From patchwork Fri Sep 4 03:47:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 11755707 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 13505618 for ; Fri, 4 Sep 2020 03:53:52 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id DB3EE20578 for ; Fri, 4 Sep 2020 03:53:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="Qwsajg/q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB3EE20578 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:58196 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kE2nO-0005nS-TG for patchwork-qemu-devel@patchwork.kernel.org; Thu, 03 Sep 2020 23:53:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54802) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kE2hb-0002jh-QK; Thu, 03 Sep 2020 23:47:51 -0400 Received: from ozlabs.org ([2401:3900:2:1::2]:48803) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kE2hZ-0004wu-Qb; Thu, 03 Sep 2020 23:47:51 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 4BjNsr282wz9sW0; Fri, 4 Sep 2020 13:47:28 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1599191248; bh=WHUZRE8xBkBhoLgTp8c17urX6r5gVdkN3abjLoZHMUE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qwsajg/q15lklvtp6sxvjoNcyVdI+a0jh1tUVIa3588J2LjOtgJNHvAkm3e/f+Qez OlrF1ZcjODs1TFpmQn5ASgU/ZAr4ik5WqhIyW4o6snE3rb4J5xgQs3xca1T7MU7Bag AUXlt5PmHUDiPsR6/N1SVqtsIwQWpl2KHXpOmR4Q= From: David Gibson To: peter.maydell@linaro.org Subject: [PULL 17/30] ppc/spapr: Use start-powered-off CPUState property Date: Fri, 4 Sep 2020 13:47:06 +1000 Message-Id: <20200904034719.673626-18-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200904034719.673626-1-david@gibson.dropbear.id.au> References: <20200904034719.673626-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Received-SPF: pass client-ip=2401:3900:2:1::2; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.001, SPF_HELO_PASS=-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: Eduardo Habkost , danielhb413@gmail.com, qemu-devel@nongnu.org, groug@kaod.org, qemu-ppc@nongnu.org, bauerman@linux.ibm.com, David Gibson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Thiago Jung Bauermann PowerPC sPAPR CPUs start in the halted state, and spapr_reset_vcpu() attempts to implement this by setting CPUState::halted to 1. But that's too late for the case of hotplugged CPUs in a machine configure with 2 or more threads per core. By then, other parts of QEMU have already caused the vCPU to run in an unitialized state a couple of times. For example, ppc_cpu_reset() calls ppc_tlb_invalidate_all(), which ends up calling async_run_on_cpu(). This kicks the new vCPU while it has CPUState::halted = 0, causing QEMU to issue a KVM_RUN ioctl on the new vCPU before the guest is able to make the start-cpu RTAS call to initialize its register state. This problem doesn't seem to cause visible issues for regular guests, but on a secure guest running under the Ultravisor it does. The Ultravisor relies on being able to snoop on the start-cpu RTAS call to map vCPUs to guests, and this issue causes it to see a stray vCPU that doesn't belong to any guest. Fix by setting the start-powered-off CPUState property in spapr_create_vcpu(), which makes cpu_common_reset() initialize CPUState::halted to 1 at an earlier moment. Suggested-by: Eduardo Habkost Acked-by: David Gibson Reviewed-by: Greg Kurz Signed-off-by: Thiago Jung Bauermann Message-Id: <20200826055535.951207-4-bauerman@linux.ibm.com> Signed-off-by: David Gibson --- hw/ppc/spapr_cpu_core.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c index c4f47dcc04..2125fdac34 100644 --- a/hw/ppc/spapr_cpu_core.c +++ b/hw/ppc/spapr_cpu_core.c @@ -36,11 +36,6 @@ static void spapr_reset_vcpu(PowerPCCPU *cpu) cpu_reset(cs); - /* All CPUs start halted. CPU0 is unhalted from the machine level - * reset code and the rest are explicitly started up by the guest - * using an RTAS call */ - cs->halted = 1; - env->spr[SPR_HIOR] = 0; lpcr = env->spr[SPR_LPCR]; @@ -274,6 +269,11 @@ static PowerPCCPU *spapr_create_vcpu(SpaprCpuCore *sc, int i, Error **errp) cs = CPU(obj); cpu = POWERPC_CPU(obj); + /* + * All CPUs start halted. CPU0 is unhalted from the machine level reset code + * and the rest are explicitly started up by the guest using an RTAS call. + */ + cs->start_powered_off = true; cs->cpu_index = cc->core_id + i; spapr_set_vcpu_id(cpu, cs->cpu_index, &local_err); if (local_err) {