Re: [PATCH v2 2/3] selftests: kvm: s390: Add uc_skey VM test case

On Thu Sep 12, 2024 at 10:15 AM CEST, Claudio Imbrenda wrote:

On Mon, 2 Sep 2024 13:50:01 +0200 Christoph Schlameuss schlameuss@linux.ibm.com wrote:

...

Add a test case manipulating s390 storage keys from within the ucontrol VM.

Signed-off-by: Christoph Schlameuss schlameuss@linux.ibm.com

.../selftests/kvm/s390x/ucontrol_test.c | 89 ++++++++++++++++++- 1 file changed, 88 insertions(+), 1 deletion(-)

[...]

...

+TEST_F(uc_kvm, uc_skey) +{

• u64 test_vaddr = VM_MEM_SIZE - (SZ_1M / 2);
• struct kvm_sync_regs *sync_regs = &self->run->s.regs;
• struct kvm_run *run = self->run;
• u8 skeyvalue = 0x34;
• /* copy test_skey_asm to code_hva / code_gpa */
• TH_LOG("copy code %p to vm mapped memory %p / %p",

•       &test_skey_asm, (void *)self->code_hva, (void *)self->code_gpa);
  

• memcpy((void *)self->code_hva, &test_skey_asm, PAGE_SIZE);
• /* set register content for test_skey_asm to access not mapped memory */
• sync_regs->gprs[1] = skeyvalue;
• sync_regs->gprs[5] = self->base_gpa;
• sync_regs->gprs[6] = test_vaddr;
• run->kvm_dirty_regs |= KVM_SYNC_GPRS;
• /* DAT disabled + 64 bit mode */
• run->psw_mask = 0x0000000180000000ULL;
• run->psw_addr = self->code_gpa;
• ASSERT_EQ(0, uc_run_once(self));
• ASSERT_EQ(false, uc_handle_exit(self));

this should be true, since KSS will be triggered

Good find. Yes, as this is the assertion does actually fail here. Will fix that in the next version.

...

• ASSERT_EQ(1, sync_regs->gprs[0]);
• /* ISKE */
• ASSERT_EQ(0, uc_run_once(self));
• ASSERT_EQ(false, uc_handle_exit(self));
• ASSERT_EQ(2, sync_regs->gprs[0]);
• /* assert initial skey (ACC = 0, R & C = 1) */
• ASSERT_EQ(0x06, sync_regs->gprs[1]);
• uc_assert_diag44(self);

[...]