From patchwork Sun Jan 12 16:50:28 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13936458 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AB655E77188 for ; Sun, 12 Jan 2025 16:52:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=PB67RkOsQVWXBHZ1pVN2Xuio66XUomH/IKflO/CWroU=; b=KRoKn88xYr9ctqIq+q7v8eMD1n VOnE8rjkzSBERl9jYXd5SLSBX3kPd1xeyjDjlw+DOW9nRQOCr4juB1cTN7a2knJqxdpTiIOUZJ3X1 quNrk+HOPd3xkbKlBmZvetwQvAyZeSem5f7aDzT4LtJKz6+Zdfa7/7M2DKNlwC5gfmyz3v8q01pW0 /IGZgvPAYEHtaXeHVkCNi1C8c+1YMPyS/JlTCV4Yg4Vh4WdccL8MR621q08zEyj36yLIfiFLhk5f0 trDj2zsthCcm1VQ4P46Tl68AhGwSPIEiJ9VjOh92AlthG7JHfy4RVQFn9fP3zg4EyLRf7ipFwMqT0 i9bdFntQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tX1Bs-000000035kJ-0QCb; Sun, 12 Jan 2025 16:51:56 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tX1Ac-000000035c8-2rGM for linux-arm-kernel@lists.infradead.org; Sun, 12 Jan 2025 16:50:39 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 8ABA1A406C6; Sun, 12 Jan 2025 16:48:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5AE3BC4CEE0; Sun, 12 Jan 2025 16:50:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736700637; bh=Xy1v5LbX4zOHiM5PEsmTxnSA3nlKDyqAo9G46Zj857I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F7g3rPXbv5V8IkvqNAWh4Ce+TU+l/kHr9RKs8fqsDSotPjNkszahaBjQ+adIu4dWd +v72GVwc/ScMiyW7s9lj3RlkoT5o2E6oqw8gfYMLaRXS8SwgsrHPNLuoVIQovY1OPM RPJPZQBjryrM/DddIFi8PE10J7buWv/VKHbB+Bg4+0VGUNNbUVhYF+WveLzPX8iGRe 9cll7QnF4MoTfN7caQItJ4GbOm33V6d7cBuH5nzxfQox0OT/F+FAmm3S9PFsXK8eAg 3dIKjhq/eVWpc7DOVKEO2/s38yVeNx6o+gciy40VO1F3hw3xoOrVJijugB24ABnH3U eTYX5Z8lzOK/Q== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1tX1AZ-00BNnv-BP; Sun, 12 Jan 2025 16:50:35 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Joey Gouly Subject: [PATCH 1/2] KVM: arm64: nv: Always evaluate HCR_EL2 using sanitising accessors Date: Sun, 12 Jan 2025 16:50:28 +0000 Message-Id: <20250112165029.1181056-2-maz@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250112165029.1181056-1-maz@kernel.org> References: <20250112165029.1181056-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, joey.gouly@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, Joey.Gouly@arm.com 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-20250112_085038_854880_40F0D1B6 X-CRM114-Status: GOOD ( 18.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org A lot of the NV code depends on HCR_EL2.{E2H,TGE}, and we assume in places that at least HCR_EL2.E2H is invariant for a given guest. However, we make a point in *not* using the sanitising accessor that would enforce this, and are at the mercy of the guest doing stupid things. Clearly, that's not good. Rework the HCR_EL2 accessors to use __vcpu_sys_reg() instead, guaranteeing that the RESx settings get applied, specially when HCR_EL2.E2H is evaluated. This results in fewer accessors overall. Huge thanks to Joey who spent a long time tracking this bug down. Reported-by: Joey Gouly Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 36 ++++++++++++---------------- arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 4 ++-- 2 files changed, 17 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 333c163987a90..fad4f28ed7e81 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -184,29 +184,30 @@ static inline bool vcpu_is_el2(const struct kvm_vcpu *vcpu) return vcpu_is_el2_ctxt(&vcpu->arch.ctxt); } -static inline bool __vcpu_el2_e2h_is_set(const struct kvm_cpu_context *ctxt) +static inline bool vcpu_el2_e2h_is_set(const struct kvm_vcpu *vcpu) { return (!cpus_have_final_cap(ARM64_HAS_HCR_NV1) || - (ctxt_sys_reg(ctxt, HCR_EL2) & HCR_E2H)); + (__vcpu_sys_reg(vcpu, HCR_EL2) & HCR_E2H)); } -static inline bool vcpu_el2_e2h_is_set(const struct kvm_vcpu *vcpu) +static inline bool vcpu_el2_tge_is_set(const struct kvm_vcpu *vcpu) { - return __vcpu_el2_e2h_is_set(&vcpu->arch.ctxt); + return ctxt_sys_reg(&vcpu->arch.ctxt, HCR_EL2) & HCR_TGE; } -static inline bool __vcpu_el2_tge_is_set(const struct kvm_cpu_context *ctxt) +static inline bool is_hyp_ctxt(const struct kvm_vcpu *vcpu) { - return ctxt_sys_reg(ctxt, HCR_EL2) & HCR_TGE; -} + bool e2h, tge; + u64 hcr; -static inline bool vcpu_el2_tge_is_set(const struct kvm_vcpu *vcpu) -{ - return __vcpu_el2_tge_is_set(&vcpu->arch.ctxt); -} + if (!vcpu_has_nv(vcpu)) + return false; + + hcr = __vcpu_sys_reg(vcpu, HCR_EL2); + + e2h = (hcr & HCR_E2H); + tge = (hcr & HCR_TGE); -static inline bool __is_hyp_ctxt(const struct kvm_cpu_context *ctxt) -{ /* * We are in a hypervisor context if the vcpu mode is EL2 or * E2H and TGE bits are set. The latter means we are in the user space @@ -215,14 +216,7 @@ static inline bool __is_hyp_ctxt(const struct kvm_cpu_context *ctxt) * Note that the HCR_EL2.{E2H,TGE}={0,1} isn't really handled in the * rest of the KVM code, and will result in a misbehaving guest. */ - return vcpu_is_el2_ctxt(ctxt) || - (__vcpu_el2_e2h_is_set(ctxt) && __vcpu_el2_tge_is_set(ctxt)) || - __vcpu_el2_tge_is_set(ctxt); -} - -static inline bool is_hyp_ctxt(const struct kvm_vcpu *vcpu) -{ - return vcpu_has_nv(vcpu) && __is_hyp_ctxt(&vcpu->arch.ctxt); + return vcpu_is_el2(vcpu) || (e2h && tge) || tge; } static inline bool vcpu_is_host_el0(const struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c index 5f78a39053a79..90b018e06f2cb 100644 --- a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c @@ -216,7 +216,7 @@ void __vcpu_load_switch_sysregs(struct kvm_vcpu *vcpu) __sysreg32_restore_state(vcpu); __sysreg_restore_user_state(guest_ctxt); - if (unlikely(__is_hyp_ctxt(guest_ctxt))) { + if (unlikely(is_hyp_ctxt(vcpu))) { __sysreg_restore_vel2_state(vcpu); } else { if (vcpu_has_nv(vcpu)) { @@ -260,7 +260,7 @@ void __vcpu_put_switch_sysregs(struct kvm_vcpu *vcpu) host_ctxt = host_data_ptr(host_ctxt); - if (unlikely(__is_hyp_ctxt(guest_ctxt))) + if (unlikely(is_hyp_ctxt(vcpu))) __sysreg_save_vel2_state(vcpu); else __sysreg_save_el1_state(guest_ctxt);