[PATCH RFC v6 12/20] virtio: disallow late feature changes for virtio-1
From: Cornelia Huck <hidden>
Date: 2014-12-11 13:25:57
Also in:
qemu-devel
Subsystem:
the rest · Maintainer:
Linus Torvalds
For virtio-1 devices, the driver must not attempt to set feature bits after it set FEATURES_OK in the device status. Simply reject it in that case. Signed-off-by: Cornelia Huck <redacted> --- hw/virtio/virtio.c | 16 ++++++++++++++-- include/hw/virtio/virtio.h | 2 ++ 2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 57190ba..a3dd67b 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c@@ -978,7 +978,7 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f) vmstate_save_state(f, &vmstate_virtio, vdev); } -int virtio_set_features(VirtIODevice *vdev, uint64_t val) +static int __virtio_set_features(VirtIODevice *vdev, uint64_t val) { BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); VirtioBusClass *vbusk = VIRTIO_BUS_GET_CLASS(qbus);
@@ -994,6 +994,18 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val) return bad ? -1 : 0; } +int virtio_set_features(VirtIODevice *vdev, uint64_t val) +{ + /* + * The driver must not attempt to set features after feature negotiation + * has finished. + */ + if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) { + return -EINVAL; + } + return __virtio_set_features(vdev, val); +} + int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) { int i, ret;
@@ -1026,7 +1038,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) qemu_get_be32s(f, &features); /* XXX features >= 32 */ - if (virtio_set_features(vdev, features) < 0) { + if (__virtio_set_features(vdev, features) < 0) { supported_features = k->get_features(qbus->parent); error_report("Features 0x%x unsupported. Allowed features: 0x%lx", features, supported_features);
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index b63ced3..a24e403 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h@@ -32,6 +32,8 @@ #define VIRTIO_CONFIG_S_DRIVER 2 /* Driver has used its parts of the config, and is happy */ #define VIRTIO_CONFIG_S_DRIVER_OK 4 +/* Driver has finished configuring features */ +#define VIRTIO_CONFIG_S_FEATURES_OK 8 /* We've given up on this device. */ #define VIRTIO_CONFIG_S_FAILED 0x80
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1.7.9.5