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From: Elliot Berman <quic_eberman@quicinc.com>
Date: Fri, 15 Dec 2023 16:20:51 -0800
Subject: [PATCH RFC v15 10/30] gunyah: vm_mgr: Add ioctls to support basic
 non-proxy VM boot
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Message-ID: <20231215-gunyah-v15-10-192a5d872a30@quicinc.com>
References: <20231215-gunyah-v15-0-192a5d872a30@quicinc.com>
In-Reply-To: <20231215-gunyah-v15-0-192a5d872a30@quicinc.com>
To: Alex Elder <elder@linaro.org>,
        Srinivas Kandagatla
	<srinivas.kandagatla@linaro.org>,
        Murali Nalajal <quic_mnalajal@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Srivatsa Vaddagiri
	<quic_svaddagi@quicinc.com>,
        Carl van Schaik <quic_cvanscha@quicinc.com>,
        Philip Derrin <quic_pderrin@quicinc.com>,
        Prakruthi Deepak Heragu
	<quic_pheragu@quicinc.com>,
        Jonathan Corbet <corbet@lwn.net>, Rob Herring
	<robh+dt@kernel.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Bjorn Andersson
	<andersson@kernel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        "Fuad
 Tabba" <tabba@google.com>,
        Sean Christopherson <seanjc@google.com>
CC: <linux-arm-msm@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        Elliot Berman
	<quic_eberman@quicinc.com>

Add remaining ioctls to support non-proxy VM boot:

 - Gunyah Resource Manager uses the VM's devicetree to configure the
   virtual machine. The location of the devicetree in the guest's
   virtual memory can be declared via the SET_DTB_CONFIG ioctl.
 - Trigger start of the virtual machine with VM_START ioctl.

Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/vm_mgr.c | 194 +++++++++++++++++++++++++++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.h |  11 +++
 include/uapi/linux/gunyah.h  |   5 ++
 3 files changed, 210 insertions(+)

diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index b4d44379e5ce..1b1b26f568af 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -15,6 +15,68 @@
 
 #include "vm_mgr.h"
 
+static int gunyah_vm_rm_notification_status(struct gunyah_vm *ghvm, void *data)
+{
+	struct gunyah_rm_vm_status_payload *payload = data;
+
+	if (le16_to_cpu(payload->vmid) != ghvm->vmid)
+		return NOTIFY_OK;
+
+	/* All other state transitions are synchronous to a corresponding RM call */
+	if (payload->vm_status == GUNYAH_RM_VM_STATUS_RESET) {
+		down_write(&ghvm->status_lock);
+		ghvm->vm_status = payload->vm_status;
+		up_write(&ghvm->status_lock);
+		wake_up(&ghvm->vm_status_wait);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int gunyah_vm_rm_notification_exited(struct gunyah_vm *ghvm, void *data)
+{
+	struct gunyah_rm_vm_exited_payload *payload = data;
+
+	if (le16_to_cpu(payload->vmid) != ghvm->vmid)
+		return NOTIFY_OK;
+
+	down_write(&ghvm->status_lock);
+	ghvm->vm_status = GUNYAH_RM_VM_STATUS_EXITED;
+	up_write(&ghvm->status_lock);
+	wake_up(&ghvm->vm_status_wait);
+
+	return NOTIFY_DONE;
+}
+
+static int gunyah_vm_rm_notification(struct notifier_block *nb,
+				     unsigned long action, void *data)
+{
+	struct gunyah_vm *ghvm = container_of(nb, struct gunyah_vm, nb);
+
+	switch (action) {
+	case GUNYAH_RM_NOTIFICATION_VM_STATUS:
+		return gunyah_vm_rm_notification_status(ghvm, data);
+	case GUNYAH_RM_NOTIFICATION_VM_EXITED:
+		return gunyah_vm_rm_notification_exited(ghvm, data);
+	default:
+		return NOTIFY_OK;
+	}
+}
+
+static void gunyah_vm_stop(struct gunyah_vm *ghvm)
+{
+	int ret;
+
+	if (ghvm->vm_status == GUNYAH_RM_VM_STATUS_RUNNING) {
+		ret = gunyah_rm_vm_stop(ghvm->rm, ghvm->vmid);
+		if (ret)
+			dev_warn(ghvm->parent, "Failed to stop VM: %d\n", ret);
+	}
+
+	wait_event(ghvm->vm_status_wait,
+		   ghvm->vm_status == GUNYAH_RM_VM_STATUS_EXITED);
+}
+
 static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm)
 {
 	struct gunyah_vm *ghvm;
@@ -24,14 +86,144 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm)
 		return ERR_PTR(-ENOMEM);
 
 	ghvm->parent = gunyah_rm_get(rm);
+	ghvm->vmid = GUNYAH_VMID_INVAL;
 	ghvm->rm = rm;
 
+	init_rwsem(&ghvm->status_lock);
+	init_waitqueue_head(&ghvm->vm_status_wait);
+	ghvm->vm_status = GUNYAH_RM_VM_STATUS_NO_STATE;
+
 	return ghvm;
 }
 
+static int gunyah_vm_start(struct gunyah_vm *ghvm)
+{
+	int ret;
+
+	down_write(&ghvm->status_lock);
+	if (ghvm->vm_status != GUNYAH_RM_VM_STATUS_NO_STATE) {
+		up_write(&ghvm->status_lock);
+		return 0;
+	}
+
+	ghvm->nb.notifier_call = gunyah_vm_rm_notification;
+	ret = gunyah_rm_notifier_register(ghvm->rm, &ghvm->nb);
+	if (ret)
+		goto err;
+
+	ret = gunyah_rm_alloc_vmid(ghvm->rm, 0);
+	if (ret < 0) {
+		gunyah_rm_notifier_unregister(ghvm->rm, &ghvm->nb);
+		goto err;
+	}
+	ghvm->vmid = ret;
+	ghvm->vm_status = GUNYAH_RM_VM_STATUS_LOAD;
+
+	ret = gunyah_rm_vm_configure(ghvm->rm, ghvm->vmid, ghvm->auth, 0, 0, 0,
+				     0, 0);
+	if (ret) {
+		dev_warn(ghvm->parent, "Failed to configure VM: %d\n", ret);
+		goto err;
+	}
+
+	ret = gunyah_rm_vm_init(ghvm->rm, ghvm->vmid);
+	if (ret) {
+		ghvm->vm_status = GUNYAH_RM_VM_STATUS_INIT_FAILED;
+		dev_warn(ghvm->parent, "Failed to initialize VM: %d\n", ret);
+		goto err;
+	}
+	ghvm->vm_status = GUNYAH_RM_VM_STATUS_READY;
+
+	ret = gunyah_rm_vm_start(ghvm->rm, ghvm->vmid);
+	if (ret) {
+		dev_warn(ghvm->parent, "Failed to start VM: %d\n", ret);
+		goto err;
+	}
+
+	ghvm->vm_status = GUNYAH_RM_VM_STATUS_RUNNING;
+	up_write(&ghvm->status_lock);
+	return ret;
+err:
+	/* gunyah_vm_free will handle releasing resources and reclaiming memory */
+	up_write(&ghvm->status_lock);
+	return ret;
+}
+
+static int gunyah_vm_ensure_started(struct gunyah_vm *ghvm)
+{
+	int ret;
+
+	ret = down_read_interruptible(&ghvm->status_lock);
+	if (ret)
+		return ret;
+
+	/* Unlikely because VM is typically started */
+	if (unlikely(ghvm->vm_status == GUNYAH_RM_VM_STATUS_NO_STATE)) {
+		up_read(&ghvm->status_lock);
+		ret = gunyah_vm_start(ghvm);
+		if (ret)
+			return ret;
+		/** gunyah_vm_start() is guaranteed to bring status out of
+		 * GUNYAH_RM_VM_STATUS_LOAD, thus infinitely recursive call is not
+		 * possible
+		 */
+		return gunyah_vm_ensure_started(ghvm);
+	}
+
+	/* Unlikely because VM is typically running */
+	if (unlikely(ghvm->vm_status != GUNYAH_RM_VM_STATUS_RUNNING))
+		ret = -ENODEV;
+
+	up_read(&ghvm->status_lock);
+	return ret;
+}
+
+static long gunyah_vm_ioctl(struct file *filp, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct gunyah_vm *ghvm = filp->private_data;
+	long r;
+
+	switch (cmd) {
+	case GUNYAH_VM_START: {
+		r = gunyah_vm_ensure_started(ghvm);
+		break;
+	}
+	default:
+		r = -ENOTTY;
+		break;
+	}
+
+	return r;
+}
+
 static int gunyah_vm_release(struct inode *inode, struct file *filp)
 {
 	struct gunyah_vm *ghvm = filp->private_data;
+	int ret;
+
+	if (ghvm->vm_status == GUNYAH_RM_VM_STATUS_RUNNING)
+		gunyah_vm_stop(ghvm);
+
+	if (ghvm->vm_status != GUNYAH_RM_VM_STATUS_NO_STATE &&
+	    ghvm->vm_status != GUNYAH_RM_VM_STATUS_LOAD &&
+	    ghvm->vm_status != GUNYAH_RM_VM_STATUS_RESET) {
+		ret = gunyah_rm_vm_reset(ghvm->rm, ghvm->vmid);
+		if (ret)
+			dev_err(ghvm->parent, "Failed to reset the vm: %d\n",
+				ret);
+		wait_event(ghvm->vm_status_wait,
+			   ghvm->vm_status == GUNYAH_RM_VM_STATUS_RESET);
+	}
+
+	if (ghvm->vm_status > GUNYAH_RM_VM_STATUS_NO_STATE) {
+		gunyah_rm_notifier_unregister(ghvm->rm, &ghvm->nb);
+
+		ret = gunyah_rm_dealloc_vmid(ghvm->rm, ghvm->vmid);
+		if (ret)
+			dev_warn(ghvm->parent,
+				 "Failed to deallocate vmid: %d\n", ret);
+	}
 
 	gunyah_rm_put(ghvm->rm);
 	kfree(ghvm);
@@ -40,6 +232,8 @@ static int gunyah_vm_release(struct inode *inode, struct file *filp)
 
 static const struct file_operations gunyah_vm_fops = {
 	.owner = THIS_MODULE,
+	.unlocked_ioctl = gunyah_vm_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
 	.release = gunyah_vm_release,
 	.llseek = noop_llseek,
 };
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 434a510e360f..aa058722c5fe 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -8,6 +8,10 @@
 
 #include <linux/device.h>
 #include <linux/gunyah_rsc_mgr.h>
+#include <linux/kref.h>
+#include <linux/notifier.h>
+#include <linux/rwsem.h>
+#include <linux/wait.h>
 
 #include <uapi/linux/gunyah.h>
 
@@ -15,8 +19,15 @@ long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd,
 			     unsigned long arg);
 
 struct gunyah_vm {
+	u16 vmid;
 	struct gunyah_rm *rm;
 	struct device *parent;
+	enum gunyah_rm_vm_auth_mechanism auth;
+
+	struct notifier_block nb;
+	enum gunyah_rm_vm_status vm_status;
+	wait_queue_head_t vm_status_wait;
+	struct rw_semaphore status_lock;
 };
 
 #endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index ac338ec4b85d..31e7f79a6c39 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -20,4 +20,9 @@
  */
 #define GUNYAH_CREATE_VM _IO(GUNYAH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
 
+/*
+ * ioctls for gunyah-vm fds (returned by GUNYAH_CREATE_VM)
+ */
+#define GUNYAH_VM_START		_IO(GUNYAH_IOCTL_TYPE, 0x3)
+
 #endif

-- 
2.43.0