From nobody Sat Nov 15 16:44:10 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1750178244; cv=none; d=zohomail.com; s=zohoarc; b=QCUld1XYWxSTvt7PNjy/ij8w6QviHOa6s4mr6s3uRz097qhmaR70XJFoo58ZE1LffJyN2mhdft3pHNtqzXQZdttQXnvWEVH0pI4gujmMBqC67gpJrI+l6iype0LxP927CX5wOe0malrOwk5ON16Qp5AqauvnHuIOrK0cx4WjIP4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1750178244; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=GncEdQO/d7gOZ9LM+QxKenzRx6813cX2TxyJIAl7x3Y=; b=E9V3txXG+7saHQey31mtTbKBd8aHb5TZ1r2CkPgijGsx0PNYp7tnRfAwMIfHXBTdHzrbLJlbHTNEee215iAvAl4Qu1Z/5dwAGDX8npkM3TVOm/kA9VU8Lpw/oQYlpbiT4VCvx0j7jc3z3xS3TV6Y1okeSevqo6/oWPVquVOoR9M= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1750178244185261.2962171033887; Tue, 17 Jun 2025 09:37:24 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uRZIh-0002g2-54; Tue, 17 Jun 2025 12:36:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uRZGF-0000n8-9S for qemu-devel@nongnu.org; Tue, 17 Jun 2025 12:34:15 -0400 Received: from mail-wr1-x433.google.com ([2a00:1450:4864:20::433]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1uRZGC-0000fT-SL for qemu-devel@nongnu.org; Tue, 17 Jun 2025 12:34:11 -0400 Received: by mail-wr1-x433.google.com with SMTP id ffacd0b85a97d-3a4ef2c2ef3so4913276f8f.2 for ; Tue, 17 Jun 2025 09:34:00 -0700 (PDT) Received: from draig.lan ([185.126.160.19]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a568b090b0sm14359958f8f.46.2025.06.17.09.33.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jun 2025 09:33:58 -0700 (PDT) Received: from draig.lan (localhost [IPv6:::1]) by draig.lan (Postfix) with ESMTP id 01A2B5F929; Tue, 17 Jun 2025 17:33:53 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1750178039; x=1750782839; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=GncEdQO/d7gOZ9LM+QxKenzRx6813cX2TxyJIAl7x3Y=; b=lwjeugSjNXojm8tIkAOD2mZRfEj7Ogkbcu/jJWH4hqFjJCL0caFeJctuezT8MUj6dF 0c1MLdYt4no58+X1dsA4o9r7kuhzkWTZeCUSW5PJUoLjnI4z/U6IjYvI3GNoU/c+ZVMP FoD6N9BJDnvxnWst8ah/cmJpp2Mt2HLYFeoqAiDuAzIc4uMwnX+pN4RyGxlZND3gSJwO iIhVT4Hdh1gJ/2arD1VnjWx1xC43AdCZ72oqrYTocGM4puug5JqKG3vztUiPCMCuXEWp Oo9geWdyTHWfR0zq2Gc4qubeedDW6m9aqsijp5ecTHKTCntAt7FVn5V9hcvaQI31FSSh oh0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750178039; x=1750782839; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=GncEdQO/d7gOZ9LM+QxKenzRx6813cX2TxyJIAl7x3Y=; b=eEgGYSONAd8VlS2REvyzqqGbt4xczU1GgGZM/NotvKwfhM1atbF/DQT152w1G0EEIe fPJmV1rDY3Ee9gV9CgrJijMrYEYAeu7NyjyBMDt2k4a6iUAAP4B+1VGQGf8tIjZvLrHh yrkAWme4UU5xevGiEdmUvnWqaM1p7WXCmmdCcB5/ds9woLJ+jxaiKvTcp5RUxVdSCQ4J fjyU37dsa1VKc5W01z0CEvstER8IaPngm/Wk1XRUUz3gB2gnguVYe2U5w0qfX/xbY4GS mVsub3/KX6bWXD8zcEXrfWSYZoRfQVR0cSVMqIcMb6VbrdTfv0Jk6HhHcKMyYsoOPCcq 1dXg== X-Gm-Message-State: AOJu0Yynt8byAxnqh2B3BC7g9m/qr7rr9hs8FViqZdGs8vOGq4piGwmT bcVq7/ENcNffORFFyig+8JJI0k59MaTtJn8i71EAJiw+INCQAjEAexL8iu8vdd4Pr9Y= X-Gm-Gg: ASbGnctprAGOG81EaTDpFlL2khrGhbTw22eljeh5tABlYru/woZnKLyje+xjUXRkn0a FJMxiDKbTzpBbwtW9QfHj5lPRK5zuj+v2YmoZr9R8kCer75JBZFZ9iBAq/mg8iKhMYrRGKgHlKv ZGFHvY0pe7eoLeIoVKlk8rTv+XDDaEJ113HF6KARYSAUmB3yj3yc9B0+KPnd6ThtWIMFTRx4VHx vaUc28ZC097DLufJMA1QURNiazE99ygbIaqoqQPzP8bIhgnB9Ql+W4ofE1g8peK0nuhS+BTVIlX 54+7itsIIsOkwuQhJt5a8bCtlRuyQhSM+v3boKH410a17VKZ711ow9amWCa765U= X-Google-Smtp-Source: AGHT+IEzrNJfJxccfvZ1/Dv81sv9ibMeIsZbIicjBJbFPPlnMb0UfYqycjSiQbPuRMjeJfXuxbG2YQ== X-Received: by 2002:a05:6000:400b:b0:3a4:f2ed:217e with SMTP id ffacd0b85a97d-3a5723af786mr11907985f8f.42.1750178039291; Tue, 17 Jun 2025 09:33:59 -0700 (PDT) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: qemu-devel@nongnu.org Cc: Cornelia Huck , qemu-arm@nongnu.org, Mark Burton , "Michael S. Tsirkin" , Alexander Graf , kvm@vger.kernel.org, Peter Maydell , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , =?UTF-8?q?Alex=20Benn=C3=A9e?= Subject: [RFC PATCH 11/11] kvm/arm: implement WFx traps for KVM Date: Tue, 17 Jun 2025 17:33:51 +0100 Message-ID: <20250617163351.2640572-12-alex.bennee@linaro.org> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250617163351.2640572-1-alex.bennee@linaro.org> References: <20250617163351.2640572-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::433; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x433.google.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1750178245867116600 This allows the vCPU guest core to go to sleep on a WFx instruction. Signed-off-by: Alex Benn=C3=A9e --- target/arm/kvm.c | 28 ++++++++++++++++++++++++++++ target/arm/trace-events | 1 + 2 files changed, 29 insertions(+) diff --git a/target/arm/kvm.c b/target/arm/kvm.c index 1280e2c1e8..63ba8573a2 100644 --- a/target/arm/kvm.c +++ b/target/arm/kvm.c @@ -1544,6 +1544,32 @@ static int kvm_arm_handle_hypercall(ARMCPU *cpu, return 0; } =20 +/* + * It would be perfectly fine to immediately return from any WFE/WFI + * trap however that would mean we spend a lot of time bouncing + * between the hypervisor and QEMU when things are idle. + */ + +static const char * wfx_insn[] =3D { + "WFI", + "WFE", + "WFIT", + "WFET" +}; + +static int kvm_arm_handle_wfx(CPUState *cs, int esr_iss) +{ + int ti =3D extract32(esr_iss, 0, 2); + ARMCPU *cpu =3D ARM_CPU(cs); + CPUARMState *env =3D &cpu->env; + + trace_kvm_wfx_trap(cs->cpu_index, wfx_insn[ti], env->pc); + + /* stop the CPU, return to the top of the loop */ + cs->stop =3D true; + return EXCP_YIELD; +} + /** * kvm_arm_handle_hard_trap: * @cpu: ARMCPU @@ -1582,6 +1608,8 @@ static int kvm_arm_handle_hard_trap(ARMCPU *cpu, case EC_AA64_HVC: case EC_AA64_SMC: return kvm_arm_handle_hypercall(cpu, esr_ec); + case EC_WFX_TRAP: + return kvm_arm_handle_wfx(cs, esr_iss); default: qemu_log_mask(LOG_UNIMP, "%s: unhandled EC: %x/%x/%x/%d\n", __func__, esr_ec, esr_iss, esr_iss2, esr_il); diff --git a/target/arm/trace-events b/target/arm/trace-events index 10cdba92a3..bb02da12ab 100644 --- a/target/arm/trace-events +++ b/target/arm/trace-events @@ -16,3 +16,4 @@ kvm_arm_fixup_msi_route(uint64_t iova, uint64_t gpa) "MSI= iova =3D 0x%"PRIx64" is kvm_sysreg_read(const char *name, uint64_t val) "%s =3D> 0x%" PRIx64 kvm_sysreg_write(const char *name, uint64_t val) "%s <=3D 0x%" PRIx64 kvm_hypercall(int ec, uint64_t arg0) "%d: %"PRIx64 +kvm_wfx_trap(int vcpu, const char *insn, uint64_t vaddr) "%d: %s @ 0x%" PR= Ix64 --=20 2.47.2