From 0140b3d07617e71a8d9509776434ced107572fc8 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 2 Jun 2021 10:15:34 +0800 Subject: 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 Link: https://lore.kernel.org/r/20210602021536.39525-3-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin Reviewed-by: Eli Cohen --- drivers/virtio/virtio_pci_modern_dev.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'drivers/virtio') 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 -- cgit v1.2.3