[PATCH 3/3] kvmtool: Implement virtio-pstore device
From: Namhyung Kim
Date: Mon Jul 18 2016 - 00:39:04 EST
Add virtio pstore device to allow kernel log messages saved on the
host. With this patch, it will save the log files under directory given
by --pstore option.
$ lkvm run --pstore=dir-xx
(guest) # echo c > /proc/sysrq-trigger
$ ls dir-xx
dmesg-0.enc.z dmesg-1.enc.z
The log files are usually compressed using zlib. User can easily see
the messages on the host or on the guest (using pstore filesystem).
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <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: kvm@xxxxxxxxxxxxxxx
Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
Makefile | 1 +
builtin-run.c | 2 +
include/kvm/kvm-config.h | 1 +
include/kvm/virtio-pci-dev.h | 2 +
include/kvm/virtio-pstore.h | 31 ++++
include/linux/virtio_ids.h | 1 +
virtio/pstore.c | 359 +++++++++++++++++++++++++++++++++++++++++++
7 files changed, 397 insertions(+)
create mode 100644 include/kvm/virtio-pstore.h
create mode 100644 virtio/pstore.c
diff --git a/Makefile b/Makefile
index 1f0196f..d7462b9 100644
--- a/Makefile
+++ b/Makefile
@@ -67,6 +67,7 @@ OBJS += virtio/net.o
OBJS += virtio/rng.o
OBJS += virtio/balloon.o
OBJS += virtio/pci.o
+OBJS += virtio/pstore.o
OBJS += disk/blk.o
OBJS += disk/qcow.o
OBJS += disk/raw.o
diff --git a/builtin-run.c b/builtin-run.c
index 72b878d..08c12dd 100644
--- a/builtin-run.c
+++ b/builtin-run.c
@@ -128,6 +128,8 @@ void kvm_run_set_wrapper_sandbox(void)
" rootfs"), \
OPT_STRING('\0', "hugetlbfs", &(cfg)->hugetlbfs_path, "path", \
"Hugetlbfs path"), \
+ OPT_STRING('\0', "pstore", &(cfg)->pstore_path, "path", \
+ "pstore data path"), \
\
OPT_GROUP("Kernel options:"), \
OPT_STRING('k', "kernel", &(cfg)->kernel_filename, "kernel", \
diff --git a/include/kvm/kvm-config.h b/include/kvm/kvm-config.h
index 386fa8c..42b7651 100644
--- a/include/kvm/kvm-config.h
+++ b/include/kvm/kvm-config.h
@@ -45,6 +45,7 @@ struct kvm_config {
const char *hugetlbfs_path;
const char *custom_rootfs_name;
const char *real_cmdline;
+ const char *pstore_path;
struct virtio_net_params *net_params;
bool single_step;
bool vnc;
diff --git a/include/kvm/virtio-pci-dev.h b/include/kvm/virtio-pci-dev.h
index 48ae018..4339d94 100644
--- a/include/kvm/virtio-pci-dev.h
+++ b/include/kvm/virtio-pci-dev.h
@@ -15,6 +15,7 @@
#define PCI_DEVICE_ID_VIRTIO_BLN 0x1005
#define PCI_DEVICE_ID_VIRTIO_SCSI 0x1008
#define PCI_DEVICE_ID_VIRTIO_9P 0x1009
+#define PCI_DEVICE_ID_VIRTIO_PSTORE 0x100a
#define PCI_DEVICE_ID_VESA 0x2000
#define PCI_DEVICE_ID_PCI_SHMEM 0x0001
@@ -34,5 +35,6 @@
#define PCI_CLASS_RNG 0xff0000
#define PCI_CLASS_BLN 0xff0000
#define PCI_CLASS_9P 0xff0000
+#define PCI_CLASS_PSTORE 0xff0000
#endif /* VIRTIO_PCI_DEV_H_ */
diff --git a/include/kvm/virtio-pstore.h b/include/kvm/virtio-pstore.h
new file mode 100644
index 0000000..293ab57
--- /dev/null
+++ b/include/kvm/virtio-pstore.h
@@ -0,0 +1,31 @@
+#ifndef KVM__PSTORE_VIRTIO_H
+#define KVM__PSTORE_VIRTIO_H
+
+struct kvm;
+
+#define VIRTIO_PSTORE_TYPE_UNKNOWN 0
+#define VIRTIO_PSTORE_TYPE_DMESG 1
+
+#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_FL_COMPRESSED 1
+
+struct pstore_hdr {
+ u64 id;
+ u32 flags;
+ u16 cmd;
+ u16 type;
+ u64 time_sec;
+ u32 time_nsec;
+ u32 unused;
+};
+
+int virtio_pstore__init(struct kvm *kvm);
+int virtio_pstore__exit(struct kvm *kvm);
+
+#endif /* KVM__PSTORE_VIRTIO_H */
diff --git a/include/linux/virtio_ids.h b/include/linux/virtio_ids.h
index 5f60aa4..f34cabc 100644
--- a/include/linux/virtio_ids.h
+++ b/include/linux/virtio_ids.h
@@ -40,5 +40,6 @@
#define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */
#define VIRTIO_ID_CAIF 12 /* Virtio caif */
#define VIRTIO_ID_INPUT 18 /* virtio input */
+#define VIRTIO_ID_PSTORE 19 /* virtio pstore */
#endif /* _LINUX_VIRTIO_IDS_H */
diff --git a/virtio/pstore.c b/virtio/pstore.c
new file mode 100644
index 0000000..094e54b
--- /dev/null
+++ b/virtio/pstore.c
@@ -0,0 +1,359 @@
+#include "kvm/virtio-pstore.h"
+
+#include "kvm/virtio-pci-dev.h"
+
+#include "kvm/virtio.h"
+#include "kvm/util.h"
+#include "kvm/kvm.h"
+#include "kvm/threadpool.h"
+#include "kvm/guest_compat.h"
+
+#include <linux/virtio_ring.h>
+
+#include <linux/list.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <pthread.h>
+#include <linux/kernel.h>
+
+#define NUM_VIRT_QUEUES 1
+#define VIRTIO_PSTORE_QUEUE_SIZE 128
+
+struct pstore_dev_job {
+ struct virt_queue *vq;
+ struct pstore_dev *pdev;
+ struct thread_pool__job job_id;
+};
+
+struct pstore_dev {
+ struct list_head list;
+ struct virtio_device vdev;
+
+ int fd;
+ DIR *dir;
+
+ /* virtio queue */
+ struct virt_queue vqs[NUM_VIRT_QUEUES];
+ struct pstore_dev_job jobs[NUM_VIRT_QUEUES];
+};
+
+static LIST_HEAD(pdevs);
+static int compat_id = -1;
+
+static u8 *get_config(struct kvm *kvm, void *dev)
+{
+ /* Unused */
+ return 0;
+}
+
+static u32 get_host_features(struct kvm *kvm, void *dev)
+{
+ /* Unused */
+ return 0;
+}
+
+static void set_guest_features(struct kvm *kvm, void *dev, u32 features)
+{
+ /* Unused */
+}
+
+static void virtio_pstore_hdr_to_filename(struct kvm *kvm, struct pstore_hdr *hdr,
+ char *buf, size_t sz)
+{
+ const char *basename;
+
+ switch (hdr->type) {
+ case VIRTIO_PSTORE_TYPE_DMESG:
+ basename = "dmesg";
+ break;
+ default:
+ basename = "unknown";
+ break;
+ }
+
+ snprintf(buf, sz, "%s/%s-%llu%s", kvm->cfg.pstore_path, basename,
+ hdr->id, hdr->flags & VIRTIO_PSTORE_FL_COMPRESSED ? ".enc.z" : "");
+}
+
+static void virtio_pstore_filename_to_hdr(struct kvm *kvm, struct pstore_hdr *hdr,
+ char *name, char *buf, size_t sz)
+{
+ size_t len = strlen(name);
+
+ hdr->flags = 0;
+ if (!strncmp(name + len - 6, ".enc.z", 6))
+ hdr->flags |= VIRTIO_PSTORE_FL_COMPRESSED;
+
+ snprintf(buf, sz, "%s/%s", kvm->cfg.pstore_path, name);
+
+ if (!strncmp(name, "dmesg", 5)) {
+ hdr->type = VIRTIO_PSTORE_TYPE_DMESG;
+ name += 5;
+ } else if (!strncmp(name, "unknown", 7)) {
+ hdr->type = VIRTIO_PSTORE_TYPE_UNKNOWN;
+ name += 7;
+ }
+
+ hdr->id = strtoul(name + 1, NULL, 0);
+}
+
+static int virtio_pstore_do_open(struct kvm *kvm, struct pstore_dev *pdev,
+ struct pstore_hdr *hdr, struct iovec *iov)
+{
+ pdev->dir = opendir(kvm->cfg.pstore_path);
+ if (pdev->dir == NULL)
+ return -errno;
+
+ return 0;
+}
+
+static int virtio_pstore_do_close(struct kvm *kvm, struct pstore_dev *pdev,
+ struct pstore_hdr *hdr, struct iovec *iov)
+{
+ if (pdev->dir == NULL)
+ return -1;
+
+ closedir(pdev->dir);
+ pdev->dir = NULL;
+
+ return 0;
+}
+
+static ssize_t virtio_pstore_do_write(struct kvm *kvm, struct pstore_dev *pdev,
+ struct pstore_hdr *hdr, struct iovec *iov)
+{
+ char path[PATH_MAX];
+ FILE *fp;
+ ssize_t len = 0;
+
+ virtio_pstore_hdr_to_filename(kvm, hdr, path, sizeof(path));
+
+ fp = fopen(path, "a");
+ if (fp == NULL)
+ return -1;
+
+ len = fwrite(iov[1].iov_base, iov[1].iov_len, 1, fp);
+ if (len < 0 && errno == EAGAIN)
+ len = 0;
+
+ fclose(fp);
+ return len;
+}
+
+static ssize_t virtio_pstore_do_read(struct kvm *kvm, struct pstore_dev *pdev,
+ struct pstore_hdr *hdr, struct iovec *iov)
+{
+ char path[PATH_MAX];
+ FILE *fp;
+ ssize_t len = 0;
+ struct stat stbuf;
+ struct dirent *dent;
+
+ if (pdev->dir == NULL)
+ return 0;
+
+ dent = readdir(pdev->dir);
+ while (dent) {
+ if (dent->d_name[0] != '.')
+ break;
+ dent = readdir(pdev->dir);
+ }
+
+ if (dent == NULL)
+ return 0;
+
+ virtio_pstore_filename_to_hdr(kvm, hdr, dent->d_name, path, sizeof(path));
+ if (stat(path, &stbuf) < 0)
+ return -1;
+
+ fp = fopen(path, "r");
+ if (fp == NULL)
+ return -1;
+
+ len = fread(iov[1].iov_base, 1, iov[1].iov_len, fp);
+ if (len < 0 && errno == EAGAIN)
+ len = 0;
+
+ hdr->id = virtio_host_to_guest_u64(pdev->vqs, hdr->id);
+ hdr->flags = virtio_host_to_guest_u32(pdev->vqs, hdr->flags);
+
+ hdr->time_sec = virtio_host_to_guest_u64(pdev->vqs, stbuf.st_ctim.tv_sec);
+ hdr->time_nsec = virtio_host_to_guest_u32(pdev->vqs, stbuf.st_ctim.tv_nsec);
+
+ fclose(fp);
+ return len;
+}
+
+static ssize_t virtio_pstore_do_erase(struct kvm *kvm, struct pstore_dev *pdev,
+ struct pstore_hdr *hdr, struct iovec *iov)
+{
+ char path[PATH_MAX];
+
+ virtio_pstore_hdr_to_filename(kvm, hdr, path, sizeof(path));
+
+ return unlink(path);
+}
+
+static bool virtio_pstore_do_io_request(struct kvm *kvm, struct pstore_dev *pdev,
+ struct virt_queue *vq)
+{
+ struct iovec iov[VIRTIO_PSTORE_QUEUE_SIZE];
+ struct pstore_hdr *hdr;
+ ssize_t len = 0;
+ u16 out, in, head;
+
+ head = virt_queue__get_iov(vq, iov, &out, &in, kvm);
+
+ hdr = iov[0].iov_base;
+
+ switch (virtio_guest_to_host_u16(vq, hdr->cmd)) {
+ case VIRTIO_PSTORE_CMD_OPEN:
+ len = virtio_pstore_do_open(kvm, pdev, hdr, iov);
+ break;
+ case VIRTIO_PSTORE_CMD_READ:
+ len = virtio_pstore_do_read(kvm, pdev, hdr, iov);
+ break;
+ case VIRTIO_PSTORE_CMD_WRITE:
+ len = virtio_pstore_do_write(kvm, pdev, hdr, iov);
+ break;
+ case VIRTIO_PSTORE_CMD_CLOSE:
+ virtio_pstore_do_close(kvm, pdev, hdr, iov);
+ break;
+ case VIRTIO_PSTORE_CMD_ERASE:
+ len = virtio_pstore_do_erase(kvm, pdev, hdr, iov);
+ break;
+ default:
+ return false;
+ }
+
+ if (len < 0)
+ return false;
+
+ virt_queue__set_used_elem(vq, head, len);
+
+ return true;
+}
+
+static void virtio_pstore_do_io(struct kvm *kvm, void *param)
+{
+ struct pstore_dev_job *job = param;
+ struct virt_queue *vq = job->vq;
+ struct pstore_dev *pdev = job->pdev;
+
+ while (virt_queue__available(vq))
+ virtio_pstore_do_io_request(kvm, pdev, vq);
+
+ pdev->vdev.ops->signal_vq(kvm, &pdev->vdev, vq - pdev->vqs);
+}
+
+static int init_vq(struct kvm *kvm, void *dev, u32 vq, u32 page_size, u32 align,
+ u32 pfn)
+{
+ struct pstore_dev *pdev = dev;
+ struct virt_queue *queue;
+ struct pstore_dev_job *job;
+ void *p;
+
+ compat__remove_message(compat_id);
+
+ queue = &pdev->vqs[vq];
+ queue->pfn = pfn;
+ p = virtio_get_vq(kvm, queue->pfn, page_size);
+
+ job = &pdev->jobs[vq];
+
+ vring_init(&queue->vring, VIRTIO_PSTORE_QUEUE_SIZE, p, align);
+
+ *job = (struct pstore_dev_job) {
+ .vq = queue,
+ .pdev = pdev,
+ };
+
+ thread_pool__init_job(&job->job_id, kvm, virtio_pstore_do_io, job);
+
+ return 0;
+}
+
+static int notify_vq(struct kvm *kvm, void *dev, u32 vq)
+{
+ struct pstore_dev *pdev = dev;
+
+ thread_pool__do_job(&pdev->jobs[vq].job_id);
+
+ return 0;
+}
+
+static int get_pfn_vq(struct kvm *kvm, void *dev, u32 vq)
+{
+ struct pstore_dev *pdev = dev;
+
+ return pdev->vqs[vq].pfn;
+}
+
+static int get_size_vq(struct kvm *kvm, void *dev, u32 vq)
+{
+ return VIRTIO_PSTORE_QUEUE_SIZE;
+}
+
+static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
+{
+ /* FIXME: dynamic */
+ return size;
+}
+
+static struct virtio_ops pstore_dev_virtio_ops = {
+ .get_config = get_config,
+ .get_host_features = get_host_features,
+ .set_guest_features = set_guest_features,
+ .init_vq = init_vq,
+ .notify_vq = notify_vq,
+ .get_pfn_vq = get_pfn_vq,
+ .get_size_vq = get_size_vq,
+ .set_size_vq = set_size_vq,
+};
+
+int virtio_pstore__init(struct kvm *kvm)
+{
+ struct pstore_dev *pdev;
+ int r;
+
+ if (!kvm->cfg.pstore_path)
+ return 0;
+
+ pdev = malloc(sizeof(*pdev));
+ if (pdev == NULL)
+ return -ENOMEM;
+
+ r = virtio_init(kvm, pdev, &pdev->vdev, &pstore_dev_virtio_ops,
+ VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_PSTORE,
+ VIRTIO_ID_PSTORE, PCI_CLASS_PSTORE);
+ if (r < 0)
+ goto cleanup;
+
+ list_add_tail(&pdev->list, &pdevs);
+
+ if (compat_id == -1)
+ compat_id = virtio_compat_add_message("virtio-pstore", "CONFIG_VIRTIO_PSTORE");
+ return 0;
+cleanup:
+ free(pdev);
+
+ return r;
+}
+virtio_dev_init(virtio_pstore__init);
+
+int virtio_pstore__exit(struct kvm *kvm)
+{
+ struct pstore_dev *pdev, *tmp;
+
+ list_for_each_entry_safe(pdev, tmp, &pdevs, list) {
+ list_del(&pdev->list);
+ pdev->vdev.ops->exit(kvm, &pdev->vdev);
+ free(pdev);
+ }
+
+ return 0;
+}
+virtio_dev_exit(virtio_pstore__exit);
--
2.8.0