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 X-Spam-Level: X-Spam-Status: No, score=-17.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25CA1C433DB for ; Tue, 16 Mar 2021 17:49:18 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D74C465120 for ; Tue, 16 Mar 2021 17:49:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D74C465120 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Z/0CH2n2Dr/obH9SAkKtUcVWbKj/tzZ18SVzaydcTns=; b=Tm0XPNAXJIVRbNzOdTSkYQUYz Qq2+EU5oN1qepf1QON2UB2IZFDaOZFyUSpDrh8IYsYAQ7F5lgNNJvKm+bsC88MDALU5V+KewiGpVs ab+oTg4aI6kbhWntmX/9rKzRUvzAOiXp6GHgAuUG1MXXLmAF5d3040qSIhVr+9nbYv43hNrycWLzm J0nW07Z/JI4B5IPpR+jcwYczMCrRNNI9XlG9OYrEM+x4owk845wUp7mQQ4UcqcIl3anItZ4K/PvuJ 54cFs3+UNR09IKCtwlVIxuZ+gnUmfQRdsMiktk10sRwtryWTMdz0qwrEtcg8wx32t6bQBwCTgTuEj vS99lJApw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMDmz-001RAI-KV; Tue, 16 Mar 2021 17:47:29 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lMDmF-001Qxp-OJ for linux-arm-kernel@lists.infradead.org; Tue, 16 Mar 2021 17:46:46 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 545396512A; Tue, 16 Mar 2021 17:46:42 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lMDmC-0021ao-EX; Tue, 16 Mar 2021 17:46:40 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: James Morse , Julien Thierry , Suzuki K Poulose , Alexandru Elisei , Eric Auger , Hector Martin , Mark Rutland , kernel-team@android.com Subject: [PATCH 03/11] KVM: arm64: vgic: Be tolerant to the lack of maintenance interrupt Date: Tue, 16 Mar 2021 17:46:08 +0000 Message-Id: <20210316174617.173033-4-maz@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210316174617.173033-1-maz@kernel.org> References: <20210316174617.173033-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, eric.auger@redhat.com, marcan@marcan.st, mark.rutland@arm.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210316_174644_116953_2AE92A39 X-CRM114-Status: GOOD ( 16.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org As it turns out, not all the interrupt controllers are able to expose a vGIC maintenance interrupt as a distrete signal. And to be fair, it doesn't really matter as all we require is for *something* to kick us out of guest mode out way or another. On systems that do not expose a maintenance interrupt as such, there are two outcomes: - either the virtual CPUIF does generate an interrupt, and by the time we are back to the host the interrupt will have long been disabled (as we set ICH_HCR_EL2.EN to 0 on exit). In this case, interrupt latency is as good as it gets. - or some other event (physical timer) will take us out of the guest anyway, and the only drawback is a bad interrupt latency. So let's be tolerant to the lack of maintenance interrupt, and just let the user know that their mileage may vary... Signed-off-by: Marc Zyngier --- arch/arm64/kvm/vgic/vgic-init.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index 9b491263f5f7..00c75495fd0c 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -521,11 +521,6 @@ int kvm_vgic_hyp_init(void) if (!gic_kvm_info) return -ENODEV; - if (!gic_kvm_info->maint_irq) { - kvm_err("No vgic maintenance irq\n"); - return -ENXIO; - } - switch (gic_kvm_info->type) { case GIC_V2: ret = vgic_v2_probe(gic_kvm_info); @@ -549,6 +544,11 @@ int kvm_vgic_hyp_init(void) if (ret) return ret; + if (!kvm_vgic_global_state.maint_irq) { + kvm_err("No maintenance interrupt available, fingers crossed...\n"); + return 0; + } + ret = request_percpu_irq(kvm_vgic_global_state.maint_irq, vgic_maintenance_handler, "vgic", kvm_get_running_vcpus()); -- 2.29.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel