From patchwork Mon Nov 5 15:30:26 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10668511 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5B092175A for ; Mon, 5 Nov 2018 15:30:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4887D29A85 for ; Mon, 5 Nov 2018 15:30:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3C96329ABB; Mon, 5 Nov 2018 15:30:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 46D0229A85 for ; Mon, 5 Nov 2018 15:30:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=/gs4WgonzYy32MEvmZ7DVN0lT9i+R3ky56oUrXg0c+M=; b=EwyOnP+piGT0d5 3zSpfDEao31pcaCqmJXGMguOFfAOzbTEKNvqg1ulyYM5DjcsJRcR835iTWieFHomlg3Q8NorPCI6X K1uOueJUiFYBii38LI5a38KElCeA39IADHwazkVvwV6Y1qnioOJnQgcq7NS9+TmEztJn8Sx/pijDb 5ZvTS/wCNukN04m8UvgTcmmt7vw27mdrP41Vhrse1EcBTO5x6+LsfszW4rLPrX1yPyYnvNvYMOmKq Y59nUcdz7lBUucyBawCP+SAmWgDWJfzJuTa/8NDN5pbLGv44CKO5AdoWNCSQYOdTR2luH1lM6eGps MwL4b2Euo+NYm3jixRSA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gJgq2-00005p-C7; Mon, 05 Nov 2018 15:30:50 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gJgpy-0008WB-T5 for linux-arm-kernel@lists.infradead.org; Mon, 05 Nov 2018 15:30:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9AA8BA78; Mon, 5 Nov 2018 07:30:36 -0800 (PST) Received: from filthy-habits.cambridge.arm.com (filthy-habits.cambridge.arm.com [10.1.196.62]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 684013F5CF; Mon, 5 Nov 2018 07:30:35 -0800 (PST) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH] arm64: KVM: Don't generate UNDEF when LORegion feature is present Date: Mon, 5 Nov 2018 15:30:26 +0000 Message-Id: <20181105153026.169248-1-marc.zyngier@arm.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181105_073046_955548_44757D72 X-CRM114-Status: GOOD ( 14.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Maydell , Richard Henderson , Christoffer Dall Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP We currently hide the LORegion feature, and generate an UNDEF if the guest dares using the corresponding registers. This is a bit extreme, as ARMv8.1 guarantees the feature to be present. The guest should check the feature register before doing anything, but we could also give the guest some slack (read "allow the guest to be a bit stupid"). So instead of unconditionnaly deliver an exception, let's only do it when the host doesn't support LORegion at all (or when the feature has been sanitized out), and treat the registers as RAZ/WI otherwise (with the exception of LORID_EL1 being RO). Fixes: cc33c4e20185 ("arm64/kvm: Prohibit guest LOR accesses") Suggested-by: Richard Henderson Signed-off-by: Marc Zyngier Acked-by: Mark Rutland Acked-by: Christoffer Dall --- arch/arm64/kvm/sys_regs.c | 42 +++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 22fbbdbece3c..1133b74065f1 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -314,12 +314,29 @@ static bool trap_raz_wi(struct kvm_vcpu *vcpu, return read_zero(vcpu, p); } -static bool trap_undef(struct kvm_vcpu *vcpu, - struct sys_reg_params *p, - const struct sys_reg_desc *r) +/* + * ARMv8.1 mandates at least a trivial LORegion implementation, where all the + * RW registers are RES0 (which we can implement as RAZ/WI). On an ARMv8.0 + * system, these registers should UNDEF. LORID_EL1 being a RO register, we + * treat it separately. + */ +static bool trap_loregion(struct kvm_vcpu *vcpu, + struct sys_reg_params *p, + const struct sys_reg_desc *r) { - kvm_inject_undefined(vcpu); - return false; + u64 val = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + u32 sr = sys_reg((u32)r->Op0, (u32)r->Op1, + (u32)r->CRn, (u32)r->CRm, (u32)r->Op2); + + if (!(val & (0xfUL << ID_AA64MMFR1_LOR_SHIFT))) { + kvm_inject_undefined(vcpu); + return false; + } + + if (p->is_write && sr == SYS_LORID_EL1) + return write_to_read_only(vcpu, p, r); + + return trap_raz_wi(vcpu, p, r); } static bool trap_oslsr_el1(struct kvm_vcpu *vcpu, @@ -1040,11 +1057,6 @@ static u64 read_id_reg(struct sys_reg_desc const *r, bool raz) kvm_debug("SVE unsupported for guests, suppressing\n"); val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT); - } else if (id == SYS_ID_AA64MMFR1_EL1) { - if (val & (0xfUL << ID_AA64MMFR1_LOR_SHIFT)) - kvm_debug("LORegions unsupported for guests, suppressing\n"); - - val &= ~(0xfUL << ID_AA64MMFR1_LOR_SHIFT); } return val; @@ -1330,11 +1342,11 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 }, { SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 }, - { SYS_DESC(SYS_LORSA_EL1), trap_undef }, - { SYS_DESC(SYS_LOREA_EL1), trap_undef }, - { SYS_DESC(SYS_LORN_EL1), trap_undef }, - { SYS_DESC(SYS_LORC_EL1), trap_undef }, - { SYS_DESC(SYS_LORID_EL1), trap_undef }, + { SYS_DESC(SYS_LORSA_EL1), trap_loregion }, + { SYS_DESC(SYS_LOREA_EL1), trap_loregion }, + { SYS_DESC(SYS_LORN_EL1), trap_loregion }, + { SYS_DESC(SYS_LORC_EL1), trap_loregion }, + { SYS_DESC(SYS_LORID_EL1), trap_loregion }, { SYS_DESC(SYS_VBAR_EL1), NULL, reset_val, VBAR_EL1, 0 }, { SYS_DESC(SYS_DISR_EL1), NULL, reset_val, DISR_EL1, 0 },