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@xxxxxxxxxx>
> ---
> .../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, ®s);
> 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
