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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 530C4C4332F for ; Sun, 8 Sep 2019 13:00:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E1C12082C for ; Sun, 8 Sep 2019 13:00:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567947646; bh=WD7JZOmWMKwETyoeSdIpQDaUzS9OhQQvEvg9UVgNCsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=a11AAaRJp0yTUmXTBrz9Z8PFgtNB4w5RDJ+qiwnb5oChf49cDGMOypnDyd8JcYpLH 9ftylm1D6XaivocCthjLrgjV+iWKGZXUdcX0FA/SqLJgv49U3e72dizdgNvP1bGi6L SfdrB+mPPzRRcx86QJQGofgS+c0uO7pqMI0bfiZw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729737AbfIHMoS (ORCPT ); Sun, 8 Sep 2019 08:44:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:58704 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729695AbfIHMoM (ORCPT ); Sun, 8 Sep 2019 08:44:12 -0400 Received: from localhost (unknown [62.28.240.114]) (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 81980218DE; Sun, 8 Sep 2019 12:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946652; bh=WD7JZOmWMKwETyoeSdIpQDaUzS9OhQQvEvg9UVgNCsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KYv11BsiFYeyZZbvDYHUPRKjlMbRV1G7z0520SbEzDEKZifIGcq/6tOiTHz0AjHLR uUdAWvBRuhyxMYyqyi85LqbPMm5HBL+nsm86s/y6DRSJHMik6pf9AZxdFGNGYbdIkl YfKh7S2CTV71WO8cE0qTgEVkyZgK+UacHuPQfZpg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Andrew Jones , Marc Zyngier , Sasha Levin Subject: [PATCH 4.9 16/26] KVM: arm/arm64: Only skip MMIO insn once Date: Sun, 8 Sep 2019 13:41:55 +0100 Message-Id: <20190908121106.124679233@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190908121057.216802689@linuxfoundation.org> References: <20190908121057.216802689@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 2113c5f62b7423e4a72b890bd479704aa85c81ba ] If after an MMIO exit to userspace a VCPU is immediately run with an immediate_exit request, such as when a signal is delivered or an MMIO emulation completion is needed, then the VCPU completes the MMIO emulation and immediately returns to userspace. As the exit_reason does not get changed from KVM_EXIT_MMIO in these cases we have to be careful not to complete the MMIO emulation again, when the VCPU is eventually run again, because the emulation does an instruction skip (and doing too many skips would be a waste of guest code :-) We need to use additional VCPU state to track if the emulation is complete. As luck would have it, we already have 'mmio_needed', which even appears to be used in this way by other architectures already. Fixes: 0d640732dbeb ("arm64: KVM: Skip MMIO insn after emulation") Acked-by: Mark Rutland Signed-off-by: Andrew Jones Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin --- arch/arm/kvm/mmio.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c index 08443a15e6be8..3caee91bca089 100644 --- a/arch/arm/kvm/mmio.c +++ b/arch/arm/kvm/mmio.c @@ -98,6 +98,12 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run) unsigned int len; int mask; + /* Detect an already handled MMIO return */ + if (unlikely(!vcpu->mmio_needed)) + return 0; + + vcpu->mmio_needed = 0; + if (!run->mmio.is_write) { len = run->mmio.len; if (len > sizeof(unsigned long)) @@ -200,6 +206,7 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run, run->mmio.is_write = is_write; run->mmio.phys_addr = fault_ipa; run->mmio.len = len; + vcpu->mmio_needed = 1; if (!ret) { /* We handled the access successfully in the kernel. */ -- 2.20.1