virtio_pci_modern: allow configuring extended features

The virtio specifications allows for up to 128 bits for the
device features. Soon we are going to use some of the 'extended'
bits features (above 64) for the virtio_net driver.

Extend the virtio pci modern driver to support configuring the full
virtio features range, replacing the unrolled loops reading and
writing the features space with explicit one bounded to the actual
features space size in word and implementing the get_extended_features
callback.

Note that in vp_finalize_features() we only need to cache the lower
64 features bits, to process the transport features.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 7182f43ed055150a732d0461370c76ee91f867c7..dd0e65f71d4131e59db38dc1ec7a8b8670560fcf 100644 (file)
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -22,11 +22,11 @@
 
 #define VIRTIO_AVQ_SGS_MAX     4
 
-static u64 vp_get_features(struct virtio_device *vdev)
+static void vp_get_features(struct virtio_device *vdev, u64 *features)
 {
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 
-       return vp_modern_get_features(&vp_dev->mdev);
+       vp_modern_get_extended_features(&vp_dev->mdev, features);
 }
 
 static int vp_avq_index(struct virtio_device *vdev, u16 *index, u16 *num)
@@ -437,7 +437,7 @@ static int vp_finalize_features(struct virtio_device *vdev)
        if (vp_check_common_size(vdev))
                return -EINVAL;
 
-       vp_modern_set_features(&vp_dev->mdev, vdev->features);
+       vp_modern_set_extended_features(&vp_dev->mdev, vdev->features_array);
 
        return 0;
 }
@@ -1234,7 +1234,7 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
        .find_vqs       = vp_modern_find_vqs,
        .del_vqs        = vp_del_vqs,
        .synchronize_cbs = vp_synchronize_vectors,
-       .get_features   = vp_get_features,
+       .get_extended_features = vp_get_features,
        .finalize_features = vp_finalize_features,
        .bus_name       = vp_bus_name,
        .set_vq_affinity = vp_set_vq_affinity,
@@ -1254,7 +1254,7 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
        .find_vqs       = vp_modern_find_vqs,
        .del_vqs        = vp_del_vqs,
        .synchronize_cbs = vp_synchronize_vectors,
-       .get_features   = vp_get_features,
+       .get_extended_features = vp_get_features,
        .finalize_features = vp_finalize_features,
        .bus_name       = vp_bus_name,
        .set_vq_affinity = vp_set_vq_affinity,

diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index 0d3dbfaf4b236910530b967a3fb9de25b68bcd36..d665f8f73ea86306376b4c776de2db3de95218a1 100644 (file)
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -388,63 +388,74 @@ void vp_modern_remove(struct virtio_pci_modern_device *mdev)
 EXPORT_SYMBOL_GPL(vp_modern_remove);
 
 /*
- * vp_modern_get_features - get features from device
+ * vp_modern_get_extended_features - get features from device
  * @mdev: the modern virtio-pci device
+ * @features: the features array to be filled
  *
- * Returns the features read from the device
+ * Fill the specified features array with the features read from the device
  */
-u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
+void vp_modern_get_extended_features(struct virtio_pci_modern_device *mdev,
+                                    u64 *features)
 {
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
+       int i;
 
-       u64 features;
+       virtio_features_zero(features);
+       for (i = 0; i < VIRTIO_FEATURES_WORDS; i++) {
+               u64 cur;
 
-       vp_iowrite32(0, &cfg->device_feature_select);
-       features = vp_ioread32(&cfg->device_feature);
-       vp_iowrite32(1, &cfg->device_feature_select);
-       features |= ((u64)vp_ioread32(&cfg->device_feature) << 32);
-
-       return features;
+               vp_iowrite32(i, &cfg->device_feature_select);
+               cur = vp_ioread32(&cfg->device_feature);
+               features[i >> 1] |= cur << (32 * (i & 1));
+       }
 }
-EXPORT_SYMBOL_GPL(vp_modern_get_features);
+EXPORT_SYMBOL_GPL(vp_modern_get_extended_features);
 
 /*
  * vp_modern_get_driver_features - get driver features from device
  * @mdev: the modern virtio-pci device
+ * @features: the features array to be filled
  *
- * Returns the driver features read from the device
+ * Fill the specified features array with the driver features read from the
+ * device
  */
-u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev)
+void
+vp_modern_get_driver_extended_features(struct virtio_pci_modern_device *mdev,
+                                      u64 *features)
 {
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
+       int i;
 
-       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);
+       virtio_features_zero(features);
+       for (i = 0; i < VIRTIO_FEATURES_WORDS; i++) {
+               u64 cur;
 
-       return features;
+               vp_iowrite32(i, &cfg->guest_feature_select);
+               cur = vp_ioread32(&cfg->guest_feature);
+               features[i >> 1] |= cur << (32 * (i & 1));
+       }
 }
-EXPORT_SYMBOL_GPL(vp_modern_get_driver_features);
+EXPORT_SYMBOL_GPL(vp_modern_get_driver_extended_features);
 
 /*
- * vp_modern_set_features - set features to device
+ * vp_modern_set_extended_features - set features to device
  * @mdev: the modern virtio-pci device
  * @features: the features set to device
  */
-void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
-                           u64 features)
+void vp_modern_set_extended_features(struct virtio_pci_modern_device *mdev,
+                                    const u64 *features)
 {
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
+       int i;
+
+       for (i = 0; i < VIRTIO_FEATURES_WORDS; i++) {
+               u32 cur = features[i >> 1] >> (32 * (i & 1));
 
-       vp_iowrite32(0, &cfg->guest_feature_select);
-       vp_iowrite32((u32)features, &cfg->guest_feature);
-       vp_iowrite32(1, &cfg->guest_feature_select);
-       vp_iowrite32(features >> 32, &cfg->guest_feature);
+               vp_iowrite32(i, &cfg->guest_feature_select);
+               vp_iowrite32(cur, &cfg->guest_feature);
+       }
 }
-EXPORT_SYMBOL_GPL(vp_modern_set_features);
+EXPORT_SYMBOL_GPL(vp_modern_set_extended_features);
 
 /*
  * vp_modern_generation - get the device genreation

diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
index c0b1b1ca1163507dddca0870a46c93194ae07e75..48bc12d1045bd5a0619ec98d144dccc81ce3156f 100644 (file)
--- a/include/linux/virtio_pci_modern.h
+++ b/include/linux/virtio_pci_modern.h
@@ -3,6 +3,7 @@
 #define _LINUX_VIRTIO_PCI_MODERN_H
 
 #include <linux/pci.h>
+#include <linux/virtio_config.h>
 #include <linux/virtio_pci.h>
 
 /**
@@ -95,10 +96,44 @@ static inline void vp_iowrite64_twopart(u64 val,
        vp_iowrite32(val >> 32, hi);
 }
 
-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);
+void
+vp_modern_get_driver_extended_features(struct virtio_pci_modern_device *mdev,
+                                      u64 *features);
+void vp_modern_get_extended_features(struct virtio_pci_modern_device *mdev,
+                                    u64 *features);
+void vp_modern_set_extended_features(struct virtio_pci_modern_device *mdev,
+                                    const u64 *features);
+
+static inline u64
+vp_modern_get_features(struct virtio_pci_modern_device *mdev)
+{
+       u64 features_array[VIRTIO_FEATURES_DWORDS];
+
+       vp_modern_get_extended_features(mdev, features_array);
+       return features_array[0];
+}
+
+static inline u64
+vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev)
+{
+       u64 features_array[VIRTIO_FEATURES_DWORDS];
+       int i;
+
+       vp_modern_get_driver_extended_features(mdev, features_array);
+       for (i = 1; i < VIRTIO_FEATURES_DWORDS; ++i)
+               WARN_ON_ONCE(features_array[i]);
+       return features_array[0];
+}
+
+static inline void
+vp_modern_set_features(struct virtio_pci_modern_device *mdev, u64 features)
+{
+       u64 features_array[VIRTIO_FEATURES_DWORDS];
+
+       virtio_features_from_u64(features_array, features);
+       vp_modern_set_extended_features(mdev, features_array);
+}
+
 u32 vp_modern_generation(struct virtio_pci_modern_device *mdev);
 u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev);
 void vp_modern_set_status(struct virtio_pci_modern_device *mdev,