From patchwork Thu Sep 13 05:33:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Neuling X-Patchwork-Id: 969256 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 429nRT6k4fz9s3x for ; Thu, 13 Sep 2018 15:35:17 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=neuling.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 429nRT5VrhzF3Rs for ; Thu, 13 Sep 2018 15:35:17 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=neuling.org X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 429nPr3FLpzF3RN for ; Thu, 13 Sep 2018 15:33:52 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=neuling.org Received: from localhost.localdomain (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id 429nPr1tKxz9s4V; Thu, 13 Sep 2018 15:33:52 +1000 (AEST) Received: by localhost.localdomain (Postfix, from userid 1000) id 2CD85EE791E; Thu, 13 Sep 2018 15:33:52 +1000 (AEST) From: Michael Neuling To: mpe@ellerman.id.au Subject: [PATCH] KVM: PPC: Book3S HV: Fix guest r11 corruption with POWER9 TM workarounds Date: Thu, 13 Sep 2018 15:33:47 +1000 Message-Id: <20180913053347.11389-1-mikey@neuling.org> X-Mailer: git-send-email 2.17.1 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mikey@neuling.org, linuxppc-dev@lists.ozlabs.org, sjitindarsingh@gmail.com, kvm-ppc@vger.kernel.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When we come into the softpatch handler (0x1500), we use r11 to store the HSRR0 for later use by the denorm handler. We also use the softpatch handler for the TM workarounds for POWER9. Unfortunately, in kvmppc_interrupt_hv we later store r11 out to the vcpu assuming it's still what we got from userspace. This causes r11 to be corrupted in the VCPU and hence when we restore the guest, we get a corrupted r11. We've seen this when running TM tests inside guests on P9. This fixes the problem by only touching r11 in the denorm case. Fixes: 4bb3c7a020 ("KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9") Cc: # 4.17+ Test-by: Suraj Jitindar Singh Reviewed-by: Paul Mackerras Signed-off-by: Michael Neuling --- arch/powerpc/kernel/exceptions-64s.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index ea04dfb8c0..2d8fc8c9da 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1314,9 +1314,7 @@ EXC_REAL_BEGIN(denorm_exception_hv, 0x1500, 0x100) #ifdef CONFIG_PPC_DENORMALISATION mfspr r10,SPRN_HSRR1 - mfspr r11,SPRN_HSRR0 /* save HSRR0 */ andis. r10,r10,(HSRR1_DENORM)@h /* denorm? */ - addi r11,r11,-4 /* HSRR0 is next instruction */ bne+ denorm_assist #endif @@ -1382,6 +1380,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) */ XVCPSGNDP32(32) denorm_done: + mfspr r11,SPRN_HSRR0 + subi r11,r11,4 mtspr SPRN_HSRR0,r11 mtcrf 0x80,r9 ld r9,PACA_EXGEN+EX_R9(r13)