From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755972AbbISSBc (ORCPT ); Sat, 19 Sep 2015 14:01:32 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:32788 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422747AbbISRtA (ORCPT ); Sat, 19 Sep 2015 13:49:00 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gautham R. Shenoy" , David Gibson , Paul Mackerras Subject: [PATCH 4.2 092/120] KVM: PPC: Book3S HV: Exit on H_DOORBELL if HOST_IPI is set Date: Sat, 19 Sep 2015 10:28:52 -0700 Message-Id: <20150919171725.614698875@linuxfoundation.org> X-Mailer: git-send-email 2.5.3 In-Reply-To: <20150919171712.735441938@linuxfoundation.org> References: <20150919171712.735441938@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Gautham R. Shenoy" commit 06554d9f6cc8f0b5ec903db19726a15dfc7b09d6 upstream. The code that handles the case when we receive a H_DOORBELL interrupt has a comment which says "Hypervisor doorbell - exit only if host IPI flag set". However, the current code does not actually check if the host IPI flag is set. This is due to a comparison instruction that got missed. As a result, the current code performs the exit to host only if some sibling thread or a sibling sub-core is exiting to the host. This implies that, an IPI sent to a sibling core in (subcores-per-core != 1) mode will be missed by the host unless the sibling core is on the exit path to the host. This patch adds the missing comparison operation which will ensure that when HOST_IPI flag is set, we unconditionally exit to the host. Fixes: 66feed61cdf6 Signed-off-by: Gautham R. Shenoy Reviewed-by: David Gibson Signed-off-by: Paul Mackerras Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 1 + 1 file changed, 1 insertion(+) --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1127,6 +1127,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) cmpwi r12, BOOK3S_INTERRUPT_H_DOORBELL bne 3f lbz r0, HSTATE_HOST_IPI(r13) + cmpwi r0, 0 beq 4f b guest_exit_cont 3: