From patchwork Wed Jan 20 22:44:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 1429473 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4DLglS5cmqz9sT6 for ; Thu, 21 Jan 2021 09:52:36 +1100 (AEDT) Received: from localhost ([::1]:50890 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2ML4-0002Yo-N8 for incoming@patchwork.ozlabs.org; Wed, 20 Jan 2021 17:52:34 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:56624) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2MDk-0003vn-4z; Wed, 20 Jan 2021 17:45:00 -0500 Received: from mail.csgraf.de ([188.138.100.120]:45230 helo=zulu616.server4you.de) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2MDg-0001WS-Ux; Wed, 20 Jan 2021 17:44:59 -0500 Received: from localhost.localdomain (dynamic-077-002-091-253.77.2.pool.telefonica.de [77.2.91.253]) by csgraf.de (Postfix) with ESMTPSA id 81B0B390057D; Wed, 20 Jan 2021 23:44:51 +0100 (CET) From: Alexander Graf To: qemu-devel@nongnu.org Subject: [PATCH v6 09/11] arm/hvf: Add a WFI handler Date: Wed, 20 Jan 2021 23:44:42 +0100 Message-Id: <20210120224444.71840-10-agraf@csgraf.de> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20210120224444.71840-1-agraf@csgraf.de> References: <20210120224444.71840-1-agraf@csgraf.de> MIME-Version: 1.0 Received-SPF: pass client-ip=188.138.100.120; envelope-from=agraf@csgraf.de; helo=zulu616.server4you.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Eduardo Habkost , Richard Henderson , Cameron Esfahani , Roman Bolshakov , qemu-arm@nongnu.org, Frank Yang , Paolo Bonzini , Peter Collingbourne Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Peter Collingbourne Sleep on WFI until the VTIMER is due but allow ourselves to be woken up on IPI. In this implementation IPI is blocked on the CPU thread at startup and pselect() is used to atomically unblock the signal and begin sleeping. The signal is sent unconditionally so there's no need to worry about races between actually sleeping and the "we think we're sleeping" state. It may lead to an extra wakeup but that's better than missing it entirely. Signed-off-by: Peter Collingbourne [agraf: Remove unused 'set' variable, always advance PC on WFX trap] Signed-off-by: Alexander Graf Acked-by: Roman Bolshakov --- accel/hvf/hvf-cpus.c | 5 ++-- include/sysemu/hvf_int.h | 1 + target/arm/hvf/hvf.c | 56 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+), 3 deletions(-) diff --git a/accel/hvf/hvf-cpus.c b/accel/hvf/hvf-cpus.c index 6d70ee742e..abef6a58f7 100644 --- a/accel/hvf/hvf-cpus.c +++ b/accel/hvf/hvf-cpus.c @@ -322,15 +322,14 @@ static int hvf_init_vcpu(CPUState *cpu) cpu->hvf = g_malloc0(sizeof(*cpu->hvf)); /* init cpu signals */ - sigset_t set; struct sigaction sigact; memset(&sigact, 0, sizeof(sigact)); sigact.sa_handler = dummy_signal; sigaction(SIG_IPI, &sigact, NULL); - pthread_sigmask(SIG_BLOCK, NULL, &set); - sigdelset(&set, SIG_IPI); + pthread_sigmask(SIG_BLOCK, NULL, &cpu->hvf->unblock_ipi_mask); + sigdelset(&cpu->hvf->unblock_ipi_mask, SIG_IPI); #ifdef __aarch64__ r = hv_vcpu_create(&cpu->hvf->fd, (hv_vcpu_exit_t **)&cpu->hvf->exit, NULL); diff --git a/include/sysemu/hvf_int.h b/include/sysemu/hvf_int.h index c2ac6c8f97..7a397fe85a 100644 --- a/include/sysemu/hvf_int.h +++ b/include/sysemu/hvf_int.h @@ -51,6 +51,7 @@ extern HVFState *hvf_state; struct hvf_vcpu_state { uint64_t fd; void *exit; + sigset_t unblock_ipi_mask; }; void assert_hvf_ok(hv_return_t ret); diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c index 8f18efe856..f0850ab14a 100644 --- a/target/arm/hvf/hvf.c +++ b/target/arm/hvf/hvf.c @@ -2,6 +2,7 @@ * QEMU Hypervisor.framework support for Apple Silicon * Copyright 2020 Alexander Graf + * Copyright 2020 Google LLC * * This work is licensed under the terms of the GNU GPL, version 2 or later. * See the COPYING file in the top-level directory. @@ -17,6 +18,8 @@ #include "sysemu/hvf_int.h" #include "sysemu/hw_accel.h" +#include + #include "exec/address-spaces.h" #include "hw/irq.h" #include "qemu/main-loop.h" @@ -411,6 +414,7 @@ int hvf_arch_init_vcpu(CPUState *cpu) void hvf_kick_vcpu_thread(CPUState *cpu) { + cpus_kick_thread(cpu); hv_vcpus_exit(&cpu->hvf->fd, 1); } @@ -466,6 +470,18 @@ static int hvf_inject_interrupts(CPUState *cpu) return 0; } +static void hvf_wait_for_ipi(CPUState *cpu, struct timespec *ts) +{ + /* + * Use pselect to sleep so that other threads can IPI us while we're + * sleeping. + */ + qatomic_mb_set(&cpu->thread_kicked, false); + qemu_mutex_unlock_iothread(); + pselect(0, 0, 0, 0, ts, &cpu->hvf->unblock_ipi_mask); + qemu_mutex_lock_iothread(); +} + int hvf_vcpu_exec(CPUState *cpu) { ARMCPU *arm_cpu = ARM_CPU(cpu); @@ -577,6 +593,46 @@ int hvf_vcpu_exec(CPUState *cpu) } case EC_WFX_TRAP: advance_pc = true; + if (!(syndrome & WFX_IS_WFE) && !(cpu->interrupt_request & + (CPU_INTERRUPT_HARD | CPU_INTERRUPT_FIQ))) { + + uint64_t ctl; + r = hv_vcpu_get_sys_reg(cpu->hvf->fd, HV_SYS_REG_CNTV_CTL_EL0, + &ctl); + assert_hvf_ok(r); + + if (!(ctl & 1) || (ctl & 2)) { + /* Timer disabled or masked, just wait for an IPI. */ + hvf_wait_for_ipi(cpu, NULL); + break; + } + + uint64_t cval; + r = hv_vcpu_get_sys_reg(cpu->hvf->fd, HV_SYS_REG_CNTV_CVAL_EL0, + &cval); + assert_hvf_ok(r); + + int64_t ticks_to_sleep = cval - mach_absolute_time(); + if (ticks_to_sleep < 0) { + break; + } + + uint64_t seconds = ticks_to_sleep / arm_cpu->gt_cntfrq_hz; + uint64_t nanos = + (ticks_to_sleep - arm_cpu->gt_cntfrq_hz * seconds) * + 1000000000 / arm_cpu->gt_cntfrq_hz; + + /* + * Don't sleep for less than 2ms. This is believed to improve + * latency of message passing workloads. + */ + if (!seconds && nanos < 2000000) { + break; + } + + struct timespec ts = { seconds, nanos }; + hvf_wait_for_ipi(cpu, &ts); + } break; case EC_AA64_HVC: cpu_synchronize_state(cpu);