Date:   Mon, 11 Apr 2022 11:10:57 +0800
From:   Zhu Lingshan <lingshan.zhu@...el.com>
To:     jasowang@...hat.com, mst@...hat.com
Cc:     virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        Zhu Lingshan <lingshan.zhu@...el.com>
Subject: [PATCH] vDPA/ifcvf: allow userspace to suspend a queue

Formerly, ifcvf driver has implemented a lazy-initialization mechanism
for the virtqueues, it would store all virtqueue config fields that
passed down from the userspace, then load them to the virtqueues and
enable the queues upon DRIVER_OK.

To allow the userspace to suspend a virtqueue,
this commit passes queue_enable to the virtqueue directly through
set_vq_ready().

This feature requires and this commits implementing all virtqueue
ops(set_vq_addr, set_vq_num and set_vq_ready) to take immediate
actions than lazy-initialization, so ifcvf_hw_enable() is retired.

To avoid losing virtqueue configurations caused by multiple
rounds of reset(), this commit also refactors thed evice reset
routine, now it simply reset the config handler and the virtqueues,
and only once device-reset().

Signed-off-by: Zhu Lingshan <lingshan.zhu@...el.com>
---
 drivers/vdpa/ifcvf/ifcvf_base.c | 94 ++++++++++++++++++++-------------
 drivers/vdpa/ifcvf/ifcvf_base.h | 11 ++--
 drivers/vdpa/ifcvf/ifcvf_main.c | 57 +++++---------------
 3 files changed, 75 insertions(+), 87 deletions(-)

diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
index 48c4dadb0c7c..19eb0dcac123 100644
--- a/drivers/vdpa/ifcvf/ifcvf_base.c
+++ b/drivers/vdpa/ifcvf/ifcvf_base.c
@@ -175,16 +175,12 @@ u8 ifcvf_get_status(struct ifcvf_hw *hw)
 void ifcvf_set_status(struct ifcvf_hw *hw, u8 status)
 {
 	vp_iowrite8(status, &hw->common_cfg->device_status);
+	vp_ioread8(&hw->common_cfg->device_status);
 }
 
 void ifcvf_reset(struct ifcvf_hw *hw)
 {
-	hw->config_cb.callback = NULL;
-	hw->config_cb.private = NULL;
-
 	ifcvf_set_status(hw, 0);
-	/* flush set_status, make sure VF is stopped, reset */
-	ifcvf_get_status(hw);
 }
 
 static void ifcvf_add_status(struct ifcvf_hw *hw, u8 status)
@@ -331,68 +327,94 @@ int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num)
 	ifcvf_lm = (struct ifcvf_lm_cfg __iomem *)hw->lm_cfg;
 	q_pair_id = qid / hw->nr_vring;
 	avail_idx_addr = &ifcvf_lm->vring_lm_cfg[q_pair_id].idx_addr[qid % 2];
-	hw->vring[qid].last_avail_idx = num;
 	vp_iowrite16(num, avail_idx_addr);
+	vp_ioread16(avail_idx_addr);
 
 	return 0;
 }
 
-static int ifcvf_hw_enable(struct ifcvf_hw *hw)
+void ifcvf_set_vq_num(struct ifcvf_hw *hw, u16 qid, u32 num)
 {
-	struct virtio_pci_common_cfg __iomem *cfg;
-	u32 i;
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
 
-	cfg = hw->common_cfg;
-	for (i = 0; i < hw->nr_vring; i++) {
-		if (!hw->vring[i].ready)
-			break;
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite16(num, &cfg->queue_size);
+	vp_ioread16(&cfg->queue_size);
+}
 
-		vp_iowrite16(i, &cfg->queue_select);
-		vp_iowrite64_twopart(hw->vring[i].desc, &cfg->queue_desc_lo,
-				     &cfg->queue_desc_hi);
-		vp_iowrite64_twopart(hw->vring[i].avail, &cfg->queue_avail_lo,
-				      &cfg->queue_avail_hi);
-		vp_iowrite64_twopart(hw->vring[i].used, &cfg->queue_used_lo,
-				     &cfg->queue_used_hi);
-		vp_iowrite16(hw->vring[i].size, &cfg->queue_size);
-		ifcvf_set_vq_state(hw, i, hw->vring[i].last_avail_idx);
-		vp_iowrite16(1, &cfg->queue_enable);
-	}
+int ifcvf_set_vq_address(struct ifcvf_hw *hw, u16 qid, u64 desc_area,
+			 u64 driver_area, u64 device_area)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
+
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite64_twopart(desc_area, &cfg->queue_desc_lo,
+			     &cfg->queue_desc_hi);
+	vp_iowrite64_twopart(driver_area, &cfg->queue_avail_lo,
+			     &cfg->queue_avail_hi);
+	vp_iowrite64_twopart(device_area, &cfg->queue_used_lo,
+			     &cfg->queue_used_hi);
+	/* to flush IO */
+	vp_ioread16(&cfg->queue_select);
 
 	return 0;
 }
 
-static void ifcvf_hw_disable(struct ifcvf_hw *hw)
+void ifcvf_set_vq_ready(struct ifcvf_hw *hw, u16 qid, bool ready)
 {
-	u32 i;
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
 
-	ifcvf_set_config_vector(hw, VIRTIO_MSI_NO_VECTOR);
-	for (i = 0; i < hw->nr_vring; i++) {
-		ifcvf_set_vq_vector(hw, i, VIRTIO_MSI_NO_VECTOR);
-	}
+	vp_iowrite16(qid, &cfg->queue_select);
+	vp_iowrite16(ready, &cfg->queue_enable);
+	vp_ioread16(&cfg->queue_enable);
+}
+
+bool ifcvf_get_vq_ready(struct ifcvf_hw *hw, u16 qid)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
+	bool queue_enable;
+
+	vp_iowrite16(qid, &cfg->queue_select);
+	queue_enable = vp_ioread16(&cfg->queue_enable);
+
+	return (bool)queue_enable;
 }
 
 int ifcvf_start_hw(struct ifcvf_hw *hw)
 {
-	ifcvf_reset(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;
 
-	if (ifcvf_hw_enable(hw) < 0)
-		return -EINVAL;
-
 	ifcvf_add_status(hw, VIRTIO_CONFIG_S_DRIVER_OK);
 
 	return 0;
 }
 
+static void ifcvf_reset_vring(struct ifcvf_hw *hw)
+{
+	int i;
+
+	for (i = 0; i < hw->nr_vring; i++) {
+		hw->vring[i].cb.callback = NULL;
+		hw->vring[i].cb.private = NULL;
+		ifcvf_set_vq_vector(hw, i, VIRTIO_MSI_NO_VECTOR);
+	}
+}
+
+static void ifcvf_reset_config_handler(struct ifcvf_hw *hw)
+{
+	hw->config_cb.callback = NULL;
+	hw->config_cb.private = NULL;
+	ifcvf_set_config_vector(hw, VIRTIO_MSI_NO_VECTOR);
+}
+
 void ifcvf_stop_hw(struct ifcvf_hw *hw)
 {
-	ifcvf_hw_disable(hw);
-	ifcvf_reset(hw);
+	ifcvf_reset_vring(hw);
+	ifcvf_reset_config_handler(hw);
 }
 
 void ifcvf_notify_queue(struct ifcvf_hw *hw, u16 qid)
diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h
index 115b61f4924b..41d86985361f 100644
--- a/drivers/vdpa/ifcvf/ifcvf_base.h
+++ b/drivers/vdpa/ifcvf/ifcvf_base.h
@@ -49,12 +49,6 @@
 #define MSIX_VECTOR_DEV_SHARED			3
 
 struct vring_info {
-	u64 desc;
-	u64 avail;
-	u64 used;
-	u16 size;
-	u16 last_avail_idx;
-	bool ready;
 	void __iomem *notify_addr;
 	phys_addr_t notify_pa;
 	u32 irq;
@@ -131,6 +125,11 @@ int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num);
 struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw);
 int ifcvf_probed_virtio_net(struct ifcvf_hw *hw);
 u32 ifcvf_get_config_size(struct ifcvf_hw *hw);
+int ifcvf_set_vq_address(struct ifcvf_hw *hw, u16 qid, u64 desc_area,
+			 u64 driver_area, u64 device_area);
 u16 ifcvf_set_vq_vector(struct ifcvf_hw *hw, u16 qid, int vector);
 u16 ifcvf_set_config_vector(struct ifcvf_hw *hw, int vector);
+void ifcvf_set_vq_num(struct ifcvf_hw *hw, u16 qid, u32 num);
+void ifcvf_set_vq_ready(struct ifcvf_hw *hw, u16 qid, bool ready);
+bool ifcvf_get_vq_ready(struct ifcvf_hw *hw, u16 qid);
 #endif /* _IFCVF_H_ */
diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
index 4366320fb68d..e442aa11333e 100644
--- a/drivers/vdpa/ifcvf/ifcvf_main.c
+++ b/drivers/vdpa/ifcvf/ifcvf_main.c
@@ -374,37 +374,6 @@ static int ifcvf_start_datapath(void *private)
 	return ret;
 }
 
-static int ifcvf_stop_datapath(void *private)
-{
-	struct ifcvf_hw *vf = ifcvf_private_to_vf(private);
-	int i;
-
-	for (i = 0; i < vf->nr_vring; i++)
-		vf->vring[i].cb.callback = NULL;
-
-	ifcvf_stop_hw(vf);
-
-	return 0;
-}
-
-static void ifcvf_reset_vring(struct ifcvf_adapter *adapter)
-{
-	struct ifcvf_hw *vf = ifcvf_private_to_vf(adapter);
-	int i;
-
-	for (i = 0; i < vf->nr_vring; i++) {
-		vf->vring[i].last_avail_idx = 0;
-		vf->vring[i].desc = 0;
-		vf->vring[i].avail = 0;
-		vf->vring[i].used = 0;
-		vf->vring[i].ready = 0;
-		vf->vring[i].cb.callback = NULL;
-		vf->vring[i].cb.private = NULL;
-	}
-
-	ifcvf_reset(vf);
-}
-
 static struct ifcvf_adapter *vdpa_to_adapter(struct vdpa_device *vdpa_dev)
 {
 	return container_of(vdpa_dev, struct ifcvf_adapter, vdpa);
@@ -477,6 +446,8 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)
 	if (status_old == status)
 		return;
 
+	ifcvf_set_status(vf, status);
+
 	if ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&
 	    !(status_old & VIRTIO_CONFIG_S_DRIVER_OK)) {
 		ret = ifcvf_request_irq(adapter);
@@ -493,7 +464,6 @@ static void ifcvf_vdpa_set_status(struct vdpa_device *vdpa_dev, u8 status)
 				  status);
 	}
 
-	ifcvf_set_status(vf, status);
 }
 
 static int ifcvf_vdpa_reset(struct vdpa_device *vdpa_dev)
@@ -509,12 +479,10 @@ static int ifcvf_vdpa_reset(struct vdpa_device *vdpa_dev)
 	if (status_old == 0)
 		return 0;
 
-	if (status_old & VIRTIO_CONFIG_S_DRIVER_OK) {
-		ifcvf_stop_datapath(adapter);
-		ifcvf_free_irq(adapter);
-	}
+	ifcvf_stop_hw(vf);
+	ifcvf_free_irq(adapter);
 
-	ifcvf_reset_vring(adapter);
+	ifcvf_reset(vf);
 
 	return 0;
 }
@@ -554,14 +522,17 @@ static void ifcvf_vdpa_set_vq_ready(struct vdpa_device *vdpa_dev,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	vf->vring[qid].ready = ready;
+	ifcvf_set_vq_ready(vf, qid, ready);
 }
 
 static bool ifcvf_vdpa_get_vq_ready(struct vdpa_device *vdpa_dev, u16 qid)
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
+	bool ready;
 
-	return vf->vring[qid].ready;
+	ready = ifcvf_get_vq_ready(vf, qid);
+
+	return ready;
 }
 
 static void ifcvf_vdpa_set_vq_num(struct vdpa_device *vdpa_dev, u16 qid,
@@ -569,7 +540,7 @@ static void ifcvf_vdpa_set_vq_num(struct vdpa_device *vdpa_dev, u16 qid,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	vf->vring[qid].size = num;
+	ifcvf_set_vq_num(vf, qid, num);
 }
 
 static int ifcvf_vdpa_set_vq_address(struct vdpa_device *vdpa_dev, u16 qid,
@@ -578,11 +549,7 @@ static int ifcvf_vdpa_set_vq_address(struct vdpa_device *vdpa_dev, u16 qid,
 {
 	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
 
-	vf->vring[qid].desc = desc_area;
-	vf->vring[qid].avail = driver_area;
-	vf->vring[qid].used = device_area;
-
-	return 0;
+	return ifcvf_set_vq_address(vf, qid, desc_area, driver_area, device_area);
 }
 
 static void ifcvf_vdpa_kick_vq(struct vdpa_device *vdpa_dev, u16 qid)
-- 
2.31.1

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