On Thu, 23 Jan 2020 13:47:50 +0000
Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote:
Hi,
> Don't ignore an error in the bus specific initialization function in
> virtio_init; don't ignore the result of virtio_init; and don't return 0
> in virtio_blk__init and virtio_scsi__init when we encounter an error.
> Hopefully this will save some developer's time debugging faulty virtio
> devices in a guest.
Seems like the right thing to do, but I was wondering how you triggered this? AFAICS virtio_init only fails when calloc() fails or you pass an illegal transport, with the latter looking like being hard coded to one of the two supported.
One minor thing below ...
>
> To take advantage of the cleanup function virtio_blk__exit, we have
> moved appending the new device to the list before the call to
> virtio_init.
>
> To safeguard against this in the future, virtio_init has been annoted
> with the compiler attribute warn_unused_result.
>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
> ---
> include/kvm/kvm.h | 1 +
> include/kvm/virtio.h | 7 ++++---
> include/linux/compiler.h | 2 +-
> virtio/9p.c | 9 ++++++---
> virtio/balloon.c | 10 +++++++---
> virtio/blk.c | 14 +++++++++-----
> virtio/console.c | 11 ++++++++---
> virtio/core.c | 9 +++++----
> virtio/net.c | 32 ++++++++++++++++++--------------
> virtio/scsi.c | 14 +++++++++-----
> 10 files changed, 68 insertions(+), 41 deletions(-)
>
> diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
> index 7a738183d67a..c6dc6ef72d11 100644
> --- a/include/kvm/kvm.h
> +++ b/include/kvm/kvm.h
> @@ -8,6 +8,7 @@
>
> #include <stdbool.h>
> #include <linux/types.h>
> +#include <linux/compiler.h>
> #include <time.h>
> #include <signal.h>
> #include <sys/prctl.h>
> diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h
> index 19b913732cd5..3a311f54f2a5 100644
> --- a/include/kvm/virtio.h
> +++ b/include/kvm/virtio.h
> @@ -7,6 +7,7 @@
> #include <linux/virtio_pci.h>
>
> #include <linux/types.h>
> +#include <linux/compiler.h>
> #include <linux/virtio_config.h>
> #include <sys/uio.h>
>
> @@ -204,9 +205,9 @@ struct virtio_ops {
> int (*reset)(struct kvm *kvm, struct virtio_device *vdev);
> };
>
> -int virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> - struct virtio_ops *ops, enum virtio_trans trans,
> - int device_id, int subsys_id, int class);
> +int __must_check virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> + struct virtio_ops *ops, enum virtio_trans trans,
> + int device_id, int subsys_id, int class);
> int virtio_compat_add_message(const char *device, const char *config);
> const char* virtio_trans_name(enum virtio_trans trans);
>
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index 898420b81aec..a662ba0a5c68 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -14,7 +14,7 @@
> #define __packed __attribute__((packed))
> #define __iomem
> #define __force
> -#define __must_check
> +#define __must_check __attribute__((warn_unused_result))
> #define unlikely
>
> #endif
> diff --git a/virtio/9p.c b/virtio/9p.c
> index ac70dbc31207..b78f2b3f0e09 100644
> --- a/virtio/9p.c
> +++ b/virtio/9p.c
> @@ -1551,11 +1551,14 @@ int virtio_9p_img_name_parser(const struct option *opt, const char *arg, int uns
> int virtio_9p__init(struct kvm *kvm)
> {
> struct p9_dev *p9dev;
> + int r;
>
> list_for_each_entry(p9dev, &devs, list) {
> - virtio_init(kvm, p9dev, &p9dev->vdev, &p9_dev_virtio_ops,
> - VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_9P,
> - VIRTIO_ID_9P, PCI_CLASS_9P);
> + r = virtio_init(kvm, p9dev, &p9dev->vdev, &p9_dev_virtio_ops,
> + VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_9P,
> + VIRTIO_ID_9P, PCI_CLASS_9P);
> + if (r < 0)
> + return r;
> }
>
> return 0;
> diff --git a/virtio/balloon.c b/virtio/balloon.c
> index 0bd16703dfee..8e8803fed607 100644
> --- a/virtio/balloon.c
> +++ b/virtio/balloon.c
> @@ -264,6 +264,8 @@ struct virtio_ops bln_dev_virtio_ops = {
>
> int virtio_bln__init(struct kvm *kvm)
> {
> + int r;
> +
> if (!kvm->cfg.balloon)
> return 0;
>
> @@ -273,9 +275,11 @@ int virtio_bln__init(struct kvm *kvm)
> bdev.stat_waitfd = eventfd(0, 0);
> memset(&bdev.config, 0, sizeof(struct virtio_balloon_config));
>
> - virtio_init(kvm, &bdev, &bdev.vdev, &bln_dev_virtio_ops,
> - VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_BLN,
> - VIRTIO_ID_BALLOON, PCI_CLASS_BLN);
> + r = virtio_init(kvm, &bdev, &bdev.vdev, &bln_dev_virtio_ops,
> + VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_BLN,
> + VIRTIO_ID_BALLOON, PCI_CLASS_BLN);
> + if (r < 0)
> + return r;
>
> if (compat_id == -1)
> compat_id = virtio_compat_add_message("virtio-balloon", "CONFIG_VIRTIO_BALLOON");
> diff --git a/virtio/blk.c b/virtio/blk.c
> index f267be1563dc..4d02d101af81 100644
> --- a/virtio/blk.c
> +++ b/virtio/blk.c
> @@ -306,6 +306,7 @@ static struct virtio_ops blk_dev_virtio_ops = {
> static int virtio_blk__init_one(struct kvm *kvm, struct disk_image *disk)
> {
> struct blk_dev *bdev;
> + int r;
>
> if (!disk)
> return -EINVAL;
> @@ -323,12 +324,14 @@ static int virtio_blk__init_one(struct kvm *kvm, struct disk_image *disk)
> .kvm = kvm,
> };
>
> - virtio_init(kvm, bdev, &bdev->vdev, &blk_dev_virtio_ops,
> - VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_BLK,
> - VIRTIO_ID_BLOCK, PCI_CLASS_BLK);
> -
> list_add_tail(&bdev->list, &bdevs);
>
> + r = virtio_init(kvm, bdev, &bdev->vdev, &blk_dev_virtio_ops,
> + VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_BLK,
> + VIRTIO_ID_BLOCK, PCI_CLASS_BLK);
> + if (r < 0)
> + return r;
> +
> disk_image__set_callback(bdev->disk, virtio_blk_complete);
>
> if (compat_id == -1)
> @@ -359,7 +362,8 @@ int virtio_blk__init(struct kvm *kvm)
>
> return 0;
> cleanup:
> - return virtio_blk__exit(kvm);
> + virtio_blk__exit(kvm);
> + return r;
> }
> virtio_dev_init(virtio_blk__init);
>
> diff --git a/virtio/console.c b/virtio/console.c
> index f1be02549222..e0b98df37965 100644
> --- a/virtio/console.c
> +++ b/virtio/console.c
> @@ -230,12 +230,17 @@ static struct virtio_ops con_dev_virtio_ops = {
>
> int virtio_console__init(struct kvm *kvm)
> {
> + int r;
> +
> if (kvm->cfg.active_console != CONSOLE_VIRTIO)
> return 0;
>
> - virtio_init(kvm, &cdev, &cdev.vdev, &con_dev_virtio_ops,
> - VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_CONSOLE,
> - VIRTIO_ID_CONSOLE, PCI_CLASS_CONSOLE);
> + r = virtio_init(kvm, &cdev, &cdev.vdev, &con_dev_virtio_ops,
> + VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_CONSOLE,
> + VIRTIO_ID_CONSOLE, PCI_CLASS_CONSOLE);
> + if (r < 0)
> + return r;
> +
> if (compat_id == -1)
> compat_id = virtio_compat_add_message("virtio-console", "CONFIG_VIRTIO_CONSOLE");
>
> diff --git a/virtio/core.c b/virtio/core.c
> index e10ec362e1ea..f5b3c07fc100 100644
> --- a/virtio/core.c
> +++ b/virtio/core.c
> @@ -259,6 +259,7 @@ int virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> int device_id, int subsys_id, int class)
> {
> void *virtio;
> + int r;
>
> switch (trans) {
> case VIRTIO_PCI:
> @@ -272,7 +273,7 @@ int virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> vdev->ops->init = virtio_pci__init;
> vdev->ops->exit = virtio_pci__exit;
> vdev->ops->reset = virtio_pci__reset;
> - vdev->ops->init(kvm, dev, vdev, device_id, subsys_id, class);
> + r = vdev->ops->init(kvm, dev, vdev, device_id, subsys_id, class);
> break;
> case VIRTIO_MMIO:
> virtio = calloc(sizeof(struct virtio_mmio), 1);
> @@ -285,13 +286,13 @@ int virtio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> vdev->ops->init = virtio_mmio_init;
> vdev->ops->exit = virtio_mmio_exit;
> vdev->ops->reset = virtio_mmio_reset;
> - vdev->ops->init(kvm, dev, vdev, device_id, subsys_id, class);
> + r = vdev->ops->init(kvm, dev, vdev, device_id, subsys_id, class);
> break;
> default:
> - return -1;
> + r = -1;
> };
>
> - return 0;
> + return r;
> }
>
> int virtio_compat_add_message(const char *device, const char *config)
> diff --git a/virtio/net.c b/virtio/net.c
> index 091406912a24..425c13ba1136 100644
> --- a/virtio/net.c
> +++ b/virtio/net.c
> @@ -910,7 +910,7 @@ done:
>
> static int virtio_net__init_one(struct virtio_net_params *params)
> {
> - int i, err;
> + int i, r;
> struct net_dev *ndev;
> struct virtio_ops *ops;
> enum virtio_trans trans = VIRTIO_DEFAULT_TRANS(params->kvm);
> @@ -920,10 +920,8 @@ static int virtio_net__init_one(struct virtio_net_params *params)
> return -ENOMEM;
>
> ops = malloc(sizeof(*ops));
> - if (ops == NULL) {
> - err = -ENOMEM;
> - goto err_free_ndev;
> - }
> + if (ops == NULL)
> + return -ENOMEM;
Doesn't that leave struct net_dev allocated? I am happy with removing the goto, but we should free(ndev) before we return, I think.
Cheers,
Andre.
>
> list_add_tail(&ndev->list, &ndevs);
>
> @@ -969,8 +967,10 @@ static int virtio_net__init_one(struct virtio_net_params *params)
> virtio_trans_name(trans));
> }
>
> - virtio_init(params->kvm, ndev, &ndev->vdev, ops, trans,
> - PCI_DEVICE_ID_VIRTIO_NET, VIRTIO_ID_NET, PCI_CLASS_NET);
> + r = virtio_init(params->kvm, ndev, &ndev->vdev, ops, trans,
> + PCI_DEVICE_ID_VIRTIO_NET, VIRTIO_ID_NET, PCI_CLASS_NET);
> + if (r < 0)
> + return r;
>
> if (params->vhost)
> virtio_net__vhost_init(params->kvm, ndev);
> @@ -979,19 +979,17 @@ static int virtio_net__init_one(struct virtio_net_params *params)
> compat_id = virtio_compat_add_message("virtio-net", "CONFIG_VIRTIO_NET");
>
> return 0;
> -
> -err_free_ndev:
> - free(ndev);
> - return err;
> }
>
> int virtio_net__init(struct kvm *kvm)
> {
> - int i;
> + int i, r;
>
> for (i = 0; i < kvm->cfg.num_net_devices; i++) {
> kvm->cfg.net_params[i].kvm = kvm;
> - virtio_net__init_one(&kvm->cfg.net_params[i]);
> + r = virtio_net__init_one(&kvm->cfg.net_params[i]);
> + if (r < 0)
> + goto cleanup;
> }
>
> if (kvm->cfg.num_net_devices == 0 && kvm->cfg.no_net == 0) {
> @@ -1007,10 +1005,16 @@ int virtio_net__init(struct kvm *kvm)
> str_to_mac(kvm->cfg.guest_mac, net_params.guest_mac);
> str_to_mac(kvm->cfg.host_mac, net_params.host_mac);
>
> - virtio_net__init_one(&net_params);
> + r = virtio_net__init_one(&net_params);
> + if (r < 0)
> + goto cleanup;
> }
>
> return 0;
> +
> +cleanup:
> + virtio_net__exit(kvm);
> + return r;
> }
> virtio_dev_init(virtio_net__init);
>
> diff --git a/virtio/scsi.c b/virtio/scsi.c
> index 1ec78fe0945a..16a86cb7e0e6 100644
> --- a/virtio/scsi.c
> +++ b/virtio/scsi.c
> @@ -234,6 +234,7 @@ static void virtio_scsi_vhost_init(struct kvm *kvm, struct scsi_dev *sdev)
> static int virtio_scsi_init_one(struct kvm *kvm, struct disk_image *disk)
> {
> struct scsi_dev *sdev;
> + int r;
>
> if (!disk)
> return -EINVAL;
> @@ -260,12 +261,14 @@ static int virtio_scsi_init_one(struct kvm *kvm, struct disk_image *disk)
> strlcpy((char *)&sdev->target.vhost_wwpn, disk->wwpn, sizeof(sdev->target.vhost_wwpn));
> sdev->target.vhost_tpgt = strtol(disk->tpgt, NULL, 0);
>
> - virtio_init(kvm, sdev, &sdev->vdev, &scsi_dev_virtio_ops,
> - VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_SCSI,
> - VIRTIO_ID_SCSI, PCI_CLASS_BLK);
> -
> list_add_tail(&sdev->list, &sdevs);
>
> + r = virtio_init(kvm, sdev, &sdev->vdev, &scsi_dev_virtio_ops,
> + VIRTIO_DEFAULT_TRANS(kvm), PCI_DEVICE_ID_VIRTIO_SCSI,
> + VIRTIO_ID_SCSI, PCI_CLASS_BLK);
> + if (r < 0)
> + return r;
> +
> virtio_scsi_vhost_init(kvm, sdev);
>
> if (compat_id == -1)
> @@ -302,7 +305,8 @@ int virtio_scsi_init(struct kvm *kvm)
>
> return 0;
> cleanup:
> - return virtio_scsi_exit(kvm);
> + virtio_scsi_exit(kvm);
> + return r;
> }
> virtio_dev_init(virtio_scsi_init);
>
