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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 5D174C43461 for ; Tue, 15 Sep 2020 10:42:48 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id CB74E21D7A for ; Tue, 15 Sep 2020 10:42:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="cXqnxHVC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB74E21D7A 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 66BB24B311; Tue, 15 Sep 2020 06:42:47 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org 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 FT-nDLlRptRO; Tue, 15 Sep 2020 06:42:46 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 255C04B32A; Tue, 15 Sep 2020 06:42:45 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B00534B302 for ; Tue, 15 Sep 2020 06:42:43 -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 AGvXNnq-08Pw for ; Tue, 15 Sep 2020 06:42:42 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 8843A4B305 for ; Tue, 15 Sep 2020 06:42:42 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 5855B2078D; Tue, 15 Sep 2020 10:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600166561; bh=wkKxKhlybGBntyOg1hln2NHkcNdtK4PSZdl0LvY4Ww0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cXqnxHVC/lNwsdNTXzNrQrUQ41aUYV5aTt9D/LVneBanDT+iQJ8Tjb8oidrX/Pq2a wV6fP6Pk9ZiH1lEghDHBiaetqE2r4ynVODp0mupOC7dhNCELdLeCvuwZUthDP3e7v3 7YjKkhAzX/x++0pukuKXN80BlhOhPLYLgN6MitZ0= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kI8Q3-00ByDU-SC; Tue, 15 Sep 2020 11:42:40 +0100 From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 1/2] KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch Date: Tue, 15 Sep 2020 11:42:17 +0100 Message-Id: <20200915104218.1284701-2-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915104218.1284701-1-maz@kernel.org> References: <20200915104218.1284701-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, kernel-team@android.com, will@kernel.org, stable@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: Will Deacon , kernel-team@android.com, stable@vger.kernel.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 KVM currently assumes that an instruction abort can never be a write. This is in general true, except when the abort is triggered by a S1PTW on instruction fetch that tries to update the S1 page tables (to set AF, for example). This can happen if the page tables have been paged out and brought back in without seeing a direct write to them (they are thus marked read only), and the fault handling code will make the PT executable(!) instead of writable. The guest gets stuck forever. In these conditions, the permission fault must be considered as a write so that the Stage-1 update can take place. This is essentially the I-side equivalent of the problem fixed by 60e21a0ef54c ("arm64: KVM: Take S1 walks into account when determining S2 write faults"). Update kvm_is_write_fault() to return true on IABT+S1PTW, and introduce kvm_vcpu_trap_is_exec_fault() that only return true when no faulting on a S1 fault. Additionally, kvm_vcpu_dabt_iss1tw() is renamed to kvm_vcpu_abt_iss1tw(), as the above makes it plain that it isn't specific to data abort. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 12 ++++++++++-- arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +- arch/arm64/kvm/mmu.c | 4 ++-- 3 files changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 49a55be2b9a2..4f618af660ba 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -298,7 +298,7 @@ static __always_inline int kvm_vcpu_dabt_get_rd(const struct kvm_vcpu *vcpu) return (kvm_vcpu_get_esr(vcpu) & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT; } -static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu) +static __always_inline bool kvm_vcpu_abt_iss1tw(const struct kvm_vcpu *vcpu) { return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_S1PTW); } @@ -306,7 +306,7 @@ static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu) static __always_inline bool kvm_vcpu_dabt_iswrite(const struct kvm_vcpu *vcpu) { return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_WNR) || - kvm_vcpu_dabt_iss1tw(vcpu); /* AF/DBM update */ + kvm_vcpu_abt_iss1tw(vcpu); /* AF/DBM update */ } static inline bool kvm_vcpu_dabt_is_cm(const struct kvm_vcpu *vcpu) @@ -335,6 +335,11 @@ static inline bool kvm_vcpu_trap_is_iabt(const struct kvm_vcpu *vcpu) return kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_IABT_LOW; } +static inline bool kvm_vcpu_trap_is_exec_fault(const struct kvm_vcpu *vcpu) +{ + return kvm_vcpu_trap_is_iabt(vcpu) && !kvm_vcpu_abt_iss1tw(vcpu); +} + static __always_inline u8 kvm_vcpu_trap_get_fault(const struct kvm_vcpu *vcpu) { return kvm_vcpu_get_esr(vcpu) & ESR_ELx_FSC; @@ -372,6 +377,9 @@ static __always_inline int kvm_vcpu_sys_get_rt(struct kvm_vcpu *vcpu) static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu) { + if (kvm_vcpu_abt_iss1tw(vcpu)) + return true; + if (kvm_vcpu_trap_is_iabt(vcpu)) return false; diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 426ef65601dd..d64c5d56c860 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -445,7 +445,7 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT && kvm_vcpu_dabt_isvalid(vcpu) && !kvm_vcpu_abt_issea(vcpu) && - !kvm_vcpu_dabt_iss1tw(vcpu); + !kvm_vcpu_abt_iss1tw(vcpu); if (valid) { int ret = __vgic_v2_perform_cpuif_access(vcpu); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f58d657a898d..9aec1ce491d2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1843,7 +1843,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_s2_mmu *mmu = vcpu->arch.hw_mmu; write_fault = kvm_is_write_fault(vcpu); - exec_fault = kvm_vcpu_trap_is_iabt(vcpu); + exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); VM_BUG_ON(write_fault && exec_fault); if (fault_status == FSC_PERM && !write_fault && !exec_fault) { @@ -2125,7 +2125,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) goto out; } - if (kvm_vcpu_dabt_iss1tw(vcpu)) { + if (kvm_vcpu_abt_iss1tw(vcpu)) { kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); ret = 1; goto out_unlock; -- 2.28.0 _______________________________________________ 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=-16.0 required=3.0 tests=BAYES_00,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 0D39EC43461 for ; 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Tue, 15 Sep 2020 10:42:45 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 5855B2078D; Tue, 15 Sep 2020 10:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600166561; bh=wkKxKhlybGBntyOg1hln2NHkcNdtK4PSZdl0LvY4Ww0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cXqnxHVC/lNwsdNTXzNrQrUQ41aUYV5aTt9D/LVneBanDT+iQJ8Tjb8oidrX/Pq2a wV6fP6Pk9ZiH1lEghDHBiaetqE2r4ynVODp0mupOC7dhNCELdLeCvuwZUthDP3e7v3 7YjKkhAzX/x++0pukuKXN80BlhOhPLYLgN6MitZ0= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kI8Q3-00ByDU-SC; Tue, 15 Sep 2020 11:42:40 +0100 From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 1/2] KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch Date: Tue, 15 Sep 2020 11:42:17 +0100 Message-Id: <20200915104218.1284701-2-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915104218.1284701-1-maz@kernel.org> References: <20200915104218.1284701-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, kernel-team@android.com, will@kernel.org, stable@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200915_064242_581592_658ED765 X-CRM114-Status: GOOD ( 19.69 ) 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: Will Deacon , kernel-team@android.com, stable@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org KVM currently assumes that an instruction abort can never be a write. This is in general true, except when the abort is triggered by a S1PTW on instruction fetch that tries to update the S1 page tables (to set AF, for example). This can happen if the page tables have been paged out and brought back in without seeing a direct write to them (they are thus marked read only), and the fault handling code will make the PT executable(!) instead of writable. The guest gets stuck forever. In these conditions, the permission fault must be considered as a write so that the Stage-1 update can take place. This is essentially the I-side equivalent of the problem fixed by 60e21a0ef54c ("arm64: KVM: Take S1 walks into account when determining S2 write faults"). Update kvm_is_write_fault() to return true on IABT+S1PTW, and introduce kvm_vcpu_trap_is_exec_fault() that only return true when no faulting on a S1 fault. Additionally, kvm_vcpu_dabt_iss1tw() is renamed to kvm_vcpu_abt_iss1tw(), as the above makes it plain that it isn't specific to data abort. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 12 ++++++++++-- arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +- arch/arm64/kvm/mmu.c | 4 ++-- 3 files changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 49a55be2b9a2..4f618af660ba 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -298,7 +298,7 @@ static __always_inline int kvm_vcpu_dabt_get_rd(const struct kvm_vcpu *vcpu) return (kvm_vcpu_get_esr(vcpu) & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT; } -static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu) +static __always_inline bool kvm_vcpu_abt_iss1tw(const struct kvm_vcpu *vcpu) { return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_S1PTW); } @@ -306,7 +306,7 @@ static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu) static __always_inline bool kvm_vcpu_dabt_iswrite(const struct kvm_vcpu *vcpu) { return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_WNR) || - kvm_vcpu_dabt_iss1tw(vcpu); /* AF/DBM update */ + kvm_vcpu_abt_iss1tw(vcpu); /* AF/DBM update */ } static inline bool kvm_vcpu_dabt_is_cm(const struct kvm_vcpu *vcpu) @@ -335,6 +335,11 @@ static inline bool kvm_vcpu_trap_is_iabt(const struct kvm_vcpu *vcpu) return kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_IABT_LOW; } +static inline bool kvm_vcpu_trap_is_exec_fault(const struct kvm_vcpu *vcpu) +{ + return kvm_vcpu_trap_is_iabt(vcpu) && !kvm_vcpu_abt_iss1tw(vcpu); +} + static __always_inline u8 kvm_vcpu_trap_get_fault(const struct kvm_vcpu *vcpu) { return kvm_vcpu_get_esr(vcpu) & ESR_ELx_FSC; @@ -372,6 +377,9 @@ static __always_inline int kvm_vcpu_sys_get_rt(struct kvm_vcpu *vcpu) static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu) { + if (kvm_vcpu_abt_iss1tw(vcpu)) + return true; + if (kvm_vcpu_trap_is_iabt(vcpu)) return false; diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 426ef65601dd..d64c5d56c860 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -445,7 +445,7 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT && kvm_vcpu_dabt_isvalid(vcpu) && !kvm_vcpu_abt_issea(vcpu) && - !kvm_vcpu_dabt_iss1tw(vcpu); + !kvm_vcpu_abt_iss1tw(vcpu); if (valid) { int ret = __vgic_v2_perform_cpuif_access(vcpu); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f58d657a898d..9aec1ce491d2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1843,7 +1843,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_s2_mmu *mmu = vcpu->arch.hw_mmu; write_fault = kvm_is_write_fault(vcpu); - exec_fault = kvm_vcpu_trap_is_iabt(vcpu); + exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); VM_BUG_ON(write_fault && exec_fault); if (fault_status == FSC_PERM && !write_fault && !exec_fault) { @@ -2125,7 +2125,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) goto out; } - if (kvm_vcpu_dabt_iss1tw(vcpu)) { + if (kvm_vcpu_abt_iss1tw(vcpu)) { kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); ret = 1; goto out_unlock; -- 2.28.0 _______________________________________________ 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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 61AC2C43461 for ; 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Tue, 15 Sep 2020 10:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600166561; bh=wkKxKhlybGBntyOg1hln2NHkcNdtK4PSZdl0LvY4Ww0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cXqnxHVC/lNwsdNTXzNrQrUQ41aUYV5aTt9D/LVneBanDT+iQJ8Tjb8oidrX/Pq2a wV6fP6Pk9ZiH1lEghDHBiaetqE2r4ynVODp0mupOC7dhNCELdLeCvuwZUthDP3e7v3 7YjKkhAzX/x++0pukuKXN80BlhOhPLYLgN6MitZ0= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kI8Q3-00ByDU-SC; Tue, 15 Sep 2020 11:42:40 +0100 From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: kernel-team@android.com, Will Deacon , stable@vger.kernel.org Subject: [PATCH v2 1/2] KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch Date: Tue, 15 Sep 2020 11:42:17 +0100 Message-Id: <20200915104218.1284701-2-maz@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915104218.1284701-1-maz@kernel.org> References: <20200915104218.1284701-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, kernel-team@android.com, will@kernel.org, stable@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM currently assumes that an instruction abort can never be a write. This is in general true, except when the abort is triggered by a S1PTW on instruction fetch that tries to update the S1 page tables (to set AF, for example). This can happen if the page tables have been paged out and brought back in without seeing a direct write to them (they are thus marked read only), and the fault handling code will make the PT executable(!) instead of writable. The guest gets stuck forever. In these conditions, the permission fault must be considered as a write so that the Stage-1 update can take place. This is essentially the I-side equivalent of the problem fixed by 60e21a0ef54c ("arm64: KVM: Take S1 walks into account when determining S2 write faults"). Update kvm_is_write_fault() to return true on IABT+S1PTW, and introduce kvm_vcpu_trap_is_exec_fault() that only return true when no faulting on a S1 fault. Additionally, kvm_vcpu_dabt_iss1tw() is renamed to kvm_vcpu_abt_iss1tw(), as the above makes it plain that it isn't specific to data abort. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 12 ++++++++++-- arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +- arch/arm64/kvm/mmu.c | 4 ++-- 3 files changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 49a55be2b9a2..4f618af660ba 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -298,7 +298,7 @@ static __always_inline int kvm_vcpu_dabt_get_rd(const struct kvm_vcpu *vcpu) return (kvm_vcpu_get_esr(vcpu) & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT; } -static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu) +static __always_inline bool kvm_vcpu_abt_iss1tw(const struct kvm_vcpu *vcpu) { return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_S1PTW); } @@ -306,7 +306,7 @@ static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu) static __always_inline bool kvm_vcpu_dabt_iswrite(const struct kvm_vcpu *vcpu) { return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_WNR) || - kvm_vcpu_dabt_iss1tw(vcpu); /* AF/DBM update */ + kvm_vcpu_abt_iss1tw(vcpu); /* AF/DBM update */ } static inline bool kvm_vcpu_dabt_is_cm(const struct kvm_vcpu *vcpu) @@ -335,6 +335,11 @@ static inline bool kvm_vcpu_trap_is_iabt(const struct kvm_vcpu *vcpu) return kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_IABT_LOW; } +static inline bool kvm_vcpu_trap_is_exec_fault(const struct kvm_vcpu *vcpu) +{ + return kvm_vcpu_trap_is_iabt(vcpu) && !kvm_vcpu_abt_iss1tw(vcpu); +} + static __always_inline u8 kvm_vcpu_trap_get_fault(const struct kvm_vcpu *vcpu) { return kvm_vcpu_get_esr(vcpu) & ESR_ELx_FSC; @@ -372,6 +377,9 @@ static __always_inline int kvm_vcpu_sys_get_rt(struct kvm_vcpu *vcpu) static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu) { + if (kvm_vcpu_abt_iss1tw(vcpu)) + return true; + if (kvm_vcpu_trap_is_iabt(vcpu)) return false; diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 426ef65601dd..d64c5d56c860 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -445,7 +445,7 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT && kvm_vcpu_dabt_isvalid(vcpu) && !kvm_vcpu_abt_issea(vcpu) && - !kvm_vcpu_dabt_iss1tw(vcpu); + !kvm_vcpu_abt_iss1tw(vcpu); if (valid) { int ret = __vgic_v2_perform_cpuif_access(vcpu); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f58d657a898d..9aec1ce491d2 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1843,7 +1843,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_s2_mmu *mmu = vcpu->arch.hw_mmu; write_fault = kvm_is_write_fault(vcpu); - exec_fault = kvm_vcpu_trap_is_iabt(vcpu); + exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); VM_BUG_ON(write_fault && exec_fault); if (fault_status == FSC_PERM && !write_fault && !exec_fault) { @@ -2125,7 +2125,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu) goto out; } - if (kvm_vcpu_dabt_iss1tw(vcpu)) { + if (kvm_vcpu_abt_iss1tw(vcpu)) { kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); ret = 1; goto out_unlock; -- 2.28.0