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=-10.0 required=3.0 tests=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 A5843C49ED6 for ; Mon, 9 Sep 2019 13:49:23 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 5D6022196E for ; Mon, 9 Sep 2019 13:49:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D6022196E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 117B54A5CD; Mon, 9 Sep 2019 09:49:23 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id PwP6Ji7q1gAl; Mon, 9 Sep 2019 09:49:21 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id EBC474A5DB; Mon, 9 Sep 2019 09:49:21 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D9A504A5D0 for ; Mon, 9 Sep 2019 09:49:20 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id K8R0RDjbbnp1 for ; Mon, 9 Sep 2019 09:49:19 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 28FD84A5FA for ; Mon, 9 Sep 2019 09:49:19 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F126319F6; Mon, 9 Sep 2019 06:49:18 -0700 (PDT) Received: from localhost.localdomain (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C2A6F3F59C; Mon, 9 Sep 2019 06:49:16 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH 11/17] arm64/kvm: Remove VMID rollover I-cache maintenance Date: Mon, 9 Sep 2019 14:48:01 +0100 Message-Id: <20190909134807.27978-12-maz@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190909134807.27978-1-maz@kernel.org> References: <20190909134807.27978-1-maz@kernel.org> MIME-Version: 1.0 Cc: kvm@vger.kernel.org, Andre Przywara , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu From: Mark Rutland For VPIPT I-caches, we need I-cache maintenance on VMID rollover to avoid an ABA problem. Consider a single vCPU VM, with a pinned stage-2, running with an idmap VA->IPA and idmap IPA->PA. If we don't do maintenance on rollover: // VMID A Writes insn X to PA 0xF Invalidates PA 0xF (for VMID A) I$ contains [{A,F}->X] [VMID ROLLOVER] // VMID B Writes insn Y to PA 0xF Invalidates PA 0xF (for VMID B) I$ contains [{A,F}->X, {B,F}->Y] [VMID ROLLOVER] // VMID A I$ contains [{A,F}->X, {B,F}->Y] Unexpectedly hits stale I$ line {A,F}->X. However, for PIPT and VIPT I-caches, the VMID doesn't affect lookup or constrain maintenance. Given the VMID doesn't affect PIPT and VIPT I-caches, and given VMID rollover is independent of changes to stage-2 mappings, I-cache maintenance cannot be necessary on VMID rollover for PIPT or VIPT I-caches. This patch removes the maintenance on rollover for VIPT and PIPT I-caches. At the same time, the unnecessary colons are removed from the asm statement to make it more legible. Signed-off-by: Mark Rutland Cc: Christoffer Dall Reviewed-by: James Morse Cc: Julien Thierry Cc: Suzuki K Poulose Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/tlb.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c index d49a14497715..c466060b76d6 100644 --- a/arch/arm64/kvm/hyp/tlb.c +++ b/arch/arm64/kvm/hyp/tlb.c @@ -193,6 +193,18 @@ void __hyp_text __kvm_flush_vm_context(void) { dsb(ishst); __tlbi(alle1is); - asm volatile("ic ialluis" : : ); + + /* + * VIPT and PIPT caches are not affected by VMID, so no maintenance + * is necessary across a VMID rollover. + * + * VPIPT caches constrain lookup and maintenance to the active VMID, + * so we need to invalidate lines with a stale VMID to avoid an ABA + * race after multiple rollovers. + * + */ + if (icache_is_vpipt()) + asm volatile("ic ialluis"); + dsb(ish); } -- 2.20.1 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm 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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 59713C4740C for ; 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Mon, 9 Sep 2019 06:49:16 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH 11/17] arm64/kvm: Remove VMID rollover I-cache maintenance Date: Mon, 9 Sep 2019 14:48:01 +0100 Message-Id: <20190909134807.27978-12-maz@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190909134807.27978-1-maz@kernel.org> References: <20190909134807.27978-1-maz@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190909_064919_552131_73E1A7FD X-CRM114-Status: GOOD ( 11.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , kvm@vger.kernel.org, Andre Przywara , Eric Auger , James Morse , Zenghui Yu , Alexandru Elisei , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Mark Rutland For VPIPT I-caches, we need I-cache maintenance on VMID rollover to avoid an ABA problem. Consider a single vCPU VM, with a pinned stage-2, running with an idmap VA->IPA and idmap IPA->PA. If we don't do maintenance on rollover: // VMID A Writes insn X to PA 0xF Invalidates PA 0xF (for VMID A) I$ contains [{A,F}->X] [VMID ROLLOVER] // VMID B Writes insn Y to PA 0xF Invalidates PA 0xF (for VMID B) I$ contains [{A,F}->X, {B,F}->Y] [VMID ROLLOVER] // VMID A I$ contains [{A,F}->X, {B,F}->Y] Unexpectedly hits stale I$ line {A,F}->X. However, for PIPT and VIPT I-caches, the VMID doesn't affect lookup or constrain maintenance. Given the VMID doesn't affect PIPT and VIPT I-caches, and given VMID rollover is independent of changes to stage-2 mappings, I-cache maintenance cannot be necessary on VMID rollover for PIPT or VIPT I-caches. This patch removes the maintenance on rollover for VIPT and PIPT I-caches. At the same time, the unnecessary colons are removed from the asm statement to make it more legible. Signed-off-by: Mark Rutland Cc: Christoffer Dall Reviewed-by: James Morse Cc: Julien Thierry Cc: Suzuki K Poulose Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/tlb.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c index d49a14497715..c466060b76d6 100644 --- a/arch/arm64/kvm/hyp/tlb.c +++ b/arch/arm64/kvm/hyp/tlb.c @@ -193,6 +193,18 @@ void __hyp_text __kvm_flush_vm_context(void) { dsb(ishst); __tlbi(alle1is); - asm volatile("ic ialluis" : : ); + + /* + * VIPT and PIPT caches are not affected by VMID, so no maintenance + * is necessary across a VMID rollover. + * + * VPIPT caches constrain lookup and maintenance to the active VMID, + * so we need to invalidate lines with a stale VMID to avoid an ABA + * race after multiple rollovers. + * + */ + if (icache_is_vpipt()) + asm volatile("ic ialluis"); + dsb(ish); } -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 8A762C49ED6 for ; Mon, 9 Sep 2019 13:49:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5ECBA21D79 for ; Mon, 9 Sep 2019 13:49:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568036960; bh=n/hW42NWXZIxAG6/+tQLQuIQjG58M4GNNOnl3MG6hRc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=oLSls4Z31cfdbbj7XJVjHJDRrVKoHsH4Arx6//SaBigdV5ykPhJv4VA7NKMfZhhTa BnxodiFahB3/vJUYIAMrQdDp0mXFS9vLEnFAuh7WJAw51xrp0sQWcYJ3+hexvskVun vt3z8XoGRncFCeu1Y6o+56ciCSPLOWGrKRrVbkg4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404748AbfIINtT (ORCPT ); Mon, 9 Sep 2019 09:49:19 -0400 Received: from foss.arm.com ([217.140.110.172]:50702 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729775AbfIINtT (ORCPT ); Mon, 9 Sep 2019 09:49:19 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F126319F6; Mon, 9 Sep 2019 06:49:18 -0700 (PDT) Received: from localhost.localdomain (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C2A6F3F59C; Mon, 9 Sep 2019 06:49:16 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: Alexandru Elisei , Andre Przywara , Eric Auger , James Morse , Mark Rutland , Zenghui Yu , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH 11/17] arm64/kvm: Remove VMID rollover I-cache maintenance Date: Mon, 9 Sep 2019 14:48:01 +0100 Message-Id: <20190909134807.27978-12-maz@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190909134807.27978-1-maz@kernel.org> References: <20190909134807.27978-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Mark Rutland For VPIPT I-caches, we need I-cache maintenance on VMID rollover to avoid an ABA problem. Consider a single vCPU VM, with a pinned stage-2, running with an idmap VA->IPA and idmap IPA->PA. If we don't do maintenance on rollover: // VMID A Writes insn X to PA 0xF Invalidates PA 0xF (for VMID A) I$ contains [{A,F}->X] [VMID ROLLOVER] // VMID B Writes insn Y to PA 0xF Invalidates PA 0xF (for VMID B) I$ contains [{A,F}->X, {B,F}->Y] [VMID ROLLOVER] // VMID A I$ contains [{A,F}->X, {B,F}->Y] Unexpectedly hits stale I$ line {A,F}->X. However, for PIPT and VIPT I-caches, the VMID doesn't affect lookup or constrain maintenance. Given the VMID doesn't affect PIPT and VIPT I-caches, and given VMID rollover is independent of changes to stage-2 mappings, I-cache maintenance cannot be necessary on VMID rollover for PIPT or VIPT I-caches. This patch removes the maintenance on rollover for VIPT and PIPT I-caches. At the same time, the unnecessary colons are removed from the asm statement to make it more legible. Signed-off-by: Mark Rutland Cc: Christoffer Dall Reviewed-by: James Morse Cc: Julien Thierry Cc: Suzuki K Poulose Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/tlb.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c index d49a14497715..c466060b76d6 100644 --- a/arch/arm64/kvm/hyp/tlb.c +++ b/arch/arm64/kvm/hyp/tlb.c @@ -193,6 +193,18 @@ void __hyp_text __kvm_flush_vm_context(void) { dsb(ishst); __tlbi(alle1is); - asm volatile("ic ialluis" : : ); + + /* + * VIPT and PIPT caches are not affected by VMID, so no maintenance + * is necessary across a VMID rollover. + * + * VPIPT caches constrain lookup and maintenance to the active VMID, + * so we need to invalidate lines with a stale VMID to avoid an ABA + * race after multiple rollovers. + * + */ + if (icache_is_vpipt()) + asm volatile("ic ialluis"); + dsb(ish); } -- 2.20.1