vDPA/ifcvf: get_driver_features from virtio registers

This commit implements a new function ifcvf_get_driver_feature()
which read driver_features from virtio registers.

To be less ambiguous, ifcvf_set_features() is renamed to
ifcvf_set_driver_features(), and ifcvf_get_features()
is renamed to ifcvf_get_dev_features() which returns
the provisioned vDPA device features.
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230526145254.39537-3-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/ifcvf/ifcvf_base.c

@@ -204,11 +204,29 @@ u64 ifcvf_get_hw_features(struct ifcvf_hw *hw)
 	return features;
 }
 
-u64 ifcvf_get_features(struct ifcvf_hw *hw)
+/* return provisioned vDPA dev features */
+u64 ifcvf_get_dev_features(struct ifcvf_hw *hw)
 {
 	return hw->dev_features;
 }
 
+u64 ifcvf_get_driver_features(struct ifcvf_hw *hw)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
+	u32 features_lo, features_hi;
+	u64 features;
+
+	vp_iowrite32(0, &cfg->device_feature_select);
+	features_lo = vp_ioread32(&cfg->guest_feature);
+
+	vp_iowrite32(1, &cfg->device_feature_select);
+	features_hi = vp_ioread32(&cfg->guest_feature);
+
+	features = ((u64)features_hi << 32) | features_lo;
+
+	return features;
+}
+
 int ifcvf_verify_min_features(struct ifcvf_hw *hw, u64 features)
 {
 	if (!(features & BIT_ULL(VIRTIO_F_ACCESS_PLATFORM)) && features) {
@@ -275,7 +293,7 @@ void ifcvf_write_dev_config(struct ifcvf_hw *hw, u64 offset,
 		vp_iowrite8(*p++, hw->dev_cfg + offset + i);
 }
 
-static void ifcvf_set_features(struct ifcvf_hw *hw, u64 features)
+void ifcvf_set_driver_features(struct ifcvf_hw *hw, u64 features)
 {
 	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
 
@@ -286,19 +304,6 @@ static void ifcvf_set_features(struct ifcvf_hw *hw, u64 features)
 	vp_iowrite32(features >> 32, &cfg->guest_feature);
 }
 
-static int ifcvf_config_features(struct ifcvf_hw *hw)
-{
-	ifcvf_set_features(hw, hw->req_features);
-	ifcvf_add_status(hw, VIRTIO_CONFIG_S_FEATURES_OK);
-
-	if (!(ifcvf_get_status(hw) & VIRTIO_CONFIG_S_FEATURES_OK)) {
-		IFCVF_ERR(hw->pdev, "Failed to set FEATURES_OK status\n");
-		return -EIO;
-	}
-
-	return 0;
-}
-
 u16 ifcvf_get_vq_state(struct ifcvf_hw *hw, u16 qid)
 {
 	struct ifcvf_lm_cfg __iomem *ifcvf_lm;
@@ -387,9 +392,6 @@ int ifcvf_start_hw(struct ifcvf_hw *hw)
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_ACKNOWLEDGE);
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER);
 
-	if (ifcvf_config_features(hw) < 0)
-		return -EINVAL;
-
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER_OK);
 
 	return 0;

drivers/vdpa/ifcvf/ifcvf_base.h

@@ -69,7 +69,6 @@ struct ifcvf_hw {
 	phys_addr_t notify_base_pa;
 	u32 notify_off_multiplier;
 	u32 dev_type;
-	u64 req_features;
 	u64 hw_features;
 	/* provisioned device features */
 	u64 dev_features;
@@ -122,7 +121,7 @@ u8 ifcvf_get_status(struct ifcvf_hw *hw);
 void ifcvf_set_status(struct ifcvf_hw *hw, u8 status);
 void io_write64_twopart(u64 val, u32 *lo, u32 *hi);
 void ifcvf_reset(struct ifcvf_hw *hw);
-u64 ifcvf_get_features(struct ifcvf_hw *hw);
+u64 ifcvf_get_dev_features(struct ifcvf_hw *hw);
 u64 ifcvf_get_hw_features(struct ifcvf_hw *hw);
 int ifcvf_verify_min_features(struct ifcvf_hw *hw, u64 features);
 u16 ifcvf_get_vq_state(struct ifcvf_hw *hw, u16 qid);
@@ -137,4 +136,6 @@ int ifcvf_set_vq_address(struct ifcvf_hw *hw, u16 qid, u64 desc_area,
 			 u64 driver_area, u64 device_area);
 bool ifcvf_get_vq_ready(struct ifcvf_hw *hw, u16 qid);
 void ifcvf_set_vq_ready(struct ifcvf_hw *hw, u16 qid, bool ready);
+void ifcvf_set_driver_features(struct ifcvf_hw *hw, u64 features);
+u64 ifcvf_get_driver_features(struct ifcvf_hw *hw);
 #endif /* _IFCVF_H_ */

drivers/vdpa/ifcvf/ifcvf_main.c

@@ -410,7 +410,7 @@ static u64 ifcvf_vdpa_get_device_features(struct vdpa_device *vdpa_dev)
 	u64 features;
 
 	if (type == VIRTIO_ID_NET || type == VIRTIO_ID_BLOCK)
-		features = ifcvf_get_features(vf);
+		features = ifcvf_get_dev_features(vf);
 	else {
 		features = 0;
 		IFCVF_ERR(pdev, "VIRTIO ID %u not supported\n", vf->dev_type);
@@ -428,7 +428,7 @@ static int ifcvf_vdpa_set_driver_features(struct vdpa_device *vdpa_dev, u64 feat
 	if (ret)
 		return ret;
 
-	vf->req_features = features;
+	ifcvf_set_driver_features(vf, features);
 
 	return 0;
 }
@@ -436,8 +436,11 @@ static int ifcvf_vdpa_set_driver_features(struct vdpa_device *vdpa_dev, u64 feat
 static u64 ifcvf_vdpa_get_driver_features(struct vdpa_device *vdpa_dev)
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
+	u64 features;
+
+	features = ifcvf_get_driver_features(vf);
 
-	return vf->req_features;
+	return features;
 }
 
 static u8 ifcvf_vdpa_get_status(struct vdpa_device *vdpa_dev)