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From:   Sunil Muthuswamy <sunilmut@microsoft.com>
To:     Nuno Das Neves <nunodasneves@linux.microsoft.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     "virtualization@lists.linux-foundation.org" 
        <virtualization@lists.linux-foundation.org>,
        Michael Kelley <mikelley@microsoft.com>,
        "viremana@linux.microsoft.com" <viremana@linux.microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
        vkuznets <vkuznets@redhat.com>,
        Lillian Grassin-Drake <Lillian.GrassinDrake@microsoft.com>,
        KY Srinivasan <kys@microsoft.com>
Subject: RE: [PATCH 03/19] drivers/hv: minimal mshv module (/dev/mshv/)
Thread-Topic: [PATCH 03/19] drivers/hv: minimal mshv module (/dev/mshv/)
Thread-Index: AQHXVBLqkkWi1wc3SES2ayhRv8Vib6sBXHLg
Date:   Thu, 3 Jun 2021 01:28:08 +0000
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References: <1622241819-21155-1-git-send-email-nunodasneves@linux.microsoft.com>
 <1622241819-21155-4-git-send-email-nunodasneves@linux.microsoft.com>
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> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index 66c794d92391..d618b1fab2bb 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -27,4 +27,22 @@ config HYPERV_BALLOON
>  	help
>  	  Select this option to enable Hyper-V Balloon driver.
>=20
> +config HYPERV_ROOT_API

A more suitable place to put this would be under the "VIRTUALIZATION"
config menu option, where we have the "KVM" option today.

> +	tristate "Microsoft Hypervisor root partition interfaces: /dev/mshv"
> +	depends on HYPERV
> +	help
> +	  Provides access to interfaces for managing guest virtual machines
> +	  running under the Microsoft Hypervisor.

These are technically not "root" interfaces. As you say it too, these are
interfaces to manage guest VMs. Calling it "HYPERV_ROOT_API" would
be confusing. Something along the lines of "HYPERV_VMM_API" or
"HYPERV_VM_API" seems more appropriate to me.

> new file mode 100644
> index 000000000000..c68cc84fb983
> --- /dev/null
> +++ b/drivers/hv/mshv_main.c
Why not in /virt/hv or something under /virt?

> +static int mshv_dev_open(struct inode *inode, struct file *filp);
> +static int mshv_dev_release(struct inode *inode, struct file *filp);
> +static long mshv_dev_ioctl(struct file *filp, unsigned int ioctl, unsign=
ed long arg);

Do we need to have both 'mshv' & 'dev' in the name? How about just
calling these 'mshv_xyz'? Like you have for init/exit.

> +
> +static struct miscdevice mshv_dev =3D {
> +	.minor =3D MISC_DYNAMIC_MINOR,
> +	.name =3D "mshv",
> +	.fops =3D &mshv_dev_fops,
> +	.mode =3D 600,
> +};
For the default mode, I think we want to keep it the same as that for 'kvm'=
.

- Sunil