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Date:   Sun, 27 Sep 2020 12:45:38 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     shuo.a.liu@intel.com
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Yu Wang <yu1.wang@intel.com>,
        Reinette Chatre <reinette.chatre@intel.com>,
        Zhi Wang <zhi.a.wang@intel.com>,
        Zhenyu Wang <zhenyuw@linux.intel.com>
Subject: Re: [PATCH v4 06/17] virt: acrn: Introduce VM management interfaces
Message-ID: <20200927104538.GD88650@kroah.com>
References: <20200922114311.38804-1-shuo.a.liu@intel.com>
 <20200922114311.38804-7-shuo.a.liu@intel.com>
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On Tue, Sep 22, 2020 at 07:43:00PM +0800, shuo.a.liu@intel.com wrote:
> From: Shuo Liu <shuo.a.liu@intel.com>
> 
> The VM management interfaces expose several VM operations to ACRN
> userspace via ioctls. For example, creating VM, starting VM, destroying
> VM and so on.
> 
> The ACRN Hypervisor needs to exchange data with the ACRN userspace
> during the VM operations. HSM provides VM operation ioctls to the ACRN
> userspace and communicates with the ACRN Hypervisor for VM operations
> via hypercalls.
> 
> HSM maintains a list of User VM. Each User VM will be bound to an
> existing file descriptor of /dev/acrn_hsm. The User VM will be
> destroyed when the file descriptor is closed.
> 
> Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
> Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
> Cc: Zhi Wang <zhi.a.wang@intel.com>
> Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
> Cc: Yu Wang <yu1.wang@intel.com>
> Cc: Reinette Chatre <reinette.chatre@intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  .../userspace-api/ioctl/ioctl-number.rst      |  1 +
>  MAINTAINERS                                   |  1 +
>  drivers/virt/acrn/Makefile                    |  2 +-
>  drivers/virt/acrn/acrn_drv.h                  | 23 +++++-
>  drivers/virt/acrn/hsm.c                       | 73 ++++++++++++++++-
>  drivers/virt/acrn/hypercall.h                 | 78 +++++++++++++++++++
>  drivers/virt/acrn/vm.c                        | 71 +++++++++++++++++
>  include/uapi/linux/acrn.h                     | 56 +++++++++++++
>  8 files changed, 301 insertions(+), 4 deletions(-)
>  create mode 100644 drivers/virt/acrn/hypercall.h
>  create mode 100644 drivers/virt/acrn/vm.c
>  create mode 100644 include/uapi/linux/acrn.h
> 
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 2a198838fca9..ac60efedb104 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -319,6 +319,7 @@ Code  Seq#    Include File                                           Comments
>  0xA0  all    linux/sdp/sdp.h                                         Industrial Device Project
>                                                                       <mailto:kenji@bitgate.com>
>  0xA1  0      linux/vtpm_proxy.h                                      TPM Emulator Proxy Driver
> +0xA2  all    uapi/linux/acrn.h                                       ACRN hypervisor
>  0xA3  80-8F                                                          Port ACL  in development:
>                                                                       <mailto:tlewis@mindspring.com>
>  0xA3  90-9F  linux/dtlk.h
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3030d0e93d02..d4c1ef303c2d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -443,6 +443,7 @@ S:	Supported
>  W:	https://projectacrn.org
>  F:	Documentation/virt/acrn/
>  F:	drivers/virt/acrn/
> +F:	include/uapi/linux/acrn.h
>  
>  AD1889 ALSA SOUND DRIVER
>  L:	linux-parisc@vger.kernel.org
> diff --git a/drivers/virt/acrn/Makefile b/drivers/virt/acrn/Makefile
> index 6920ed798aaf..cf8b4ed5e74e 100644
> --- a/drivers/virt/acrn/Makefile
> +++ b/drivers/virt/acrn/Makefile
> @@ -1,3 +1,3 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_ACRN_HSM)	:= acrn.o
> -acrn-y := hsm.o
> +acrn-y := hsm.o vm.o
> diff --git a/drivers/virt/acrn/acrn_drv.h b/drivers/virt/acrn/acrn_drv.h
> index 29eedd696327..72d92b60d944 100644
> --- a/drivers/virt/acrn/acrn_drv.h
> +++ b/drivers/virt/acrn/acrn_drv.h
> @@ -3,16 +3,37 @@
>  #ifndef __ACRN_HSM_DRV_H
>  #define __ACRN_HSM_DRV_H
>  
> +#include <linux/acrn.h>
> +#include <linux/dev_printk.h>
> +#include <linux/miscdevice.h>
>  #include <linux/types.h>
>  
> +#include "hypercall.h"
> +
> +extern struct miscdevice acrn_dev;

Who else needs to get to this structure in your driver?

> +
>  #define ACRN_INVALID_VMID (0xffffU)
>  
> +#define ACRN_VM_FLAG_DESTROYED		0U
> +extern struct list_head acrn_vm_list;
> +extern rwlock_t acrn_vm_list_lock;
>  /**
>   * struct acrn_vm - Properties of ACRN User VM.
> + * @list:	Entry within global list of all VMs
>   * @vmid:	User VM ID
> + * @vcpu_num:	Number of virtual CPUs in the VM
> + * @flags:	Flags (ACRN_VM_FLAG_*) of the VM. This is VM flag management
> + *		in HSM which is different from the &acrn_vm_creation.vm_flag.
>   */
>  struct acrn_vm {
> -	u16	vmid;
> +	struct list_head	list;
> +	u16			vmid;
> +	int			vcpu_num;
> +	unsigned long		flags;
>  };
>  
> +struct acrn_vm *acrn_vm_create(struct acrn_vm *vm,
> +			       struct acrn_vm_creation *vm_param);
> +int acrn_vm_destroy(struct acrn_vm *vm);
> +
>  #endif /* __ACRN_HSM_DRV_H */
> diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
> index 28a3052ffa55..f3e6467b8723 100644
> --- a/drivers/virt/acrn/hsm.c
> +++ b/drivers/virt/acrn/hsm.c
> @@ -9,7 +9,6 @@
>   *	Yakui Zhao <yakui.zhao@intel.com>
>   */
>  
> -#include <linux/miscdevice.h>
>  #include <linux/mm.h>
>  #include <linux/module.h>
>  #include <linux/slab.h>
> @@ -38,10 +37,79 @@ static int acrn_dev_open(struct inode *inode, struct file *filp)
>  	return 0;
>  }
>  
> +/*
> + * HSM relies on hypercall layer of the ACRN hypervisor to do the
> + * sanity check against the input parameters.
> + */
> +static long acrn_dev_ioctl(struct file *filp, unsigned int cmd,
> +			   unsigned long ioctl_param)
> +{
> +	struct acrn_vm *vm = filp->private_data;
> +	struct acrn_vm_creation *vm_param;
> +	int ret = 0;
> +
> +	if (vm->vmid == ACRN_INVALID_VMID && cmd != ACRN_IOCTL_CREATE_VM) {
> +		dev_dbg(acrn_dev.this_device,
> +			"ioctl 0x%x: Invalid VM state!\n", cmd);
> +		return -EINVAL;
> +	}
> +
> +	switch (cmd) {
> +	case ACRN_IOCTL_CREATE_VM:
> +		vm_param = memdup_user((void __user *)ioctl_param,
> +				       sizeof(struct acrn_vm_creation));
> +		if (IS_ERR(vm_param))
> +			return PTR_ERR(vm_param);
> +
> +		vm = acrn_vm_create(vm, vm_param);
> +		if (!vm) {
> +			ret = -EINVAL;
> +			kfree(vm_param);
> +			break;
> +		}
> +
> +		if (copy_to_user((void __user *)ioctl_param, vm_param,
> +				 sizeof(struct acrn_vm_creation))) {
> +			acrn_vm_destroy(vm);
> +			ret = -EFAULT;
> +		}
> +
> +		kfree(vm_param);
> +		break;
> +	case ACRN_IOCTL_START_VM:
> +		ret = hcall_start_vm(vm->vmid);
> +		if (ret < 0)
> +			dev_err(acrn_dev.this_device,
> +				"Failed to start VM %u!\n", vm->vmid);
> +		break;
> +	case ACRN_IOCTL_PAUSE_VM:
> +		ret = hcall_pause_vm(vm->vmid);
> +		if (ret < 0)
> +			dev_err(acrn_dev.this_device,
> +				"Failed to pause VM %u!\n", vm->vmid);
> +		break;
> +	case ACRN_IOCTL_RESET_VM:
> +		ret = hcall_reset_vm(vm->vmid);
> +		if (ret < 0)
> +			dev_err(acrn_dev.this_device,
> +				"Failed to restart VM %u!\n", vm->vmid);
> +		break;
> +	case ACRN_IOCTL_DESTROY_VM:
> +		ret = acrn_vm_destroy(vm);
> +		break;
> +	default:
> +		dev_warn(acrn_dev.this_device, "Unknown IOCTL 0x%x!\n", cmd);

Do not let userspace spam kernel logs with invalid stuff, that's a sure
way to cause a DoS.

thanks,

greg k-h