Re: [kvm-unit-tests PATCH v1] s390x: cmm: test no-translate bit after reset

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Wed, 15 Nov 2023 09:38:32 +0100
Nico Boehr <nrb@linux.ibm.com> wrote:

> KVM did not properly reset the no-translate bit after reset, see
> https://lore.kernel.org/kvm/20231109123624.37314-1-imbrenda@linux.ibm.com/
> 
> Add a test which performs a load normal reset (includes a subsystem
> reset) and verify that this clears the no-translate bit.
> 
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> ---
>  s390x/cmm.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/s390x/cmm.c b/s390x/cmm.c
> index af852838851e..8f10c107d81b 100644
> --- a/s390x/cmm.c
> +++ b/s390x/cmm.c
> @@ -9,6 +9,7 @@
>   */
>  
>  #include <libcflat.h>
> +#include <bitops.h>
>  #include <asm/asm-offsets.h>
>  #include <asm/interrupt.h>
>  #include <asm/page.h>
> @@ -16,6 +17,8 @@
>  
>  static uint8_t pagebuf[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
>  
> +extern int diag308_load_reset(u64);
> +
>  static void test_params(void)
>  {
>  	report_prefix_push("invalid ORC 8");
> @@ -35,6 +38,26 @@ static void test_priv(void)
>  	report_prefix_pop();
>  }
>  
> +static void test_reset_no_translate(void)
> +{
> +	unsigned long state;
> +	const uint64_t mask_no_translate = BIT(63 - 58);

reverse Christmas tree, please :)

also, maybe it's easier to read with just a numeric constant? i.e. 0x20 


with the Christmas tree fixed (with or without numeric constant):

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Tested-by: Claudio Imbrenda <imbrenda@linux.ibm.com>


> +
> +	report_prefix_push("reset no-translate");
> +	essa(ESSA_SET_STABLE_NODAT, (unsigned long)pagebuf);
> +
> +	state = essa(ESSA_GET_STATE, (unsigned long)pagebuf);
> +	report(state & mask_no_translate, "no-translate bit set before reset");
> +
> +	/* Load normal reset - includes subsystem reset */
> +	diag308_load_reset(1);
> +
> +	state = essa(ESSA_GET_STATE, (unsigned long)pagebuf);
> +	report(!(state & mask_no_translate), "no-translate bit unset after reset");
> +
> +	report_prefix_pop();
> +}
> +
>  int main(void)
>  {
>  	bool has_essa = check_essa_available();
> @@ -47,6 +70,7 @@ int main(void)
>  
>  	test_priv();
>  	test_params();
> +	test_reset_no_translate();
>  done:
>  	report_prefix_pop();
>  	return report_summary();