Reserve ioctl number in userpsace-api/ioctl/ioctl-number.rst Introduce MSHV_CHECK_EXTENSION ioctl. Introduce documentation for /dev/mshv in Documentation/virt/mshv Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx> --- .../userspace-api/ioctl/ioctl-number.rst | 2 + Documentation/virt/mshv/api.rst | 60 +++++++++++++++++++ drivers/hv/mshv_main.c | 23 +++++++ include/linux/mshv.h | 11 ++++ include/uapi/linux/mshv.h | 20 +++++++ 5 files changed, 116 insertions(+) create mode 100644 Documentation/virt/mshv/api.rst create mode 100644 include/linux/mshv.h create mode 100644 include/uapi/linux/mshv.h diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 9bfc2b510c64..585d9cc42a5a 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -350,6 +350,8 @@ Code Seq# Include File Comments 0xB6 all linux/fpga-dfl.h 0xB7 all uapi/linux/remoteproc_cdev.h <mailto:linux-remoteproc@xxxxxxxxxxxxxxx> 0xB7 all uapi/linux/nsfs.h <mailto:Andrei Vagin <avagin@xxxxxxxxxx>> +0xB8 all uapi/linux/mshv.h Microsoft Hypervisor root partition APIs + <mailto:linux-hyperv@xxxxxxxxxxxxxxx> 0xC0 00-0F linux/usb/iowarrior.h 0xCA 00-0F uapi/misc/cxl.h 0xCA 10-2F uapi/misc/ocxl.h diff --git a/Documentation/virt/mshv/api.rst b/Documentation/virt/mshv/api.rst new file mode 100644 index 000000000000..75c5e073ecc0 --- /dev/null +++ b/Documentation/virt/mshv/api.rst @@ -0,0 +1,60 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================================== +Microsoft Hypervisor Root Partition API Documentation +===================================================== + +1. Overview +=========== + +This document describes APIs for creating and managing guest virtual machines +when running Linux as the root partition on the Microsoft Hypervisor. + +Note that this API is not yet stable! + +2. Glossary/Terms +================= + +hv +-- +Short for Hyper-V. This name is used in the kernel to describe interfaces to +the Microsoft Hypervisor. + +mshv +---- +Short for Microsoft Hypervisor. This is the name of the userland API module +described in this document. + +Partition +--------- +A virtual machine running on the Microsoft Hypervisor. + +Root Partition +-------------- +The partition that is created and assumes control when the machine boots. The +root partition can use mshv APIs to create guest partitions. + +3. API description +================== + +The module is named mshv and can be configured with CONFIG_HYPERV_ROOT_API. + +Mshv is file descriptor-based, following a similar pattern to KVM. + +To get a handle to the mshv driver, use open("/dev/mshv"). + +3.1 MSHV_CHECK_EXTENSION +------------------------ +:Type: /dev/mshv ioctl +:Parameters: pointer to a u32 +:Returns: 0 if extension unsupported, positive number if supported + +This ioctl takes a single argument corresponding to an API extension to check +support for. + +If the extension is supported, MSHV_CHECK_EXTENSION will return a positive +number. If not, it will return 0. + +The first extension that can be checked is MSHV_CAP_CORE_API_STABLE. This +will be supported when the core API is stable. + diff --git a/drivers/hv/mshv_main.c b/drivers/hv/mshv_main.c index c68cc84fb983..3342ea5bbd1d 100644 --- a/drivers/hv/mshv_main.c +++ b/drivers/hv/mshv_main.c @@ -11,6 +11,8 @@ #include <linux/module.h> #include <linux/fs.h> #include <linux/miscdevice.h> +#include <linux/slab.h> +#include <linux/mshv.h> MODULE_AUTHOR("Microsoft"); MODULE_LICENSE("GPL"); @@ -34,9 +36,30 @@ static struct miscdevice mshv_dev = { .mode = 600, }; +static long +mshv_ioctl_check_extension(void __user *user_arg) +{ + u32 arg; + + if (copy_from_user(&arg, user_arg, sizeof(arg))) + return -EFAULT; + + switch (arg) { + case MSHV_CAP_CORE_API_STABLE: + return 0; + } + + return -ENOTSUPP; +} + static long mshv_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { + switch (ioctl) { + case MSHV_CHECK_EXTENSION: + return mshv_ioctl_check_extension((void __user *)arg); + } + return -ENOTTY; } diff --git a/include/linux/mshv.h b/include/linux/mshv.h new file mode 100644 index 000000000000..a0982fe2c0b8 --- /dev/null +++ b/include/linux/mshv.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _LINUX_MSHV_H +#define _LINUX_MSHV_H + +/* + * Microsoft Hypervisor root partition driver for /dev/mshv + */ + +#include <uapi/linux/mshv.h> + +#endif diff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h new file mode 100644 index 000000000000..3b84e3ea97be --- /dev/null +++ b/include/uapi/linux/mshv.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_LINUX_MSHV_H +#define _UAPI_LINUX_MSHV_H + +/* + * Userspace interface for /dev/mshv + * Microsoft Hypervisor root partition APIs + * NOTE: This API is not yet stable! + */ + +#include <linux/types.h> + +#define MSHV_CAP_CORE_API_STABLE 0x0 + +#define MSHV_IOCTL 0xB8 + +/* mshv device */ +#define MSHV_CHECK_EXTENSION _IOW(MSHV_IOCTL, 0x00, __u32) + +#endif -- 2.25.1
