Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934045AbaJDAny (ORCPT ); Fri, 3 Oct 2014 20:43:54 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44721 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755024AbaJCVcs (ORCPT ); Fri, 3 Oct 2014 17:32:48 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Zyngier , Ard Biesheuvel , Christoffer Dall Subject: [PATCH 3.16 042/357] arm/arm64: KVM: Complete WFI/WFE instructions Date: Fri, 3 Oct 2014 14:27:08 -0700 Message-Id: <20141003212934.726049384@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141003212933.458851516@linuxfoundation.org> References: <20141003212933.458851516@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christoffer Dall commit 05e0127f9e362b36aa35f17b1a3d52bca9322a3a upstream. The architecture specifies that when the processor wakes up from a WFE or WFI instruction, the instruction is considered complete, however we currrently return to EL1 (or EL0) at the WFI/WFE instruction itself. While most guests may not be affected by this because their local exception handler performs an exception returning setting the event bit or with an interrupt pending, some guests like UEFI will get wedged due this little mishap. Simply skip the instruction when we have completed the emulation. Acked-by: Marc Zyngier Cc: Ard Biesheuvel Signed-off-by: Christoffer Dall Signed-off-by: Greg Kroah-Hartman --- arch/arm/kvm/handle_exit.c | 2 ++ arch/arm64/kvm/handle_exit.c | 2 ++ 2 files changed, 4 insertions(+) --- a/arch/arm/kvm/handle_exit.c +++ b/arch/arm/kvm/handle_exit.c @@ -93,6 +93,8 @@ static int kvm_handle_wfx(struct kvm_vcp else kvm_vcpu_block(vcpu); + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + return 1; } --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -66,6 +66,8 @@ static int kvm_handle_wfx(struct kvm_vcp else kvm_vcpu_block(vcpu); + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + return 1; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/