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KVM: s390: selftests: Add uc_skey VM test case

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

Storage key instruction (ISKE, SSKE and RRBE) intercepts and
Keyless-subset facility are disabled on first use, where the skeys are
setup by KVM in non ucontrol VMs.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Link: https://lore.kernel.org/r/20241108091620.289406-1-schlameuss@linux.ibm.com
Acked-by: Janosch Frank <frankja@linux.ibm.com>
[frankja@linux.ibm.com: Fixed patch prefix]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20241108091620.289406-1-schlameuss@linux.ibm.com>
This commit is contained in:
Christoph Schlameuss 2024-11-08 10:16:20 +01:00 • committed by Janosch Frank
parent ae16b0ab3b
commit 0185fbc6a2
2 changed files with 149 additions and 2 deletions
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6
tools/testing/selftests/kvm/include/s390x/processor.h
View file

@ -32,4 +32,10 @@ static inline void cpu_relax(void)
barrier();
}
/* Get the instruction length */
static inline int insn_length(unsigned char code)
{
return ((((int)code + 64) >> 7) + 1) << 1;
}
#endif

145
tools/testing/selftests/kvm/s390x/ucontrol_test.c
View file

@ -79,6 +79,33 @@ asm("test_mem_asm:\n"
" j 0b\n"
);
/* Test program manipulating storage keys */
extern char test_skey_asm[];
asm("test_skey_asm:\n"
"xgr %r0, %r0\n"
"0:\n"
" ahi %r0,1\n"
" st %r1,0(%r5,%r6)\n"
" iske %r1,%r6\n"
" ahi %r0,1\n"
" diag 0,0,0x44\n"
" sske %r1,%r6\n"
" xgr %r1,%r1\n"
" iske %r1,%r6\n"
" ahi %r0,1\n"
" diag 0,0,0x44\n"
" rrbe %r1,%r6\n"
" iske %r1,%r6\n"
" ahi %r0,1\n"
" diag 0,0,0x44\n"
" j 0b\n"
);
FIXTURE(uc_kvm)
{
struct kvm_s390_sie_block *sie_block;
@ -298,8 +325,50 @@ static void uc_handle_exit_ucontrol(FIXTURE_DATA(uc_kvm) *self)
}
}
/* verify SIEIC exit
/*
* Handle the SIEIC exit
* * fail on codes not expected in the test cases
* Returns if interception is handled / execution can be continued
*/
static void uc_skey_enable(FIXTURE_DATA(uc_kvm) *self)
{
struct kvm_s390_sie_block *sie_block = self->sie_block;
/* disable KSS */
sie_block->cpuflags &= ~CPUSTAT_KSS;
/* disable skey inst interception */
sie_block->ictl &= ~(ICTL_ISKE | ICTL_SSKE | ICTL_RRBE);
}
/*
* Handle the instruction intercept
* Returns if interception is handled / execution can be continued
*/
static bool uc_handle_insn_ic(FIXTURE_DATA(uc_kvm) *self)
{
struct kvm_s390_sie_block *sie_block = self->sie_block;
int ilen = insn_length(sie_block->ipa >> 8);
struct kvm_run *run = self->run;
switch (run->s390_sieic.ipa) {
case 0xB229: /* ISKE */
case 0xB22b: /* SSKE */
case 0xB22a: /* RRBE */
uc_skey_enable(self);
/* rewind to reexecute intercepted instruction */
run->psw_addr = run->psw_addr - ilen;
pr_info("rewind guest addr to 0x%.16llx\n", run->psw_addr);
return true;
default:
return false;
}
}
/*
* Handle the SIEIC exit
* * fail on codes not expected in the test cases
* Returns if interception is handled / execution can be continued
*/
static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
{
@ -315,7 +384,10 @@ static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
case ICPT_INST:
/* end execution in caller on intercepted instruction */
pr_info("sie instruction interception\n");
return false;
return uc_handle_insn_ic(self);
case ICPT_KSS:
uc_skey_enable(self);
return true;
case ICPT_OPEREXC:
/* operation exception */
TEST_FAIL("sie exception on %.4x%.8x", sie_block->ipa, sie_block->ipb);
@ -472,4 +544,73 @@ TEST_F(uc_kvm, uc_gprs)
ASSERT_EQ(1, sync_regs->gprs[0]);
}
TEST_F(uc_kvm, uc_skey)
{
struct kvm_s390_sie_block *sie_block = self->sie_block;
struct kvm_sync_regs *sync_regs = &self->run->s.regs;
u64 test_vaddr = VM_MEM_SIZE - (SZ_1M / 2);
struct kvm_run *run = self->run;
const 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(true, uc_handle_exit(self));
ASSERT_EQ(1, sync_regs->gprs[0]);
/* ISKE */
ASSERT_EQ(0, uc_run_once(self));
/*
* Bail out and skip the test after uc_skey_enable was executed but iske
* is still intercepted. Instructions are not handled by the kernel.
* Thus there is no need to test this here.
*/
TEST_ASSERT_EQ(0, sie_block->cpuflags & CPUSTAT_KSS);
TEST_ASSERT_EQ(0, sie_block->ictl & (ICTL_ISKE | ICTL_SSKE | ICTL_RRBE));
TEST_ASSERT_EQ(KVM_EXIT_S390_SIEIC, self->run->exit_reason);
TEST_ASSERT_EQ(ICPT_INST, sie_block->icptcode);
TEST_REQUIRE(sie_block->ipa != 0xb229);
/* ISKE contd. */
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);
/* SSKE + ISKE */
sync_regs->gprs[1] = skeyvalue;
run->kvm_dirty_regs |= KVM_SYNC_GPRS;
ASSERT_EQ(0, uc_run_once(self));
ASSERT_EQ(false, uc_handle_exit(self));
ASSERT_EQ(3, sync_regs->gprs[0]);
ASSERT_EQ(skeyvalue, sync_regs->gprs[1]);
uc_assert_diag44(self);
/* RRBE + ISKE */
sync_regs->gprs[1] = skeyvalue;
run->kvm_dirty_regs |= KVM_SYNC_GPRS;
ASSERT_EQ(0, uc_run_once(self));
ASSERT_EQ(false, uc_handle_exit(self));
ASSERT_EQ(4, sync_regs->gprs[0]);
/* assert R reset but rest of skey unchanged */
ASSERT_EQ(skeyvalue & 0xfa, sync_regs->gprs[1]);
ASSERT_EQ(0, sync_regs->gprs[1] & 0x04);
uc_assert_diag44(self);
}
TEST_HARNESS_MAIN