Re: [PATCH 1/2] KVM: selftests: Implement ucall() for s390x

On Tue, Jul 30, 2019 at 12:01:11PM +0200, Thomas Huth wrote:

On s390x, we can neither exit via PIO nor MMIO, but have to use an instruction like DIAGNOSE. While we're at it, rename UCALL_PIO to UCALL_DEFAULT, since PIO only works on x86 anyway, and this way we can re-use the "default" type for the DIAGNOSE exit on s390x.

Now that ucall() is implemented, we can use it in the sync_reg_test on s390x, too.

Signed-off-by: Thomas Huth thuth@redhat.com

.../testing/selftests/kvm/include/kvm_util.h | 2 +- tools/testing/selftests/kvm/lib/ucall.c | 34 +++++++++++++++---- .../selftests/kvm/s390x/sync_regs_test.c | 6 ++-- 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index e0e66b115ef2..c37aea2e33e5 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -167,7 +167,7 @@ int vm_create_device(struct kvm_vm *vm, struct kvm_create_device *cd); /* ucall implementation types */ typedef enum {

• UCALL_PIO,

• UCALL_DEFAULT,

I'd rather we keep explicit types defined; keep PIO and add DIAG. Then we can have

/* Set default ucall types */ #if defined(__x86_64__) ucall_type = UCALL_PIO; #elif defined(__aarch64__) ucall_type = UCALL_MMIO; ucall_requires_init = true; #elif defined(__s390x__) ucall_type = UCALL_DIAG; #endif

And add an assert in get_ucall()

assert(!ucall_requires_init || ucall_initialized);

UCALL_MMIO, } ucall_type_t; diff --git a/tools/testing/selftests/kvm/lib/ucall.c b/tools/testing/selftests/kvm/lib/ucall.c index dd9a66700f96..55534dd014dc 100644 --- a/tools/testing/selftests/kvm/lib/ucall.c +++ b/tools/testing/selftests/kvm/lib/ucall.c @@ -30,7 +30,7 @@ void ucall_init(struct kvm_vm *vm, ucall_type_t type, void *arg) ucall_type = type; sync_global_to_guest(vm, ucall_type);

• if (type == UCALL_PIO)

• if (type == UCALL_DEFAULT) return;

if (type == UCALL_MMIO) { @@ -84,11 +84,18 @@ void ucall_uninit(struct kvm_vm *vm) sync_global_to_guest(vm, ucall_exit_mmio_addr); } -static void ucall_pio_exit(struct ucall *uc) +static void ucall_default_exit(struct ucall *uc) { -#ifdef __x86_64__ +#if defined(__x86_64__)

• /* Exit via PIO */ asm volatile("in %[port], %%al" : : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax");

+#elif defined(__s390x__)

• /* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */
• asm volatile ("diag 0,%0,0x501" : : "a"(uc) : "memory");

+#else

• fprintf(stderr, "No default ucall available on this architecture.\n");
• exit(1);

#endif } @@ -113,8 +120,8 @@ void ucall(uint64_t cmd, int nargs, ...) va_end(va); switch (ucall_type) {

• case UCALL_PIO:

• ucall_pio_exit(&uc);
  

• case UCALL_DEFAULT:

• ucall_default_exit(&uc);
  

  break; case UCALL_MMIO: ucall_mmio_exit(&uc);

@@ -128,15 +135,28 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc) struct ucall ucall = {}; bool got_ucall = false; -#ifdef __x86_64__

• if (ucall_type == UCALL_PIO && run->exit_reason == KVM_EXIT_IO &&

+#if defined(__x86_64__)

• if (ucall_type == UCALL_DEFAULT && run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) { struct kvm_regs regs; vcpu_regs_get(vm, vcpu_id, &regs); memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi), sizeof(ucall)); got_ucall = true; }

+#elif defined(__s390x__)

• if (ucall_type == UCALL_DEFAULT &&

•    run->exit_reason == KVM_EXIT_S390_SIEIC &&
  

•    run->s390_sieic.icptcode == 4 &&
  

•    (run->s390_sieic.ipa >> 8) == 0x83 &&    /* 0x83 means DIAGNOSE */
  

•    (run->s390_sieic.ipb >> 16) == 0x501) {
  

• int reg = run->s390_sieic.ipa & 0xf;
  

• memcpy(&ucall, addr_gva2hva(vm, run->s.regs.gprs[reg]),
  

•        sizeof(ucall));
  

• got_ucall = true;
  

• }

#endif

• if (ucall_type == UCALL_MMIO && run->exit_reason == KVM_EXIT_MMIO && run->mmio.phys_addr == (uint64_t)ucall_exit_mmio_addr) { vm_vaddr_t gva;

diff --git a/tools/testing/selftests/kvm/s390x/sync_regs_test.c b/tools/testing/selftests/kvm/s390x/sync_regs_test.c index e85ff0d69548..bbc93094519b 100644 --- a/tools/testing/selftests/kvm/s390x/sync_regs_test.c +++ b/tools/testing/selftests/kvm/s390x/sync_regs_test.c @@ -25,9 +25,11 @@ static void guest_code(void) {

• register u64 stage asm("11") = 0;
• for (;;) {

• asm volatile ("diag 0,0,0x501");
  

• asm volatile ("ahi 11,1");
  

• GUEST_SYNC(0);
  

• asm volatile ("ahi %0,1" : : "r"(stage));
  

  }

} -- 2.21.0

Thanks, drew