > + err = virtpstore_init_vqs(vps); > + if (err < 0) > + goto out_free; > + > + virtpstore_init_config(vps); > + > + err = virt_pstore_init(vps); > + if (err) > + goto out_del_vq; > + > + virtpstore_confirm_config(vps); > + > + init_waitqueue_head(&vps->acked); > + > + virtio_device_ready(vdev); > + > + dev_info(&vdev->dev, "driver init: ok (bufsize = %luK, flags = %x)\n", > + vps->pstore.bufsize >> 10, vps->pstore.flags); > + > + return 0; > + > +out_del_vq: > + vdev->config->del_vqs(vdev); > +out_free: > + kfree(vps); > +out: > + dev_err(&vdev->dev, "driver init: failed with %d\n", err); > + return err; > +} > + > +static void virtpstore_remove(struct virtio_device *vdev) > +{ > + struct virtio_pstore *vps = vdev->priv; > + > + virt_pstore_exit(vps); > + > + /* Now we reset the device so we can clean up the queues. */ > + vdev->config->reset(vdev); > + > + vdev->config->del_vqs(vdev); > + > + kfree(vps); > +} > + > +static unsigned int features[] = { > +}; > + > +static struct virtio_device_id id_table[] = { > + { VIRTIO_ID_PSTORE, VIRTIO_DEV_ANY_ID }, > + { 0 }, > +}; > + > +static struct virtio_driver virtio_pstore_driver = { > + .driver.name = KBUILD_MODNAME, > + .driver.owner = THIS_MODULE, > + .feature_table = features, > + .feature_table_size = ARRAY_SIZE(features), > + .id_table = id_table, > + .probe = virtpstore_probe, > + .remove = virtpstore_remove, > +}; > + > +module_virtio_driver(virtio_pstore_driver); > +MODULE_DEVICE_TABLE(virtio, id_table); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Namhyung Kim <namhyung@xxxxxxxxxx>"); > +MODULE_DESCRIPTION("Virtio pstore driver"); > diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild > index 6d4e92ccdc91..9bbb1554d8b2 100644 > --- a/include/uapi/linux/Kbuild > +++ b/include/uapi/linux/Kbuild > @@ -449,6 +449,7 @@ header-y += virtio_ids.h > header-y += virtio_input.h > header-y += virtio_net.h > header-y += virtio_pci.h > +header-y += virtio_pstore.h > header-y += virtio_ring.h > header-y += virtio_rng.h > header-y += virtio_scsi.h > diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h > index 77925f587b15..c72a9ab588c0 100644 > --- a/include/uapi/linux/virtio_ids.h > +++ b/include/uapi/linux/virtio_ids.h > @@ -41,5 +41,6 @@ > #define VIRTIO_ID_CAIF 12 /* Virtio caif */ > #define VIRTIO_ID_GPU 16 /* virtio GPU */ > #define VIRTIO_ID_INPUT 18 /* virtio input */ > +#define VIRTIO_ID_PSTORE 22 /* virtio pstore */ > > #endif /* _LINUX_VIRTIO_IDS_H */ > diff --git a/include/uapi/linux/virtio_pstore.h b/include/uapi/linux/virtio_pstore.h > new file mode 100644 > index 000000000000..f4b0d204d8ae > --- /dev/null > +++ b/include/uapi/linux/virtio_pstore.h > @@ -0,0 +1,74 @@ > +#ifndef _LINUX_VIRTIO_PSTORE_H > +#define _LINUX_VIRTIO_PSTORE_H > +/* This header is BSD licensed so anyone can use the definitions to implement > + * compatible drivers/servers. > + * > + * Redistribution and use in source and binary forms, with or without > + * modification, are permitted provided that the following conditions > + * are met: > + * 1. Redistributions of source code must retain the above copyright > + * notice, this list of conditions and the following disclaimer. > + * 2. Redistributions in binary form must reproduce the above copyright > + * notice, this list of conditions and the following disclaimer in the > + * documentation and/or other materials provided with the distribution. > + * 3. Neither the name of IBM nor the names of its contributors > + * may be used to endorse or promote products derived from this software > + * without specific prior written permission. > + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND > + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE > + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE > + * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE > + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL > + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS > + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) > + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT > + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY > + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF > + * SUCH DAMAGE. */ > +#include <linux/types.h> > +#include <linux/virtio_types.h> > + > +#define VIRTIO_PSTORE_CMD_NULL 0 > +#define VIRTIO_PSTORE_CMD_OPEN 1 > +#define VIRTIO_PSTORE_CMD_READ 2 > +#define VIRTIO_PSTORE_CMD_WRITE 3 > +#define VIRTIO_PSTORE_CMD_ERASE 4 > +#define VIRTIO_PSTORE_CMD_CLOSE 5 > + > +#define VIRTIO_PSTORE_TYPE_UNKNOWN 0 > +#define VIRTIO_PSTORE_TYPE_DMESG 1 > + > +#define VIRTIO_PSTORE_FL_COMPRESSED 1 > + > +struct virtio_pstore_req { > + __virtio16 cmd; > + __virtio16 type; > + __virtio32 flags; > + __virtio64 id; > + __virtio32 count; > + __virtio32 reserved; > +}; > + > +struct virtio_pstore_res { > + __virtio16 cmd; > + __virtio16 type; > + __virtio32 ret; > +}; Is there a reason to support legacy endian-ness? If not, you can just use __le formats. > +struct virtio_pstore_fileinfo { > + __virtio64 id; > + __virtio32 count; > + __virtio16 type; > + __virtio16 unused; > + __virtio32 flags; > + __virtio32 len; > + __virtio64 time_sec; > + __virtio32 time_nsec; > + __virtio32 reserved; > +}; > + > +struct virtio_pstore_config { > + __virtio32 bufsize; > +}; > + > +#endif /* _LINUX_VIRTIO_PSTORE_H */ > -- > 2.9.3 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization