clear-pkgs-linux-iot-lts2018/0755-vhm-Add-ioctl-IC_CLEAR_VM_IOREQ-to-cleanup-VM-ioreqs.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shuo Liu <shuo.a.liu@intel.com>
Date: Fri, 12 Oct 2018 17:29:35 +0800
Subject: [PATCH] vhm: Add ioctl IC_CLEAR_VM_IOREQ to cleanup VM ioreqs

DM need cleanup all ioreqs of the VM in some situations, such as VM
reset. This ioctl should be used after VM paused as there is not new
ioreqs. The call is synchronous waiting for ioreqs(except DM's)
completed and reset their status in VHM. DM ones pending ioreqs will be
completed directly without handle.

Tracked-On: PKT-1592
Tracked-On: projectacrn/acrn-hypervisor#1821
Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Reviewed-by: Zhao, Yakui <yakui.zhao@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
---
 drivers/char/vhm/vhm_dev.c         | 18 +++++++++
 drivers/vhm/vhm_ioreq.c            | 59 ++++++++++++++++++++++++++----
 include/linux/vhm/acrn_vhm_ioreq.h |  9 +++++
 include/linux/vhm/vhm_ioctl_defs.h |  1 +
 4 files changed, 79 insertions(+), 8 deletions(-)

diff --git a/drivers/char/vhm/vhm_dev.c b/drivers/char/vhm/vhm_dev.c
index dbed2dfbde65..6970def28b0c 100644
--- a/drivers/char/vhm/vhm_dev.c
+++ b/drivers/char/vhm/vhm_dev.c
@@ -395,6 +395,24 @@ static long vhm_dev_ioctl(struct file *filep,
 		break;
 	}
 
+	case IC_CLEAR_VM_IOREQ: {
+		/*
+		 * TODO: Query VM status with additional hypercall.
+		 * VM should be in paused status.
+		 *
+		 * In SMP SOS, we need flush the current pending ioreq dispatch
+		 * tasklet and finish it before clearing all ioreq of this VM.
+		 * With tasklet_kill, there still be a very rare race which
+		 * might lost one ioreq tasklet for other VMs. So arm one after
+		 * the clearing. It's harmless.
+		 */
+		tasklet_schedule(&vhm_io_req_tasklet);
+		tasklet_kill(&vhm_io_req_tasklet);
+		tasklet_schedule(&vhm_io_req_tasklet);
+		acrn_ioreq_clear_request(vm);
+		break;
+	}
+
 	case IC_SET_IRQLINE: {
 		ret = hcall_set_irqline(vm->vmid, ioctl_param);
 		if (ret < 0) {
diff --git a/drivers/vhm/vhm_ioreq.c b/drivers/vhm/vhm_ioreq.c
index ff19cc3b76ba..1759fd43b2fd 100644
--- a/drivers/vhm/vhm_ioreq.c
+++ b/drivers/vhm/vhm_ioreq.c
@@ -135,6 +135,14 @@ static inline bool is_range_type(uint32_t type)
 	return (type == REQ_MMIO || type == REQ_PORTIO || type == REQ_WP);
 }
 
+static inline bool has_pending_request(struct ioreq_client *client)
+{
+	if (client)
+		return !bitmap_empty(client->ioreqs_map, VHM_REQUEST_MAX);
+	else
+		return false;
+}
+
 static int alloc_client(void)
 {
 	struct ioreq_client *client;
@@ -222,6 +230,49 @@ int acrn_ioreq_create_client(unsigned long vmid, ioreq_handler_t handler,
 }
 EXPORT_SYMBOL_GPL(acrn_ioreq_create_client);
 
+void acrn_ioreq_clear_request(struct vhm_vm *vm)
+{
+	struct ioreq_client *client;
+	struct list_head *pos;
+	bool has_pending = false;
+	int retry_cnt = 10;
+	int bit;
+
+	/*
+	 * Now, ioreq clearing only happens when do VM reset. Current
+	 * implementation is waiting all ioreq clients except the DM
+	 * one have no pending ioreqs in 10ms per loop
+	 */
+
+	do {
+		spin_lock(&vm->ioreq_client_lock);
+		list_for_each(pos, &vm->ioreq_client_list) {
+			client = container_of(pos, struct ioreq_client, list);
+			if (vm->ioreq_fallback_client == client->id)
+				continue;
+			has_pending = has_pending_request(client);
+			if (has_pending)
+				break;
+		}
+		spin_unlock(&vm->ioreq_client_lock);
+
+		if (has_pending)
+			schedule_timeout_interruptible(HZ / 100);
+	} while (has_pending && --retry_cnt > 0);
+
+	if (retry_cnt == 0)
+		pr_warn("ioreq client[%d] cannot flush pending request!\n",
+				client->id);
+
+	/* Clear all ioreqs belong to DM. */
+	if (vm->ioreq_fallback_client > 0) {
+		client = clients[vm->ioreq_fallback_client];
+		while ((bit = find_next_bit(client->ioreqs_map,
+				0, VHM_REQUEST_MAX)) ==	VHM_REQUEST_MAX)
+			acrn_ioreq_complete_request(client->id, bit);
+	}
+}
+
 int acrn_ioreq_create_fallback_client(unsigned long vmid, char *name)
 {
 	struct vhm_vm *vm;
@@ -437,14 +488,6 @@ static inline bool is_destroying(struct ioreq_client *client)
 		return true;
 }
 
-static inline bool has_pending_request(struct ioreq_client *client)
-{
-	if (client)
-		return !bitmap_empty(client->ioreqs_map, VHM_REQUEST_MAX);
-	else
-		return false;
-}
-
 struct vhm_request *acrn_ioreq_get_reqbuf(int client_id)
 {
 	struct ioreq_client *client;
diff --git a/include/linux/vhm/acrn_vhm_ioreq.h b/include/linux/vhm/acrn_vhm_ioreq.h
index 52b3ac83203c..5b32f153c050 100644
--- a/include/linux/vhm/acrn_vhm_ioreq.h
+++ b/include/linux/vhm/acrn_vhm_ioreq.h
@@ -160,6 +160,15 @@ int acrn_ioreq_distribute_request(struct vhm_vm *vm);
  */
 int acrn_ioreq_complete_request(int client_id, uint64_t vcpu);
 
+/**
+ * acrn_ioreq_clear_request - clear all guest requests
+ *
+ * @vm: pointer to guest VM
+ *
+ * Return:
+ */
+void acrn_ioreq_clear_request(struct vhm_vm *vm);
+
 /**
  * acrn_ioreq_intercept_bdf - set intercept bdf info of ioreq client
  *
diff --git a/include/linux/vhm/vhm_ioctl_defs.h b/include/linux/vhm/vhm_ioctl_defs.h
index 19ebf54e57f3..a98b003762b5 100644
--- a/include/linux/vhm/vhm_ioctl_defs.h
+++ b/include/linux/vhm/vhm_ioctl_defs.h
@@ -88,6 +88,7 @@
 #define IC_CREATE_IOREQ_CLIENT          _IC_ID(IC_ID, IC_ID_IOREQ_BASE + 0x02)
 #define IC_ATTACH_IOREQ_CLIENT          _IC_ID(IC_ID, IC_ID_IOREQ_BASE + 0x03)
 #define IC_DESTROY_IOREQ_CLIENT         _IC_ID(IC_ID, IC_ID_IOREQ_BASE + 0x04)
+#define IC_CLEAR_VM_IOREQ               _IC_ID(IC_ID, IC_ID_IOREQ_BASE + 0x05)
 
 /* Guest memory management */
 #define IC_ID_MEM_BASE                  0x40UL
-- 
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