On 18.09.19 13:24, Alex Bennée wrote:
>
> David Hildenbrand <da...@redhat.com> writes:
>
>> On 18.09.19 11:47, Alex Bennée wrote:
>>>
>>> David Hildenbrand <da...@redhat.com> writes:
>>>
>>>> Let's add the simple test based on the example from the PoP.
>>>>
>>>> Signed-off-by: David Hildenbrand <da...@redhat.com>
>>>> ---
>>>> tests/tcg/s390x/Makefile.target | 1 +
>>>> tests/tcg/s390x/mvo.c | 25 +++++++++++++++++++++++++
>>>> 2 files changed, 26 insertions(+)
>>>> create mode 100644 tests/tcg/s390x/mvo.c
>>>>
>>>> diff --git a/tests/tcg/s390x/Makefile.target
>>>> b/tests/tcg/s390x/Makefile.target
>>>> index 151dc075aa..6a3bfa8b29 100644
>>>> --- a/tests/tcg/s390x/Makefile.target
>>>> +++ b/tests/tcg/s390x/Makefile.target
>>>> @@ -6,3 +6,4 @@ TESTS+=ipm
>>>> TESTS+=exrl-trt
>>>> TESTS+=exrl-trtr
>>>> TESTS+=pack
>>>> +TESTS+=mvo
>>>> diff --git a/tests/tcg/s390x/mvo.c b/tests/tcg/s390x/mvo.c
>>>> new file mode 100644
>>>> index 0000000000..5546fe2a97
>>>> --- /dev/null
>>>> +++ b/tests/tcg/s390x/mvo.c
>>>> @@ -0,0 +1,25 @@
>>>> +#include <stdint.h>
>>>> +#include <stdio.h>
>>>> +
>>>> +int main(void)
>>>> +{
>>>> + uint8_t dest[6] = {0xff, 0x77, 0x88, 0x99, 0x0c, 0xff};
>>>> + uint8_t src[5] = {0xee, 0x12, 0x34, 0x56, 0xee};
>>>> + uint8_t expected[6] = {0xff, 0x01, 0x23, 0x45, 0x6c, 0xff};
>>>> + int i;
>>>> +
>>>> + asm volatile (
>>>> + " mvo 0(4,%[dest]),0(3,%[src])\n"
>>>> + :
>>>> + : [dest] "d" (dest + 1),
>>>> + [src] "d" (src + 1)
>>>> + : "memory");
>>>> +
>>>> + for (i = 0; i < sizeof(expected); i++) {
>>>> + if (dest[i] != expected[i]) {
>>>> + fprintf(stderr, "bad data\n");
>>>> + return 1;
>>>> + }
>>>> + }
>>>> + return 0;
>>>> +}
>>>
>>> Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
>>>
>>> but...
>>>
>>> can this test be expanded to check the page cross cases that caused you
>>> so much trouble to track down?
>>
>> I might add a MVC test that tries to reproduce this. But with
>> speculative page faults and things like that it might not be very easy
>> to reproduce. However, I can give it a try.
>
> I may not be fully understanding the correct behaviour but wouldn't the
> test be:
>
> * map two page's worth of address space
> * mprot(!write) the top page
> * attempt mvc based copy to mmap region (say p0+(PAGE_SIZE>>1) to
> p1+(PAGE_SIZE>>1))
> * catch the fault
> * check the bottom page wasn't written to
No, you are absolutely right, with memmap/mprot hackery + signal handler
this can be tested just fine. I'll craft something for the MVC instruction!
Thanks!
--
Thanks,
David / dhildenb
