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Date: Mon, 15 Apr 2024 15:48:34 +0100
From: Simon Horman <horms@kernel.org>
To: Yi-De Wu <yi-de.wu@mediatek.com>
Cc: Yingshiuan Pan <yingshiuan.pan@mediatek.com>,
	Ze-Yu Wang <ze-yu.wang@mediatek.com>, Rob Herring <robh@kernel.org>,
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	PeiLun Suei <peilun.suei@mediatek.com>,
	Liju Chen <liju-clr.chen@mediatek.com>,
	Willix Yeh <chi-shen.yeh@mediatek.com>,
	Kevenny Hsieh <kevenny.hsieh@mediatek.com>
Subject: Re: [PATCH v10 06/21] virt: geniezone: Add set_user_memory_region
 for vm
Message-ID: <20240415144834.GC2320920@kernel.org>
References: <20240412065718.29105-1-yi-de.wu@mediatek.com>
 <20240412065718.29105-7-yi-de.wu@mediatek.com>
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In-Reply-To: <20240412065718.29105-7-yi-de.wu@mediatek.com>

On Fri, Apr 12, 2024 at 02:57:03PM +0800, Yi-De Wu wrote:
> From: "Yingshiuan Pan" <yingshiuan.pan@mediatek.com>
> 
> Direct use of physical memory from VMs is forbidden and designed to be
> dictated to the privilege models managed by GenieZone hypervisor for
> security reason. With the help of gzvm-ko, the hypervisor would be able
> to manipulate memory as objects. And the memory management is highly
> integrated with ARM 2-stage translation tables to convert VA to IPA to
> PA under proper security measures required by protected VMs.
> 
> Signed-off-by: Yingshiuan Pan <yingshiuan.pan@mediatek.com>
> Signed-off-by: Jerry Wang <ze-yu.wang@mediatek.com>
> Signed-off-by: Liju Chen <liju-clr.chen@mediatek.com>
> Signed-off-by: Yi-De Wu <yi-de.wu@mediatek.com>

..

> diff --git a/drivers/virt/geniezone/gzvm_vm.c b/drivers/virt/geniezone/gzvm_vm.c

..

> +/* gzvm_vm_ioctl() - Ioctl handler of VM FD */
> +static long gzvm_vm_ioctl(struct file *filp, unsigned int ioctl,
> +			  unsigned long arg)
> +{
> +	long ret;
> +	void __user *argp = (void __user *)arg;
> +	struct gzvm *gzvm = filp->private_data;
> +
> +	switch (ioctl) {
> +	case GZVM_SET_USER_MEMORY_REGION: {
> +		struct gzvm_userspace_memory_region userspace_mem;
> +
> +		if (copy_from_user(&userspace_mem, argp, sizeof(userspace_mem)))
> +			return -EFAULT;
> +
> +		ret = gzvm_vm_ioctl_set_memory_region(gzvm, &userspace_mem);
> +		break;
> +	}
> +	default:
> +		ret = -ENOTTY;
> +	}
> +out:

nit: the out label as added here, but it does not seem to be used
     (until [PATCH v10 11/21] virt: geniezone: Add irqfd support).

     Although it probably isn't hurting anything - other than automated
     testing - it would be best to add as part of a patch that uses it.

Flagged by gcc-13 and clang-18 W=1 builds.

> +	return ret;
> +}
> +
>  static void gzvm_destroy_vm(struct gzvm *gzvm)
>  {
>  	pr_debug("VM-%u is going to be destroyed\n", gzvm->vm_id);

..