From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50777) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fW09Q-0002K5-3w for qemu-devel@nongnu.org; Thu, 21 Jun 2018 10:01:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fW09N-0003Tz-18 for qemu-devel@nongnu.org; Thu, 21 Jun 2018 10:01:28 -0400 References: <20180620100825.22476-1-david@redhat.com> <20180620100825.22476-6-david@redhat.com> <0544e011-e909-6bca-e4ca-5a1caa141f4b@redhat.com> From: David Hildenbrand Message-ID: <051d6c6f-13c9-589e-a8f9-cf1439f3b751@redhat.com> Date: Thu, 21 Jun 2018 16:01:22 +0200 MIME-Version: 1.0 In-Reply-To: <0544e011-e909-6bca-e4ca-5a1caa141f4b@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 5/7] s390x/tcg: implement SET CLOCK List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth , qemu-s390x@nongnu.org Cc: qemu-devel@nongnu.org, Richard Henderson , Alexander Graf , Cornelia Huck , Christian Borntraeger On 21.06.2018 15:14, Thomas Huth wrote: > On 20.06.2018 12:08, David Hildenbrand wrote: >> This allows a guest to change its TOD. We already take care of updatin= g >> all CKC timers from within S390TODClass. >> >> Use MO_ALIGN to load the operand manually - this will properly trigger= a >> SPECIFICATION exception. >> >> Signed-off-by: David Hildenbrand >> --- >> target/s390x/helper.h | 1 + >> target/s390x/insn-data.def | 3 +-- >> target/s390x/misc_helper.c | 19 +++++++++++++++++++ >> target/s390x/translate.c | 9 +++++++++ >> 4 files changed, 30 insertions(+), 2 deletions(-) >> >> diff --git a/target/s390x/helper.h b/target/s390x/helper.h >> index 59cba86a27..97c60ca7bc 100644 >> --- a/target/s390x/helper.h >> +++ b/target/s390x/helper.h >> @@ -127,6 +127,7 @@ DEF_HELPER_4(diag, void, env, i32, i32, i32) >> DEF_HELPER_3(load_psw, noreturn, env, i64, i64) >> DEF_HELPER_FLAGS_2(spx, TCG_CALL_NO_RWG, void, env, i64) >> DEF_HELPER_FLAGS_1(stck, TCG_CALL_NO_RWG_SE, i64, env) >> +DEF_HELPER_FLAGS_2(sck, TCG_CALL_NO_RWG, i32, env, i64) >> DEF_HELPER_FLAGS_2(sckc, TCG_CALL_NO_RWG, void, env, i64) >> DEF_HELPER_FLAGS_2(sckpf, TCG_CALL_NO_RWG, void, env, i64) >> DEF_HELPER_FLAGS_1(stckc, TCG_CALL_NO_RWG, i64, env) >> diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def >> index 157619403d..5c6f33ed9c 100644 >> --- a/target/s390x/insn-data.def >> +++ b/target/s390x/insn-data.def >> @@ -997,8 +997,7 @@ >> /* SET ADDRESS SPACE CONTROL FAST */ >> C(0xb279, SACF, S, Z, 0, a2, 0, 0, sacf, 0) >> /* SET CLOCK */ >> - /* ??? Not implemented - is it necessary? */ >> - C(0xb204, SCK, S, Z, 0, 0, 0, 0, 0, 0) >> + C(0xb204, SCK, S, Z, la2, 0, 0, 0, sck, 0) >> /* SET CLOCK COMPARATOR */ >> C(0xb206, SCKC, S, Z, 0, m2_64a, 0, 0, sckc, 0) >> /* SET CLOCK PROGRAMMABLE FIELD */ >> diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c >> index d5f9f5e1d3..c9712b9476 100644 >> --- a/target/s390x/misc_helper.c >> +++ b/target/s390x/misc_helper.c >> @@ -191,6 +191,25 @@ void tcg_s390_tod_updated(CPUState *cs, run_on_cp= u_data opaque) >> helper_sckc(env, env->ckc); >> } >> =20 >> +/* Set Clock */ >> +uint32_t HELPER(sck)(CPUS390XState *env, uint64_t tod_low) >> +{ >> + S390TODState *td =3D s390_get_tod(); >> + S390TODClass *tdc =3D S390_TOD_GET_CLASS(td); >> + S390TOD tod =3D { >> + .high =3D 0, >> + .low =3D tod_low, >> + }; >> + Error *err =3D NULL; >> + >> + qemu_mutex_lock_iothread(); >> + tdc->set(td, &tod, &err); >> + qemu_mutex_unlock_iothread(); >> + g_assert(!err); >=20 > I know it currently can't happen, but still, I think it would be nicer > to use CC3 to tell the guest that something went wrong with the clock, > instead of abort QEMU here. Hmm, I thing I should either use error_abort here or do what you suggest. However, CC=3D3 means "Clock in not-operational state". And this implies that also STORE CLOCK and friends will have to fail and that we have to present a machine check. Especially, once we would implement the TOD-clock steering facility, CC=3D3 would not apply anymore= . So instead of faking something that is not architecturally correct, I think we really should just quit QEMU, as we expect this to never fail. >=20 > Thomas >=20 --=20 Thanks, David / dhildenb