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Commit 7c177596 authored by Chris Lew's avatar Chris Lew
Browse files

soc: qcom: guestvm_loader: Wait for ready state before start 



The ready state gives clients in the primary vm a chance to share
resources before the vm is started and set to running state. This
window is currently missing because guestvm_loader starts the vm
directly after subsystem_get().

Make the guestvm boot code wait for the HH_RM_VM_STATUS_READY callback
before starting the vm. This allows drivers that need to share
resources a chance to do so instead of racing with guestvm_loader.
Drivers can register with the rm notifier chain at a higher priority
than 0 to be called first.

This change can eventually be replaced by a separate driver or notifier
chain managed by guestvm_loader to provide better synchronization
methods compared to notifier chain priority.

Change-Id: I0fb3c5c41957381b31fa652deec0d6d51a41e6ef
Signed-off-by: default avatarChris Lew <clew@codeaurora.org>
parent bbc7f2d3

drivers/soc/qcom/guestvm_loader.c

+9 −1
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
 * Copyright (c) 2020, The Linux Foundation. All rights reserved.

 */



#include <linux/completion.h>

#include <linux/list.h>

#include <linux/kernel.h>

#include <linux/module.h>
@@ -31,6 +32,7 @@ static struct kobj_type guestvm_kobj_type = { 


struct guestvm_loader_private {

	struct notifier_block guestvm_nb;

	struct completion vm_start;

	struct kobject vm_loader_kobj;

	struct device *dev;

	char vm_name[MAX_LEN];
@@ -82,6 +84,7 @@ static int guestvm_loader_nb_handler(struct notifier_block *this, 
				vm_status_payload->vmid, ret);

			return NOTIFY_DONE;

		}

		complete_all(&priv->vm_start);

		break;

	case HH_RM_VM_STATUS_RUNNING:

		break;
@@ -129,6 +132,8 @@ static ssize_t guestvm_loader_start(struct kobject *kobj, 
			priv->vm_loaded = NULL;

			return ret;

		}

		if (wait_for_completion_interruptible(&priv->vm_start))

			dev_err(priv->dev, "VM start completion interrupted\n");



		priv->vm_status = HH_RM_VM_STATUS_RUNNING;

		ret = hh_rm_vm_start(priv->vmid);
@@ -184,6 +189,7 @@ static int guestvm_loader_probe(struct platform_device *pdev) 
		goto error_return;

	}



	init_completion(&priv->vm_start);

	priv->guestvm_nb.notifier_call = guestvm_loader_nb_handler;

	ret = hh_rm_register_notifier(&priv->guestvm_nb);

	if (ret)
@@ -207,8 +213,10 @@ static int guestvm_loader_remove(struct platform_device *pdev) 
{

	struct guestvm_loader_private *priv = platform_get_drvdata(pdev);



	if (priv->vm_loaded)

	if (priv->vm_loaded) {

		subsystem_put(priv->vm_loaded);

		init_completion(&priv->vm_start);

	}



	if (kobject_name(&priv->vm_loader_kobj) != NULL) {

		kobject_del(&priv->vm_loader_kobj);