This patch introduce a helper to get driver/guest features from the
device.
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
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
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