[PATCH v2 07/10] selftests: kvm: s390: Add uc_map_unmap VM test case

Christoph Schlameuss
2024-07-23T09:32:11Z

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 | 171 +++++++++++++++++-
1 file changed, 170 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/s390x/ucontrol_test.c b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
index c98d5a3a315b..a39c560ba42e 100644
--- a/tools/testing/selftests/kvm/s390x/ucontrol_test.c
+++ b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
@@ -18,7 +18,13 @@

#define SYS_ADMIN_CAP 0x200000

+#define UC_PIC_SEGMENT_TRANSLATION 0x10
+
#define VM_MEM_SIZE (4 * SZ_1M)
+#define VM_MEM_EXT_SIZE (2 * SZ_1M)
+#define VM_MEM_MAX (VM_MEM_SIZE + VM_MEM_EXT_SIZE)
+
+#define PAGES_PER_SEGMENT 4

/* so directly declare capget to check caps without libcap */
int capget(cap_user_header_t header, cap_user_data_t data);
@@ -60,6 +66,23 @@ asm("test_gprs_pgm:\n"
" j 0b\n"
);

+/* Test program manipulating memory */
+extern char test_mem_pgm[];
+asm("test_mem_pgm:\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;
@@ -69,6 +92,7 @@ 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;
@@ -118,7 +142,7 @@ 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_SIZE + VM_MEM_EXT_SIZE);
ASSERT_NE(NULL, self->vm_mem) TH_LOG("malloc failed %u", errno);
self->base_hva = (uintptr_t)self->vm_mem + SZ_1M;
self->code_hva = self->base_hva - self->base_gpa + self->code_gpa;
@@ -222,6 +246,75 @@ 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);
+}
+
+/* initialize segment and page tables for uc_kvm tests */
+static void init_st_pt(FIXTURE_DATA(uc_kvm) * self)
+{
+ struct kvm_sync_regs *sync_regs = &self->run->s.regs;
+ struct kvm_run *run = self->run;
+ void *se_addr;
+ int si, pi;
+ u64 *phd;
+
+ self->pgd = self->base_gpa + SZ_1M; /* set PASCE addr */
+ phd = gpa2hva(self, self->pgd);
+ memset(phd, 0xff, PAGES_PER_SEGMENT * PAGE_SIZE);
+
+ for (si = 0; si < ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M); si++) {
+ /* create ste */
+ phd[si] = (self->pgd
+ + (PAGES_PER_SEGMENT * PAGE_SIZE
+ * ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M))
+ + (PAGES_PER_SEGMENT * PAGE_SIZE * si)) & ~0x7fful;
+ se_addr = gpa2hva(self, phd[si]);
+ memset(se_addr, 0xff, PAGES_PER_SEGMENT * PAGE_SIZE);
+ for (pi = 0; pi < (SZ_1M / PAGE_SIZE); pi++) {
+ /* create pte */
+ ((u64 *)se_addr)[pi] = (self->base_gpa
+ + (si * SZ_1M) + (pi * PAGE_SIZE)) & ~0xffful;
+ }
+ }
+ pr_debug("segment table entry %p (0x%lx) --> %p\n",
+ phd, phd[0], gpa2hva(self, (phd[0] & ~0x7fful)));
+ print_hex_bytes("st", (u64)phd, 64);
+ print_hex_bytes("pt", (u64)gpa2hva(self, phd[0]), 128);
+ print_hex_bytes("pt+", (u64)
+ gpa2hva(self, phd[0] + (PAGES_PER_SEGMENT * PAGE_SIZE
+ * ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M)) - 0x64), 128);
+
+ sync_regs->crs[1] = self->pgd | 0x3; /* PASCE TT=00 for segment table */
+ run->kvm_dirty_regs |= KVM_SYNC_CRS;
+}
+
+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 UC_PIC_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;
+ 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
@@ -245,7 +338,11 @@ static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
break;
case ICPT_INST:
/* end execution in caller on intercepted instruction */
+ pr_info("sie instruction interception\n");
return false;
+ case ICPT_OPEREXC:
+ /* operation exception */
+ TEST_FAIL("sie exception on %.4x%.8x", sie_block->ipa, sie_block->ipb);
default:
TEST_FAIL("UNEXPECTED SIEIC CODE %d", run->s390_sieic.icptcode);
}
@@ -258,6 +355,11 @@ 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:
@@ -289,6 +391,73 @@ 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_s390_sie_block *sie_block = self->sie_block;
+ struct kvm_run *run = self->run;
+ int rc;
+
+ init_st_pt(self);
+
+ /* copy test_mem_pgm to code_hva / code_gpa */
+ TH_LOG("copy code %p to vm mapped memory %p / %p",
+ &test_mem_pgm, (void *)self->code_hva, (void *)self->code_gpa);
+ memcpy((void *)self->code_hva, &test_mem_pgm, PAGE_SIZE);
+
+ run->psw_mask = 0x0400000180000000ULL; /* DAT enabled + 64 bit mode */
+ run->psw_addr = self->code_gpa;
+ ASSERT_EQ(0, uc_run_once(self));
+ ASSERT_EQ(0, sync_regs->gprs[0]);
+ ASSERT_EQ(KVM_EXIT_S390_SIEIC, run->exit_reason);
+ ASSERT_EQ(ICPT_STOP, sie_block->icptcode);
+ ASSERT_EQ(true, uc_handle_exit(self));
+
+ /* set register content for test_mem_pgm 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 witch 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(UC_PIC_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);
+ 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 map 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(true, uc_handle_exit(self));
+}
+
TEST_F(uc_kvm, uc_gprs)
{
struct kvm_s390_sie_block *sie_block = self->sie_block;
--
2.45.2