Re: [PATCH 1/3] selftests: kvm: s390: Add uc_map_unmap VM test case

Janosch Frank
2024-08-23T08:02:51Z

On 8/19/24 6:03 PM, Christoph Schlameuss wrote:
> On Fri Aug 16, 2024 at 4:29 PM CEST, Janosch Frank wrote:
>> On 8/15/24 5:45 PM, Christoph Schlameuss wrote:
>>> Add a test case verifying basic running and interaction of ucontrol VMs.
>>> Fill the segment and page tables for allocated memory and map memory on
>>> first access.
>>>
>>> * uc_map_unmap
>>> Store and load data to mapped and unmapped memory and use pic segment
>>> translation handling to map memory on access.
>>>
>>> Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
>>> ---
>>> .../selftests/kvm/s390x/ucontrol_test.c | 120 +++++++++++++++++-
>>> 1 file changed, 119 insertions(+), 1 deletion(-)
>>>
>>
>>> +static void uc_handle_exit_ucontrol(FIXTURE_DATA(uc_kvm) * self)
>>> +{
>>> + struct kvm_run *run = self->run;
>>> +
>>> + TEST_ASSERT_EQ(KVM_EXIT_S390_UCONTROL, run->exit_reason);
>>> + switch (run->s390_ucontrol.pgm_code) {
>>> + case PGM_SEGMENT_TRANSLATION:
>>> + pr_info("ucontrol pic segment translation 0x%llx\n",
>>> + run->s390_ucontrol.trans_exc_code);
>>> + /* map / make additional memory available */
>>> + struct kvm_s390_ucas_mapping map2 = {
>>> + .user_addr = (u64)gpa2hva(self, run->s390_ucontrol.trans_exc_code),
>>> + .vcpu_addr = run->s390_ucontrol.trans_exc_code,
>>> + .length = VM_MEM_EXT_SIZE,
>>> + };
>>> + pr_info("ucas map %p %p 0x%llx\n",
>>> + (void *)map2.user_addr, (void *)map2.vcpu_addr, map2.length);
>>> + TEST_ASSERT_EQ(0, ioctl(self->vcpu_fd, KVM_S390_UCAS_MAP, &map2));
>>> + break;
>>
>> Why is this necessary if you fix up the mapping in the test?
>>
>
> This is also used within the uc_skey test to make sure the remap does
> work after the unmap.

Maybe I'm blind because I'm still recovering but where exactly?