[PATCH 2/4] virtio-pci library: introduce vp_modern_get_driver_features()
From: Jason Wang <hidden>
Date: 2021-06-01 08:45:40
Also in:
kvm, lkml, virtualization
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
This patch introduce a helper to get driver/guest features from the device. Signed-off-by: Jason Wang <redacted> --- drivers/virtio/virtio_pci_modern_dev.c | 21 +++++++++++++++++++++ include/linux/virtio_pci_modern.h | 1 + 2 files changed, 22 insertions(+)
diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index 54f297028586..e11ed748e661 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c@@ -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
diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
index 6a95b58fd0f4..eb2bd9b4077d 100644
--- a/include/linux/virtio_pci_modern.h
+++ b/include/linux/virtio_pci_modern.h@@ -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);
--
2.25.1