From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id AAAA1C282DE for ; Thu, 13 Mar 2025 10:27:13 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tsfmK-0001if-4m; Thu, 13 Mar 2025 06:27:04 -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 1tsfmD-0001hD-ML for qemu-devel@nongnu.org; Thu, 13 Mar 2025 06:26:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tsfmB-0003E9-Gj for qemu-devel@nongnu.org; Thu, 13 Mar 2025 06:26:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741861613; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZPElpu3XonC/2Dj+bha+vi8Ozhn2t3cwzD18wNczoHg=; b=YooVfZbtiuoPv3OUuFwL/tN6U1QvJ5r6QeHIgX1Kyn/z+FtntRyLCB2v7weYGJdl8EQB6t s+VEPHulucAtTLGBSB/1xVNazWT4NHsWAlNI+VTvo/gYBET9corhyOtKunY7DP15G34W2P VkBXGPzkRLk1KS8iPLCS0vRVwHzgHLo= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-530-6MxFWrWuN4yw8PiwkOmEfw-1; Thu, 13 Mar 2025 06:26:51 -0400 X-MC-Unique: 6MxFWrWuN4yw8PiwkOmEfw-1 X-Mimecast-MFC-AGG-ID: 6MxFWrWuN4yw8PiwkOmEfw_1741861610 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9612E1956048; Thu, 13 Mar 2025 10:26:49 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.22.74.4]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6EEE4300376F; Thu, 13 Mar 2025 10:26:47 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id A7D7821E675E; Thu, 13 Mar 2025 11:26:43 +0100 (CET) From: Markus Armbruster To: Bibo Mao Cc: Song Gao , Jiaxun Yang , qemu-devel@nongnu.org, Markus Armbruster , Paolo Bonzini Subject: Re: [PATCH 1/3] target/loongarch: Return directly when detect KVM disabled features In-Reply-To: <20250313091350.3770394-2-maobibo@loongson.cn> (Bibo Mao's message of "Thu, 13 Mar 2025 17:13:48 +0800") References: <20250313091350.3770394-1-maobibo@loongson.cn> <20250313091350.3770394-2-maobibo@loongson.cn> Date: Thu, 13 Mar 2025 11:26:43 +0100 Message-ID: <87a59pb50c.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Suggest something like arget/loongarch: Fix error handling of KVM feature checks That way, the nature of the patch (it's an error handling bug fix) is obvious at a glance. Bibo Mao writes: > For some paravirt KVM features, if user forces to enable it however > KVM does not support, qemu should fail to run. Here set error message > and return directly in function kvm_arch_init_vcpu(). > Please add Fixes: 6edd2a9bec90 (target/loongarch/kvm: Implement LoongArch PMU extension) Fixes: 936c3f4d7916 (target/loongarch: Use auto method with LSX feature) Fixes: 5e360dabedb1 (target/loongarch: Use auto method with LASX feature) Fixes: 620d9bd0022e (target/loongarch: Add paravirt ipi feature detection) > Signed-off-by: Bibo Mao > --- > target/loongarch/kvm/kvm.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c > index 28735c80be..b7f370ba97 100644 > --- a/target/loongarch/kvm/kvm.c > +++ b/target/loongarch/kvm/kvm.c int kvm_arch_init_vcpu(CPUState *cs) { uint64_t val; int ret; Error *local_err = NULL; ret = 0; Please drop this assignment, it's useless. qemu_add_vm_change_state_handler(kvm_loongarch_vm_stage_change, cs); if (!kvm_get_one_reg(cs, KVM_REG_LOONGARCH_DEBUG_INST, &val)) { brk_insn = val; } > @@ -1091,21 +1091,25 @@ int kvm_arch_init_vcpu(CPUState *cs) > ret = kvm_cpu_check_lsx(cs, &local_err); > if (ret < 0) { > error_report_err(local_err); > + return ret; > } > > ret = kvm_cpu_check_lasx(cs, &local_err); > if (ret < 0) { > error_report_err(local_err); > + return ret; > } > > ret = kvm_cpu_check_lbt(cs, &local_err); > if (ret < 0) { > error_report_err(local_err); > + return ret; > } > > ret = kvm_cpu_check_pmu(cs, &local_err); > if (ret < 0) { > error_report_err(local_err); > + return ret; > } > Recommend to > ret = kvm_cpu_check_pv_features(cs, &local_err); if (ret < 0) { error_report_err(local_err); + return ret; } - return ret; return 0; } Why? Have a look at commit 6edd2a9bec90: @@ -793,6 +828,12 @@ int kvm_arch_init_vcpu(CPUState *cs) if (ret < 0) { error_report_err(local_err); } + + ret = kvm_cpu_check_pmu(cs, &local_err); + if (ret < 0) { + error_report_err(local_err); + } + return ret; } The new call broke the previous call's error handling. Easy mistake to make. Less easy with my version. With that Reviewed-by: Markus Armbruster Thanks!