Hi Akihiko I hit qemu core dump when I tested this series of patches with virtio-net regression tests, and based on the test result this bug can be reproduced by just booting a guest. For the details of core dump info please review the attachment.
Regards
Lei
On Sat, Jan 4, 2025 at 3:37 PM Akihiko Odaki <akihiko.od...@daynix.com> wrote:
>
> Some features are not always available with vhost. Legacy features are
> not available with vp_vdpa in particular. virtio devices used to disable
> them when not available even if the corresponding properties were
> explicitly set to "on".
>
> QEMU already has OnOffAuto type, which includes the "auto" value to let
> it automatically decide the effective value. Convert feature properties
> to OnOffAuto and set them "auto" by default to utilize it. This allows
> QEMU to report an error if they are set "on" and the corresponding
> features are not available.
>
> Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com>
> ---
> include/hw/virtio/virtio.h | 38 +++++++++++++++++++++-----------------
> hw/core/machine.c | 4 +++-
> hw/virtio/virtio-bus.c | 14 ++++++++++++--
> hw/virtio/virtio.c | 4 +++-
> 4 files changed, 39 insertions(+), 21 deletions(-)
>
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 638691028050..b854c2cb1d04 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -113,7 +113,8 @@ struct VirtIODevice
> uint16_t queue_sel;
> /**
> * These fields represent a set of VirtIO features at various
> - * levels of the stack. @host_features indicates the complete
> + * levels of the stack. @requested_features indicates the feature
> + * set the user requested. @host_features indicates the complete
> * feature set the VirtIO device can offer to the driver.
> * @guest_features indicates which features the VirtIO driver has
> * selected by writing to the feature register. Finally
> @@ -121,6 +122,7 @@ struct VirtIODevice
> * backend (e.g. vhost) and could potentially be a subset of the
> * total feature set offered by QEMU.
> */
> + OnOffAutoBit64 requested_features;
> uint64_t host_features;
> uint64_t guest_features;
> uint64_t backend_features;
> @@ -149,6 +151,7 @@ struct VirtIODevice
> bool started;
> bool start_on_kick; /* when virtio 1.0 feature has not been negotiated */
> bool disable_legacy_check;
> + bool force_features_auto;
> bool vhost_started;
> VMChangeStateEntry *vmstate;
> char *bus_name;
> @@ -376,22 +379,23 @@ typedef struct VirtIOSCSIConf VirtIOSCSIConf;
> typedef struct VirtIORNGConf VirtIORNGConf;
>
> #define DEFINE_VIRTIO_COMMON_FEATURES(_state, _field) \
> - DEFINE_PROP_BIT64("indirect_desc", _state, _field, \
> - VIRTIO_RING_F_INDIRECT_DESC, true), \
> - DEFINE_PROP_BIT64("event_idx", _state, _field, \
> - VIRTIO_RING_F_EVENT_IDX, true), \
> - DEFINE_PROP_BIT64("notify_on_empty", _state, _field, \
> - VIRTIO_F_NOTIFY_ON_EMPTY, true), \
> - DEFINE_PROP_BIT64("any_layout", _state, _field, \
> - VIRTIO_F_ANY_LAYOUT, true), \
> - DEFINE_PROP_BIT64("iommu_platform", _state, _field, \
> - VIRTIO_F_IOMMU_PLATFORM, false), \
> - DEFINE_PROP_BIT64("packed", _state, _field, \
> - VIRTIO_F_RING_PACKED, false), \
> - DEFINE_PROP_BIT64("queue_reset", _state, _field, \
> - VIRTIO_F_RING_RESET, true), \
> - DEFINE_PROP_BIT64("in_order", _state, _field, \
> - VIRTIO_F_IN_ORDER, false)
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("indirect_desc", _state, _field, \
> + VIRTIO_RING_F_INDIRECT_DESC, \
> + ON_OFF_AUTO_AUTO), \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("event_idx", _state, _field, \
> + VIRTIO_RING_F_EVENT_IDX,
> ON_OFF_AUTO_AUTO), \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("notify_on_empty", _state, _field, \
> + VIRTIO_F_NOTIFY_ON_EMPTY,
> ON_OFF_AUTO_AUTO), \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("any_layout", _state, _field, \
> + VIRTIO_F_ANY_LAYOUT, ON_OFF_AUTO_AUTO), \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("iommu_platform", _state, _field, \
> + VIRTIO_F_IOMMU_PLATFORM, ON_OFF_AUTO_OFF),
> \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("packed", _state, _field, \
> + VIRTIO_F_RING_PACKED, ON_OFF_AUTO_OFF), \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("queue_reset", _state, _field, \
> + VIRTIO_F_RING_RESET, ON_OFF_AUTO_AUTO), \
> + DEFINE_PROP_ON_OFF_AUTO_BIT64("in_order", _state, _field, \
> + VIRTIO_F_IN_ORDER, ON_OFF_AUTO_OFF)
>
> hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n);
> bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n);
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index c949af97668d..bff26b95dd74 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -36,7 +36,9 @@
> #include "hw/virtio/virtio-iommu.h"
> #include "audio/audio.h"
>
> -GlobalProperty hw_compat_9_2[] = {};
> +GlobalProperty hw_compat_9_2[] = {
> + { TYPE_VIRTIO_DEVICE, "x-force-features-auto", "on" },
> +};
> const size_t hw_compat_9_2_len = G_N_ELEMENTS(hw_compat_9_2);
>
> GlobalProperty hw_compat_9_1[] = {
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index 896feb37a1ca..75d433b252d5 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -50,6 +50,7 @@ void virtio_bus_device_plugged(VirtIODevice *vdev, Error
> **errp)
> bool has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
> bool vdev_has_iommu;
> Error *local_err = NULL;
> + uint64_t features;
>
> DPRINTF("%s: plug device.\n", qbus->name);
>
> @@ -63,13 +64,22 @@ void virtio_bus_device_plugged(VirtIODevice *vdev, Error
> **errp)
>
> /* Get the features of the plugged device. */
> assert(vdc->get_features != NULL);
> - vdev->host_features = vdc->get_features(vdev, vdev->host_features,
> - &local_err);
> + features = vdev->host_features | vdev->requested_features.auto_bits |
> + vdev->requested_features.on_bits;
> + features = vdc->get_features(vdev, features, &local_err);
> if (local_err) {
> error_propagate(errp, local_err);
> return;
> }
>
> + if (!vdev->force_features_auto &&
> + (features & vdev->requested_features.on_bits) !=
> vdev->requested_features.on_bits) {
> + error_setg(errp, "A requested feature is not supported by the
> device");
> + return;
> + }
> +
> + vdev->host_features = features;
> +
> if (klass->device_plugged != NULL) {
> klass->device_plugged(qbus->parent, &local_err);
> }
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 85110bce3744..83f803fc703d 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -4013,11 +4013,13 @@ static void virtio_device_instance_finalize(Object
> *obj)
> }
>
> static const Property virtio_properties[] = {
> - DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
> + DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, requested_features),
> DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true),
> DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag,
> true),
> DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice,
> disable_legacy_check, false),
> + DEFINE_PROP_BOOL("x-force-features-auto", VirtIODevice,
> + force_features_auto, false),
> };
>
> static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
>
> --
> 2.47.1
>
>
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