On Fri, Apr 12, 2024 at 02:57:12PM +0800, Yi-De Wu wrote:
> From: "Yingshiuan Pan" <yingshiuan.pan@xxxxxxxxxxxx>
>
> This page fault handler helps GenieZone hypervisor to do demand paging.
> On a lower level translation fault, GenieZone hypervisor will first
> check the fault GPA (guest physical address or IPA in ARM) is valid
> e.g. within the registered memory region, then it will setup the
> vcpu_run->exit_reason with necessary information for returning to
> gzvm driver.
>
> With the fault information, the gzvm driver looks up the physical
> address and call the MT_HVC_GZVM_MAP_GUEST to request the hypervisor
> maps the found PA to the fault GPA (IPA).
>
> There is one exception, for protected vm, we will populate full VM's
> memory region in advance in order to improve performance.
>
> Signed-off-by: Yingshiuan Pan <yingshiuan.pan@xxxxxxxxxxxx>
> Signed-off-by: Jerry Wang <ze-yu.wang@xxxxxxxxxxxx>
> Signed-off-by: kevenny hsieh <kevenny.hsieh@xxxxxxxxxxxx>
> Signed-off-by: Liju Chen <liju-clr.chen@xxxxxxxxxxxx>
> Signed-off-by: Yi-De Wu <yi-de.wu@xxxxxxxxxxxx>
...
> diff --git a/drivers/virt/geniezone/gzvm_exception.c b/drivers/virt/geniezone/gzvm_exception.c
> new file mode 100644
> index 000000000000..475bc15b0689
> --- /dev/null
> +++ b/drivers/virt/geniezone/gzvm_exception.c
> @@ -0,0 +1,39 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2023 MediaTek Inc.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/soc/mediatek/gzvm_drv.h>
> +
> +/**
> + * gzvm_handle_guest_exception() - Handle guest exception
> + * @vcpu: Pointer to struct gzvm_vcpu_run in userspace
> + * Return:
> + * * true - This exception has been processed, no need to back to VMM.
> + * * false - This exception has not been processed, require userspace.
> + */
> +bool gzvm_handle_guest_exception(struct gzvm_vcpu *vcpu)
Hi Yi-De Wu,
The return type is bool, however the function actually
returns either a bool or signed int.
I think that either:
1. The return type should be changed to int,
and returning true and false should be updated.
2. The function should always return true or false.
Flagged by Smatch.
> +{
> + int ret;
> +
> + for (int i = 0; i < ARRAY_SIZE(vcpu->run->exception.reserved); i++) {
> + if (vcpu->run->exception.reserved[i])
> + return -EINVAL;
> + }
> +
> + switch (vcpu->run->exception.exception) {
> + case GZVM_EXCEPTION_PAGE_FAULT:
> + ret = gzvm_handle_page_fault(vcpu);
> + break;
> + case GZVM_EXCEPTION_UNKNOWN:
> + fallthrough;
> + default:
> + ret = -EFAULT;
> + }
> +
> + if (!ret)
> + return true;
> + else
> + return false;
> +}
...
