From patchwork Thu Mar 26 19:31:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Robert Foley X-Patchwork-Id: 1262223 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=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=M5Js6u4o; dkim-atps=neutral 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 48pFtq0mCZz9sSH for ; Fri, 27 Mar 2020 06:49:39 +1100 (AEDT) Received: from localhost ([::1]:58927 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jHYVV-0001uU-1w for incoming@patchwork.ozlabs.org; Thu, 26 Mar 2020 15:49:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58851) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jHYKc-00079d-1G for qemu-devel@nongnu.org; Thu, 26 Mar 2020 15:38:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jHYKa-0001je-K1 for qemu-devel@nongnu.org; Thu, 26 Mar 2020 15:38:21 -0400 Received: from mail-qt1-x82d.google.com ([2607:f8b0:4864:20::82d]:33750) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1jHYKa-0001j9-GT for qemu-devel@nongnu.org; Thu, 26 Mar 2020 15:38:20 -0400 Received: by mail-qt1-x82d.google.com with SMTP id c14so6574278qtp.0 for ; Thu, 26 Mar 2020 12:38:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ShxiiQVChFNUTjmYIyg4bNMUbV8gv91VOcC+VfAQzoI=; b=M5Js6u4oh8aYD/tFpbvxD/w5+X/QYDJAeGo+rIjgizoVoa5zFhQoCCNTzqgv6qw2UU r9dTtv9J+G2iFj9Rn1g501SzPYq6ILY2thg+9+68QCLwJxc7eNIg4eEHqp91gwc7EaBy 6/xvkAntXcoM5an4TadSuN2bc2MukxrxOH72j6LvAa+r/B1vjamh9aGt1ZgnQZOit8++ 2dShacu0Mm7xvhlTG1deVm9hF4X704FmKaco1++dVw/G6Sw3jUXaF0OtnVj72HEOwpY2 tRg5YrYF+7m6KeJXru1Uwn/CG0StZd9/Qy7U0l58IHAbR+176EYGrEwYTYinHv0q0QtR Qnfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ShxiiQVChFNUTjmYIyg4bNMUbV8gv91VOcC+VfAQzoI=; b=YyriN/lgUUc6eRXxeOOKpcqGOZ7kYkxg2X10Elyyi+vnZBvHBrEKshSn+nFF4k0wm8 dpZZ1t863uk+jBYV/hr1s1pgBuQc8tluNxca88icQDdD5YZkmzNh9sFcu+ZQ/qk1Cm0o WET3IYwU6vwz7liDd2wN9WsqHfMAvNewVKrpOzIACD//nfr6vadRGBxDv2vWP2v6J3Bm ikkHGrzf5ImLxfdJXNG0nCPyfwSsAzL31/MZeu9vqbHJrYHnn8wshmpF1h/56Dn6q5k9 BF30CkloKTl8kbPNP0u97n9YXhu3yRf8Fj6jw5RcHA96uW3GSo+M3OSlLV/hgj4Wi0JY yvRA== X-Gm-Message-State: ANhLgQ0amRT1X8bk9S+21kloQohyDqGemaqKqpzy5uU7DWVs0zj3toit c2ByKAfq5HZ7qCS0UZXtiYkrktFbx4/f6g== X-Google-Smtp-Source: ADFU+vv/4y371roGO0+7dLaZKhPD/oc5VStpwf1kTl6jFWy4YqALbsYfvvBDGR3bQgajaeDdWdEPPg== X-Received: by 2002:ac8:2a8d:: with SMTP id b13mr9859335qta.90.1585251499002; Thu, 26 Mar 2020 12:38:19 -0700 (PDT) Received: from Rfoley-MA01.hsd1.ma.comcast.net ([2601:199:4480:60c0:fd55:4e67:1038:8302]) by smtp.gmail.com with ESMTPSA id u51sm2161916qth.46.2020.03.26.12.38.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2020 12:38:18 -0700 (PDT) From: Robert Foley To: qemu-devel@nongnu.org Subject: [PATCH v8 33/74] cpu: define cpu_interrupt_request helpers Date: Thu, 26 Mar 2020 15:31:15 -0400 Message-Id: <20200326193156.4322-34-robert.foley@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200326193156.4322-1-robert.foley@linaro.org> References: <20200326193156.4322-1-robert.foley@linaro.org> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::82d 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: richard.henderson@linaro.org, "Emilio G. Cota" , alex.bennee@linaro.org, robert.foley@linaro.org, peter.puhov@linaro.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: "Emilio G. Cota" Add a comment about how atomic_read works here. The comment refers to a "BQL-less CPU loop", which will materialize toward the end of this series. Note that the modifications to cpu_reset_interrupt are there to avoid deadlock during the CPU lock transition; once that is complete, cpu_interrupt_request will be simple again. Reviewed-by: Richard Henderson Reviewed-by: Alex Bennée Signed-off-by: Emilio G. Cota Signed-off-by: Robert Foley --- hw/core/cpu.c | 27 +++++++++++++++++++++------ include/hw/core/cpu.h | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 58 insertions(+), 6 deletions(-) diff --git a/hw/core/cpu.c b/hw/core/cpu.c index 9683d6408a..01091d0623 100644 --- a/hw/core/cpu.c +++ b/hw/core/cpu.c @@ -99,14 +99,29 @@ static void cpu_common_get_memory_mapping(CPUState *cpu, * BQL here if we need to. cpu_interrupt assumes it is held.*/ void cpu_reset_interrupt(CPUState *cpu, int mask) { - bool need_lock = !qemu_mutex_iothread_locked(); + bool has_bql = qemu_mutex_iothread_locked(); + bool has_cpu_lock = cpu_mutex_locked(cpu); - if (need_lock) { - qemu_mutex_lock_iothread(); + if (has_bql) { + if (has_cpu_lock) { + atomic_set(&cpu->interrupt_request, cpu->interrupt_request & ~mask); + } else { + cpu_mutex_lock(cpu); + atomic_set(&cpu->interrupt_request, cpu->interrupt_request & ~mask); + cpu_mutex_unlock(cpu); + } + return; + } + + if (has_cpu_lock) { + cpu_mutex_unlock(cpu); } - cpu->interrupt_request &= ~mask; - if (need_lock) { - qemu_mutex_unlock_iothread(); + qemu_mutex_lock_iothread(); + cpu_mutex_lock(cpu); + atomic_set(&cpu->interrupt_request, cpu->interrupt_request & ~mask); + qemu_mutex_unlock_iothread(); + if (!has_cpu_lock) { + cpu_mutex_unlock(cpu); } } diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h index 48b46c90ed..1c3701b142 100644 --- a/include/hw/core/cpu.h +++ b/include/hw/core/cpu.h @@ -522,6 +522,43 @@ static inline void cpu_halted_set(CPUState *cpu, uint32_t val) cpu_mutex_unlock(cpu); } +/* + * When sending an interrupt, setters OR the appropriate bit and kick the + * destination vCPU. The latter can then read interrupt_request without + * acquiring the CPU lock, because once the kick-induced completes, they'll read + * an up-to-date interrupt_request. + * Setters always acquire the lock, which guarantees that (1) concurrent + * updates from different threads won't result in data races, and (2) the + * BQL-less CPU loop will always see an up-to-date interrupt_request, since the + * loop holds the CPU lock. + */ +static inline uint32_t cpu_interrupt_request(CPUState *cpu) +{ + return atomic_read(&cpu->interrupt_request); +} + +static inline void cpu_interrupt_request_or(CPUState *cpu, uint32_t mask) +{ + if (cpu_mutex_locked(cpu)) { + atomic_set(&cpu->interrupt_request, cpu->interrupt_request | mask); + return; + } + cpu_mutex_lock(cpu); + atomic_set(&cpu->interrupt_request, cpu->interrupt_request | mask); + cpu_mutex_unlock(cpu); +} + +static inline void cpu_interrupt_request_set(CPUState *cpu, uint32_t val) +{ + if (cpu_mutex_locked(cpu)) { + atomic_set(&cpu->interrupt_request, val); + return; + } + cpu_mutex_lock(cpu); + atomic_set(&cpu->interrupt_request, val); + cpu_mutex_unlock(cpu); +} + static inline void cpu_tb_jmp_cache_clear(CPUState *cpu) { unsigned int i;