vDPA/ifcvf: fetch device feature bits when probe

This commit would read and store device feature
bits when probe.

rename ifcvf_get_features() to ifcvf_get_hw_features(),
it reads and stores features of the probed device.

new ifcvf_get_features() simply returns stored
feature bits.
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210317094933.16417-6-lingshan.zhu@intel.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/ifcvf/ifcvf_base.c

@@ -202,10 +202,11 @@ static void ifcvf_add_status(struct ifcvf_hw *hw, u8 status)
 	ifcvf_get_status(hw);
 }
 
-u64 ifcvf_get_features(struct ifcvf_hw *hw)
+u64 ifcvf_get_hw_features(struct ifcvf_hw *hw)
 {
 	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
 	u32 features_lo, features_hi;
+	u64 features;
 
 	ifc_iowrite32(0, &cfg->device_feature_select);
 	features_lo = ifc_ioread32(&cfg->device_feature);
@@ -213,7 +214,14 @@ u64 ifcvf_get_features(struct ifcvf_hw *hw)
 	ifc_iowrite32(1, &cfg->device_feature_select);
 	features_hi = ifc_ioread32(&cfg->device_feature);
 
-	return ((u64)features_hi << 32) | features_lo;
+	features = ((u64)features_hi << 32) | features_lo;
+
+	return features;
+}
+
+u64 ifcvf_get_features(struct ifcvf_hw *hw)
+{
+	return hw->hw_features;
 }
 
 void ifcvf_read_net_config(struct ifcvf_hw *hw, u64 offset,

drivers/vdpa/ifcvf/ifcvf_base.h

@@ -83,6 +83,7 @@ struct ifcvf_hw {
 	void __iomem *notify_base;
 	u32 notify_off_multiplier;
 	u64 req_features;
+	u64 hw_features;
 	struct virtio_pci_common_cfg __iomem *common_cfg;
 	void __iomem *net_cfg;
 	struct vring_info vring[IFCVF_MAX_QUEUE_PAIRS * 2];
@@ -121,6 +122,7 @@ 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_hw_features(struct ifcvf_hw *hw);
 u16 ifcvf_get_vq_state(struct ifcvf_hw *hw, u16 qid);
 int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num);
 struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw);

drivers/vdpa/ifcvf/ifcvf_main.c

@@ -457,6 +457,8 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++)
 		vf->vring[i].irq = -EINVAL;
 
+	vf->hw_features = ifcvf_get_hw_features(vf);
+
 	ret = vdpa_register_device(&adapter->vdpa, IFCVF_MAX_QUEUE_PAIRS * 2);
 	if (ret) {
 		IFCVF_ERR(pdev, "Failed to register ifcvf to vdpa bus");