On Fri, Sep 22, 2023 at 09:49:18AM +0800, Xuan Zhuo wrote: > On Thu, 21 Sep 2023 10:02:53 -0400, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > On Mon, Aug 01, 2022 at 02:38:50PM +0800, Xuan Zhuo wrote: > > > Introduce new helpers to implement queue reset and get queue reset > > > status. > > > > > > https://github.com/oasis-tcs/virtio-spec/issues/124 > > > https://github.com/oasis-tcs/virtio-spec/issues/139 > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> > > > Acked-by: Jason Wang <jasowang@xxxxxxxxxx> > > > --- > > > drivers/virtio/virtio_pci_modern_dev.c | 39 ++++++++++++++++++++++++++ > > > include/linux/virtio_pci_modern.h | 2 ++ > > > 2 files changed, 41 insertions(+) > > > > > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > > > index fa2a9445bb18..869cb46bef96 100644 > > > --- a/drivers/virtio/virtio_pci_modern_dev.c > > > +++ b/drivers/virtio/virtio_pci_modern_dev.c > > > @@ -3,6 +3,7 @@ > > > #include <linux/virtio_pci_modern.h> > > > #include <linux/module.h> > > > #include <linux/pci.h> > > > +#include <linux/delay.h> > > > > > > /* > > > * vp_modern_map_capability - map a part of virtio pci capability > > > @@ -474,6 +475,44 @@ void vp_modern_set_status(struct virtio_pci_modern_device *mdev, > > > } > > > EXPORT_SYMBOL_GPL(vp_modern_set_status); > > > > > > +/* > > > + * vp_modern_get_queue_reset - get the queue reset status > > > + * @mdev: the modern virtio-pci device > > > + * @index: queue index > > > + */ > > > +int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index) > > > +{ > > > + struct virtio_pci_modern_common_cfg __iomem *cfg; > > > + > > > + cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common; > > > + > > > + vp_iowrite16(index, &cfg->cfg.queue_select); > > > + return vp_ioread16(&cfg->queue_reset); > > > +} > > > +EXPORT_SYMBOL_GPL(vp_modern_get_queue_reset); > > > + > > > > Actually, this does not validate that the config structure is big > > enough. So it can access some unrelated memory. Don't know whether > > that's exploitable e.g. for CoCo but not nice, anyway. > > Need to validate the size and disable reset if it's too small. > > > static int vp_modern_disable_vq_and_reset(struct virtqueue *vq) > { > struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev); > struct virtio_pci_modern_device *mdev = &vp_dev->mdev; > struct virtio_pci_vq_info *info; > unsigned long flags; > > -> if (!virtio_has_feature(vq->vdev, VIRTIO_F_RING_RESET)) > return -ENOENT; > > vp_modern_set_queue_reset(mdev, vq->index); > > > I checked VIRTIO_F_RING_RESET before call this. Yes but the point is that virtio is used with untrusted devices (e.g. for SEV/TDX), so you can't really assume config structures are in sync with feature bits. > Do you mean, we should put the check to this function. > > > Thanks. > > > > > > > > > > +/* > > > + * vp_modern_set_queue_reset - reset the queue > > > + * @mdev: the modern virtio-pci device > > > + * @index: queue index > > > + */ > > > +void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index) > > > +{ > > > + struct virtio_pci_modern_common_cfg __iomem *cfg; > > > + > > > + cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common; > > > + > > > + vp_iowrite16(index, &cfg->cfg.queue_select); > > > + vp_iowrite16(1, &cfg->queue_reset); > > > + > > > + while (vp_ioread16(&cfg->queue_reset)) > > > + msleep(1); > > > + > > > + while (vp_ioread16(&cfg->cfg.queue_enable)) > > > + msleep(1); > > > +} > > > +EXPORT_SYMBOL_GPL(vp_modern_set_queue_reset); > > > + > > > /* > > > * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue > > > * @mdev: the modern virtio-pci device > > > diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h > > > index 05123b9a606f..c4eeb79b0139 100644 > > > --- a/include/linux/virtio_pci_modern.h > > > +++ b/include/linux/virtio_pci_modern.h > > > @@ -113,4 +113,6 @@ void __iomem * vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev, > > > u16 index, resource_size_t *pa); > > > int vp_modern_probe(struct virtio_pci_modern_device *mdev); > > > void vp_modern_remove(struct virtio_pci_modern_device *mdev); > > > +int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index); > > > +void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index); > > > #endif > > > -- > > > 2.31.0 > >
