Re: [kvm-unit-tests PATCH v3 5/6] lib: s390x: Enable reusability of VMs that were in PV mode

[Steffen Eiden <seiden@linux.ibm.com>]

On 10/21/22 08:39, Janosch Frank wrote:
> Convert the sblk to non-PV when the PV guest is destroyed.
> 
> Early return in uv_init() instead of running into the assert. This is
> necessary since snippet_pv_init() will always call uv_init().
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
> ---
>   lib/s390x/uv.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/s390x/uv.c b/lib/s390x/uv.c
> index b2a43424..383271a5 100644
> --- a/lib/s390x/uv.c
> +++ b/lib/s390x/uv.c
> @@ -76,7 +76,8 @@ void uv_init(void)
>   	int cc;
>   
>   	/* Let's not do this twice */
> -	assert(!initialized);
> +	if (initialized)
> +		return;
>   	/* Query is done on initialization but let's check anyway */
>   	assert(uvcb_qui.header.rc == 1 || uvcb_qui.header.rc == 0x100);
>   
> @@ -188,6 +189,14 @@ void uv_destroy_guest(struct vm *vm)
>   	free_pages(vm->uv.conf_var_stor);
>   
>   	free_pages((void *)(vm->uv.asce & PAGE_MASK));
> +	memset(&vm->uv, 0, sizeof(vm->uv));
> +
> +	/* Convert the sblk back to non-PV */
> +	vm->save_area.guest.asce = stctg(1);
> +	vm->sblk->sdf = 0;
> +	vm->sblk->sidad = 0;
> +	vm->sblk->pv_handle_cpu = 0;
> +	vm->sblk->pv_handle_config = 0;
>   }
>   
>   int uv_unpack(struct vm *vm, uint64_t addr, uint64_t len, uint64_t tweak)