From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53755) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dxfaY-0005G7-Vh for qemu-devel@nongnu.org; Thu, 28 Sep 2017 16:39:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dxfaU-0003os-Vg for qemu-devel@nongnu.org; Thu, 28 Sep 2017 16:39:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37984) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dxfaU-0003oT-Pg for qemu-devel@nongnu.org; Thu, 28 Sep 2017 16:39:14 -0400 From: David Hildenbrand Date: Thu, 28 Sep 2017 22:37:08 +0200 Message-Id: <20170928203708.9376-31-david@redhat.com> In-Reply-To: <20170928203708.9376-1-david@redhat.com> References: <20170928203708.9376-1-david@redhat.com> Subject: [Qemu-devel] [PATCH v2 30/30] target/s390x: special handling when starting a CPU with WAIT PSW List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: thuth@redhat.com, cohuck@redhat.com, Christian Borntraeger , Alexander Graf , Richard Henderson , David Hildenbrand List-ID: When we try to start a CPU with a WAIT PSW, we have to take care that TCG will actually try to continue executing instructions. We must therefore really only unhalt the CPU if we don't have a WAIT PSW. Also document the special order for restart interrupts, which load a new PSW and change the state to operating. To keep KVM working, simply don't have a look at the WAIT bit when loading the PSW. Otherwise the behavior of a restart interrupt when a CPU stopped would be changed. Signed-off-by: David Hildenbrand --- target/s390x/cpu.c | 11 +++++++++-- target/s390x/sigp.c | 6 +++++- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c index e27827afb3..981f5d4f39 100644 --- a/target/s390x/cpu.c +++ b/target/s390x/cpu.c @@ -335,8 +335,15 @@ unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu) break; case CPU_STATE_OPERATING: case CPU_STATE_LOAD: - /* unhalt the cpu for common infrastructure */ - s390_cpu_unhalt(cpu); + /* + * Starting a CPU with a PSW WAIT bit set: + * KVM: handles this internally and triggers another WAIT exit. + * TCG: will actually try to continue to run. Don't unhalt, will + * be done when the CPU actually has work (an interrupt). + */ + if (!tcg_enabled() || !(cpu->env.psw.mask & PSW_MASK_WAIT)) { + s390_cpu_unhalt(cpu); + } break; default: error_report("Requested CPU state is not a valid S390 CPU state: %u", diff --git a/target/s390x/sigp.c b/target/s390x/sigp.c index 964c75a736..ac3f8e7dc2 100644 --- a/target/s390x/sigp.c +++ b/target/s390x/sigp.c @@ -232,8 +232,12 @@ static void sigp_restart(CPUState *cs, run_on_cpu_data arg) case CPU_STATE_STOPPED: /* the restart irq has to be delivered prior to any other pending irq */ cpu_synchronize_state(cs); - do_restart_interrupt(&cpu->env); + /* + * Set OPERATING (and unhalting) before loading the restart PSW. + * load_psw() will then properly halt the CPU again if necessary (TCG). + */ s390_cpu_set_state(CPU_STATE_OPERATING, cpu); + do_restart_interrupt(&cpu->env); break; case CPU_STATE_OPERATING: cpu_inject_restart(cpu); -- 2.13.5