Re: [PATCH v2 1/3] selftests: kvm: s390: Add uc_map_unmap VM test case

On Mon, 2 Sep 2024 13:50:00 +0200 Christoph Schlameuss schlameuss@linux.ibm.com 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 | 121 +++++++++++++++++- 1 file changed, 120 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/s390x/ucontrol_test.c b/tools/testing/selftests/kvm/s390x/ucontrol_test.c index 030c59010fe1..04a0d55af617 100644 --- a/tools/testing/selftests/kvm/s390x/ucontrol_test.c +++ b/tools/testing/selftests/kvm/s390x/ucontrol_test.c @@ -16,7 +16,11 @@ #include <linux/capability.h> #include <linux/sizes.h> +#define PGM_SEGMENT_TRANSLATION 0x10

#define VM_MEM_SIZE (4 * SZ_1M) +#define VM_MEM_EXT_SIZE (2 * SZ_1M) +#define VM_MEM_MAX_M ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M) /* so directly declare capget to check caps without libcap */ int capget(cap_user_header_t header, cap_user_data_t data); @@ -58,6 +62,23 @@ asm("test_gprs_asm:\n" " j 0b\n" ); +/* Test program manipulating memory */ +extern char test_mem_asm[]; +asm("test_mem_asm:\n"

• "xgr %r0, %r0\n"
• "0:\n"
• " ahi %r0,1\n"
• " st %r1,0(%r5,%r6)\n"
• " xgr %r1,%r1\n"
• " l %r1,0(%r5,%r6)\n"
• " ahi %r0,1\n"
• " diag 0,0,0x44\n"
• " j 0b\n"

+);

FIXTURE(uc_kvm) { struct kvm_s390_sie_block *sie_block; @@ -67,6 +88,7 @@ FIXTURE(uc_kvm) uintptr_t base_hva; uintptr_t code_hva; int kvm_run_size;

• vm_paddr_t pgd; void *vm_mem; int vcpu_fd; int kvm_fd;

@@ -116,7 +138,7 @@ FIXTURE_SETUP(uc_kvm) self->base_gpa = 0; self->code_gpa = self->base_gpa + (3 * SZ_1M);

• self->vm_mem = aligned_alloc(SZ_1M, VM_MEM_SIZE);

• self->vm_mem = aligned_alloc(SZ_1M, VM_MEM_MAX_M * SZ_1M); ASSERT_NE(NULL, self->vm_mem) TH_LOG("malloc failed %u", errno); self->base_hva = (uintptr_t)self->vm_mem; self->code_hva = self->base_hva - self->base_gpa + self->code_gpa;

@@ -222,6 +244,36 @@ TEST(uc_cap_hpage) close(kvm_fd); } +/* calculate host virtual addr from guest physical addr */ +static void *gpa2hva(FIXTURE_DATA(uc_kvm) * self, u64 gpa) +{

• return (void *)(self->base_hva - self->base_gpa + gpa);

+}

+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,
  

• };
  

you could use the wrapper here too (see below)

• 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;
  

so this will always return true

• default:

• TEST_FAIL("UNEXPECTED PGM CODE %d", run->s390_ucontrol.pgm_code);
  

• }

+}

/* verify SIEIC exit

• • reset stop requests
• • fail on codes not expected in the test cases

@@ -256,6 +308,12 @@ static bool uc_handle_exit(FIXTURE_DATA(uc_kvm) * self) struct kvm_run *run = self->run; switch (run->exit_reason) {

• case KVM_EXIT_S390_UCONTROL:

• /** check program interruption code
  

•  * handle page fault --> ucas map
  

•  */
  

• uc_handle_exit_ucontrol(self);
  

• break;
  

  case KVM_EXIT_S390_SIEIC: return uc_handle_sieic(self); default:

@@ -287,6 +345,67 @@ static void uc_assert_diag44(FIXTURE_DATA(uc_kvm) * self) TEST_ASSERT_EQ(0x440000, sie_block->ipb); } +TEST_F(uc_kvm, uc_map_unmap) +{

• struct kvm_sync_regs *sync_regs = &self->run->s.regs;
• struct kvm_run *run = self->run;
• int rc;
• /* copy test_mem_asm to code_hva / code_gpa */
• TH_LOG("copy code %p to vm mapped memory %p / %p",

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

• memcpy((void *)self->code_hva, &test_mem_asm, PAGE_SIZE);
• /* DAT disabled + 64 bit mode */
• run->psw_mask = 0x0000000180000000ULL;
• run->psw_addr = self->code_gpa;
• /* set register content for test_mem_asm to access not mapped memory*/
• sync_regs->gprs[1] = 0x55;
• sync_regs->gprs[5] = self->base_gpa;
• sync_regs->gprs[6] = VM_MEM_SIZE;
• run->kvm_dirty_regs |= KVM_SYNC_GPRS;
• /* run and expect to fail with ucontrol pic segment translation */
• ASSERT_EQ(0, uc_run_once(self));
• ASSERT_EQ(1, sync_regs->gprs[0]);
• ASSERT_EQ(KVM_EXIT_S390_UCONTROL, run->exit_reason);
• ASSERT_EQ(PGM_SEGMENT_TRANSLATION, run->s390_ucontrol.pgm_code);
• ASSERT_EQ(self->base_gpa + VM_MEM_SIZE, run->s390_ucontrol.trans_exc_code);
• /* map / make additional memory available */
• struct kvm_s390_ucas_mapping map2 = {

• .user_addr = (u64)gpa2hva(self, self->base_gpa + VM_MEM_SIZE),
  

• .vcpu_addr = self->base_gpa + VM_MEM_SIZE,
  

• .length = VM_MEM_EXT_SIZE,
  

• };
• TH_LOG("ucas map %p %p 0x%llx",

•       (void *)map2.user_addr, (void *)map2.vcpu_addr,
  

map2.length);

• rc = ioctl(self->vcpu_fd, KVM_S390_UCAS_MAP, &map2);

maybe you can put the map/unmap IOCTLs in a wrapper, so that this becomes more readable?

rc = uc_map_ext(self->base_gpa + VM_MEM_SIZE, self->base_gpa +VM_MEM_SIZE);

• ASSERT_EQ(0, rc)

• TH_LOG("ucas map result %d not expected, %s", rc, strerror(errno));
  

• ASSERT_EQ(0, uc_run_once(self));
• ASSERT_EQ(false, uc_handle_exit(self));
• uc_assert_diag44(self);
• /* assert registers and memory are in expected state */
• ASSERT_EQ(2, sync_regs->gprs[0]);
• ASSERT_EQ(0x55, sync_regs->gprs[1]);
• ASSERT_EQ(0x55, *(u32 *)gpa2hva(self, self->base_gpa + VM_MEM_SIZE));
• /* unmap and run loop again */
• TH_LOG("ucas unmap %p %p 0x%llx",

•       (void *)map2.user_addr, (void *)map2.vcpu_addr, map2.length);
  

• rc = ioctl(self->vcpu_fd, KVM_S390_UCAS_UNMAP, &map2);
• ASSERT_EQ(0, rc)

• TH_LOG("ucas unmap result %d not expected, %s", rc, strerror(errno));
  

• ASSERT_EQ(0, uc_run_once(self));
• ASSERT_EQ(3, sync_regs->gprs[0]);
• ASSERT_EQ(KVM_EXIT_S390_UCONTROL, run->exit_reason);
• ASSERT_EQ(PGM_SEGMENT_TRANSLATION, run->s390_ucontrol.pgm_code);
• ASSERT_EQ(true, uc_handle_exit(self));

+}

TEST_F(uc_kvm, uc_gprs) { struct kvm_sync_regs *sync_regs = &self->run->s.regs;