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virtio-pci library: introduce vp_modern_get_driver_features() 

This patch introduce a helper to get driver/guest features from the
device.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210602021536.39525-3-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
This commit is contained in:
Jason Wang 2021-06-02 10:15:34 +08:00 committed by Michael S. Tsirkin
parent 530a5678bc
commit 0140b3d076
2 changed files with 22 additions and 0 deletions
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21
drivers/virtio/virtio_pci_modern_dev.c
View File

@ -383,6 +383,27 @@ u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
}
EXPORT_SYMBOL_GPL(vp_modern_get_features);
/*
* vp_modern_get_driver_features - get driver features from device
* @mdev: the modern virtio-pci device
*
* Returns the driver features read from the device
*/
u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev)
{
struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
u64 features;
vp_iowrite32(0, &cfg->guest_feature_select);
features = vp_ioread32(&cfg->guest_feature);
vp_iowrite32(1, &cfg->guest_feature_select);
features |= ((u64)vp_ioread32(&cfg->guest_feature) << 32);
return features;
}
EXPORT_SYMBOL_GPL(vp_modern_get_driver_features);
/*
* vp_modern_set_features - set features to device
* @mdev: the modern virtio-pci device

1
include/linux/virtio_pci_modern.h
View File

@ -79,6 +79,7 @@ static inline void vp_iowrite64_twopart(u64 val,
}
u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev);
u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev);
void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
u64 features);
u32 vp_modern_generation(struct virtio_pci_modern_device *mdev);