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,URIBL_BLOCKED,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 CB27CC4332F for ; Sun, 8 Sep 2019 13:00:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 971772081B for ; Sun, 8 Sep 2019 13:00:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567947657; bh=pBTchd+FJKjl+9zSFBuJaV0uBEFHtp2Hbcxz4KfRiV0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sz7cXdBScky3sbraKWq1FJHWoELqKpQ42sv7qMEX+4b18vkrewl+Qb2dX7nVVjAJh kT6GDs+T9LT/EE6h0Yec7s0dKD2KBeUMo+x5XT51rb9tJCNLl2cy0EvNrITTy+dVze JD1tRlpBC4VRfiuCbeGB26s4JF3nRVDlWu3EFVRc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729609AbfIHMnx (ORCPT ); Sun, 8 Sep 2019 08:43:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:58150 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729604AbfIHMnw (ORCPT ); Sun, 8 Sep 2019 08:43:52 -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 C87CA21928; Sun, 8 Sep 2019 12:43:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567946631; bh=pBTchd+FJKjl+9zSFBuJaV0uBEFHtp2Hbcxz4KfRiV0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qs9e8/6d22FhgFaHSDXhvsyp4ZpdLHoWAUMcsk4nxvZeh2po0hEB7HXeDMk75XMB2 HzWDDA3bay3D2/vhArnjf0F95X52chrQyuoSAwFPplU9NBnLdZeZBM+f2tSSnk2Nk9 AhCi0McQw25vkLMT0KBPpOhrwm766clZL5QcnWU8= 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 4.4 15/23] KVM: arm/arm64: Only skip MMIO insn once Date: Sun, 8 Sep 2019 13:41:50 +0100 Message-Id: <20190908121100.234509696@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190908121052.898169328@linuxfoundation.org> References: <20190908121052.898169328@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 ae61e2ea7255b..d2efc033ef8b4 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)) @@ -206,6 +212,7 @@ 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