Re: [PATCH v9 11/27] gunyah: vm_mgr: Introduce basic VM Manager

Srinivas Kandagatla
2023-02-02T12:54:38Z

On 20/01/2023 22:46, Elliot Berman wrote:
> Gunyah VM manager is a kernel moduel which exposes an interface to
> Gunyah userspace to load, run, and interact with other Gunyah virtual
> machines. The interface is a character device at /dev/gunyah.
>
> Add a basic VM manager driver. Upcoming patches will add more ioctls
> into this driver.
>
> 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>
> ---
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> drivers/virt/gunyah/Makefile | 2 +-
> drivers/virt/gunyah/rsc_mgr.c | 51 +++++++-
> drivers/virt/gunyah/vm_mgr.c | 117 ++++++++++++++++++
> drivers/virt/gunyah/vm_mgr.h | 20 +++
> include/linux/gunyah_rsc_mgr.h | 3 +
> include/uapi/linux/gunyah.h | 23 ++++
> 7 files changed, 215 insertions(+), 2 deletions(-)
> create mode 100644 drivers/virt/gunyah/vm_mgr.c
> create mode 100644 drivers/virt/gunyah/vm_mgr.h
> create mode 100644 include/uapi/linux/gunyah.h
>
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index eb045fc495a4..8696dc3cdd83 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -137,6 +137,7 @@ Code Seq# Include File Comments
> 'F' DD video/sstfb.h conflict!
> 'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict!
> 'G' 00-0F xen/gntalloc.h, xen/gntdev.h conflict!
> +'G' 00-0f linux/gunyah.h conflict!
> 'H' 00-7F linux/hiddev.h conflict!
> 'H' 00-0F linux/hidraw.h conflict!
> 'H' 01 linux/mei.h conflict!
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index de29769f2f3f..03951cf82023 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -2,5 +2,5 @@
>
> obj-$(CONFIG_GUNYAH) += gunyah.o
>
> -gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o
> +gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o
> obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
> index 382f9943fd31..95f4aa928aaf 100644
> --- a/drivers/virt/gunyah/rsc_mgr.c
> +++ b/drivers/virt/gunyah/rsc_mgr.c
> @@ -16,8 +16,10 @@
> #include <linux/completion.h>
> #include <linux/gunyah_rsc_mgr.h>
> #include <linux/platform_device.h>
> +#include <linux/miscdevice.h>
>
> #include "rsc_mgr.h"
> +#include "vm_mgr.h"
>
> #define RM_RPC_API_VERSION_MASK GENMASK(3, 0)
> #define RM_RPC_HEADER_WORDS_MASK GENMASK(7, 4)
> @@ -105,6 +107,7 @@ struct gh_rm {
> struct kmem_cache *cache;
> struct mutex send_lock;
>
> + struct miscdevice miscdev;
> struct work_struct recv_work;
> };
>
> @@ -526,6 +529,33 @@ int gh_rm_call(struct gh_rm *rm, u32 message_id, void *req_buff, size_t req_buff
> return ret;
> }
>
> +void get_gh_rm(struct gh_rm *rm)
> +{
> + get_device(rm->dev);
> +}
> +EXPORT_SYMBOL_GPL(get_gh_rm);

We have 4/5 different vairants of exported symbols now.

EXPORT_SYMBOL_GPL(gunyah_vm_function_unregister);
EXPORT_SYMBOL_GPL(ghvm_add_resource_ticket);
EXPORT_SYMBOL_GPL(gh_vm_mgr_mmio_write);
EXPORT_SYMBOL_GPL(put_gh_rm);
EXPORT_SYMBOL_GPL(get_gunyah_vm);

I think this needs to be cleaned up for consistency reasons.

> +
> +void put_gh_rm(struct gh_rm *rm)
> +{
> + put_device(rm->dev);
> +}
> +EXPORT_SYMBOL_GPL(put_gh_rm);
> +
> +static long gh_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> +{
> + struct miscdevice *miscdev = filp->private_data;
> + struct gh_rm *rm = container_of(miscdev, struct gh_rm, miscdev);
> +
> + return gh_dev_vm_mgr_ioctl(rm, cmd, arg);
> +}
> +
> +static const struct file_operations gh_dev_fops = {
> + .owner = THIS_MODULE,
> + .unlocked_ioctl = gh_dev_ioctl,
> + .compat_ioctl = compat_ptr_ioctl,
> + .llseek = noop_llseek,
> +};
> +
> static int gh_msgq_platform_probe_direction(struct platform_device *pdev,
> bool tx, int idx, struct gunyah_resource *ghrsc)
> {
> @@ -582,13 +612,32 @@ static int gh_rm_drv_probe(struct platform_device *pdev)
> rm->msgq_client.rx_callback = gh_rm_msgq_rx_data;
> rm->msgq_client.tx_done = gh_rm_msgq_tx_done;
>
> - return gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
> + ret = gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
> + if (ret)
> + goto err_cache;
> +
> + rm->miscdev.name = "gunyah";
> + rm->miscdev.minor = MISC_DYNAMIC_MINOR;
> + rm->miscdev.fops = &gh_dev_fops;
> +
> + ret = misc_register(&rm->miscdev);
> + if (ret)
> + goto err_msgq;
> +
> + return 0;
> +err_msgq:
> + mbox_free_channel(gh_msgq_chan(&rm->msgq));
> + gh_msgq_remove(&rm->msgq);
> +err_cache:
> + kmem_cache_destroy(rm->cache);
> + return ret;
> }
>
> static int gh_rm_drv_remove(struct platform_device *pdev)
> {
> struct gh_rm *rm = platform_get_drvdata(pdev);
>
> + misc_deregister(&rm->miscdev);
> mbox_free_channel(gh_msgq_chan(&rm->msgq));
> gh_msgq_remove(&rm->msgq);
> kmem_cache_destroy(rm->cache);
> diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
> new file mode 100644
> index 000000000000..0864dbd77e28
> --- /dev/null
> +++ b/drivers/virt/gunyah/vm_mgr.c
> @@ -0,0 +1,117 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#define pr_fmt(fmt) "gh_vm_mgr: " fmt
> +
> +#include <linux/anon_inodes.h>
> +#include <linux/file.h>
> +#include <linux/gunyah_rsc_mgr.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +
> +#include <uapi/linux/gunyah.h>
> +
> +#include "vm_mgr.h"
> +
> +static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gh_rm_rpc *rm)
> +{
> + struct gunyah_vm *ghvm;
> + int vmid;
> +
> + vmid = gh_rm_alloc_vmid(rm, 0);
> + if (vmid < 0)
> + return ERR_PTR(vmid);
> +
> + ghvm = kzalloc(sizeof(*ghvm), GFP_KERNEL);
> + if (!ghvm) {
> + gh_rm_dealloc_vmid(rm, vmid);
> + return ghvm;

return ERR_PTR(-ENOMEM);

> + }
> +
> + get_gh_rm(rm);
> +
> + ghvm->vmid = vmid;
> + ghvm->rm = rm;
> +
> + return ghvm;
> +}
> +
> +static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> +{
> + long r;
> +
> + switch (cmd) {
> + default:
> + r = -ENOTTY;
> + break;
> + }

this function looks like dummy, why do we need this in this patch?

> +
> + return r;
> +}
> +
> +static int gh_vm_release(struct inode *inode, struct file *filp)
> +{
> + struct gunyah_vm *ghvm = filp->private_data;
> +
> + put_gh_rm(ghvm->rm);
> + kfree(ghvm);
> + return 0;
> +}
> +
> +static const struct file_operations gh_vm_fops = {
> + .unlocked_ioctl = gh_vm_ioctl,
> + .release = gh_vm_release,
> + .compat_ioctl = compat_ptr_ioctl,
> + .llseek = noop_llseek,
> +};
> +
> +static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
> +{
> + struct gunyah_vm *ghvm;
> + struct file *file;
> + int fd, err;
> +
> + /* arg reserved for future use. */
> + if (arg)
> + return -EINVAL;

Bit confused here, GH_CREATE_VM IOCTL does not take any arguments so why
is this arg reserved for future use. Are you going to change the ABI for
GH_CREATE_VM?

> +
> + ghvm = gunyah_vm_alloc(rm);
> + if (IS_ERR_OR_NULL(ghvm))
> + return PTR_ERR(ghvm) ? : -ENOMEM;
> +
> + fd = get_unused_fd_flags(O_CLOEXEC);
> + if (fd < 0) {
> + err = fd;
> + goto err_destroy_vm;
> + }
> +
> + file = anon_inode_getfile("gunyah-vm", &gh_vm_fops, ghvm, O_RDWR);
> + if (IS_ERR(file)) {
> + err = PTR_ERR(file);
> + goto err_put_fd;
> + }
> +
> + fd_install(fd, file);
> +
> + return fd;
> +
> +err_put_fd:
> + put_unused_fd(fd);
> +err_destroy_vm:
> + kfree(ghvm);
> + return err;
> +}
> +
> +long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg)
> +{
> + switch (cmd) {
> + case GH_CREATE_VM:
> + return gh_dev_ioctl_create_vm(rm, arg);
> + default:
> + return -ENOIOCTLCMD;
> + }
> +}
> +EXPORT_SYMBOL_GPL(gh_dev_vm_mgr_ioctl);
> +
> diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
> new file mode 100644
> index 000000000000..e47f34de7f9e
> --- /dev/null
> +++ b/drivers/virt/gunyah/vm_mgr.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _GH_PRIV_VM_MGR_H
> +#define _GH_PRIV_VM_MGR_H
> +
> +#include <linux/gunyah_rsc_mgr.h>
> +
> +#include <uapi/linux/gunyah.h>
> +
> +long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg);
> +
> +struct gunyah_vm {
> + u16 vmid;
> + struct gh_rm_rpc *rm;
> +};
> +
> +#endif
> diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
> index be0bce5507b1..9a9a037b349a 100644
> --- a/include/linux/gunyah_rsc_mgr.h
> +++ b/include/linux/gunyah_rsc_mgr.h
> @@ -17,6 +17,9 @@
>
> struct gh_rm;
>
> +void get_gh_rm(struct gh_rm *rm);
> +void put_gh_rm(struct gh_rm *rm);
> +
> enum gh_rm_vm_status {
> GH_RM_VM_STATUS_NO_STATE = 0,
> GH_RM_VM_STATUS_INIT = 1,
> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
> new file mode 100644
> index 000000000000..88a40d6e0b96
> --- /dev/null
> +++ b/include/uapi/linux/gunyah.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
> +/*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _UAPI_LINUX_GUNYAH
> +#define _UAPI_LINUX_GUNYAH
> +
> +/*
> + * Userspace interface for /dev/gunyah - gunyah based virtual machine
> + */
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +#define GH_IOCTL_TYPE 'G'
> +
> +/*
> + * ioctls for /dev/gunyah fds:
> + */
> +#define GH_CREATE_VM _IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
> +
> +#endif