From patchwork Mon Feb 10 12:31:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 232038 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 00E78C352A5 for ; Mon, 10 Feb 2020 12:35:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF8BF2173E for ; Mon, 10 Feb 2020 12:35:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338140; bh=wbUDMG5kPZQYJBpnWv7Vhe32u6T1M9aqDvqzu2loVAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=M7Vw35SygsRaY2rYdf81Zng2tGgrpk7F4S9sx/5ChPYSvocRlxXzzYx6SCifH8Gmh Ly4X+NwsjXcGLfFJdIu6CW49Xt5DyTVlAQk+9de+m4fyJ2sO9ZyetB+ddXKbE3sRl3 xhmyU5h/DjoqhmmuWtfB5CXK1HOeUnMHZj9cGAZg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728056AbgBJMfk (ORCPT ); Mon, 10 Feb 2020 07:35:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:53232 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728049AbgBJMfj (ORCPT ); Mon, 10 Feb 2020 07:35:39 -0500 Received: from localhost (unknown [209.37.97.194]) (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 EBF52208C4; Mon, 10 Feb 2020 12:35:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338138; bh=wbUDMG5kPZQYJBpnWv7Vhe32u6T1M9aqDvqzu2loVAM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ObT57h2smKyaxVGKTx89qnhPmO8WhScoBROPLO67U85oGA5I7LqUiU4vouek77k6B s/owmOS3QT3wuduTAlHXsmuvxSN8tubAQ5KEKWVl1qqg4VuvXRfUbTB3RQ66rOu3ol OFPs3xx2oDjpI84KXOHUzmcWTfBclbO567yJ2e6I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Marc Zyngier , Alexandru Elisei Subject: [PATCH 4.19 047/195] KVM: arm64: Correct PSTATE on exception entry Date: Mon, 10 Feb 2020 04:31:45 -0800 Message-Id: <20200210122310.765807240@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122305.731206734@linuxfoundation.org> References: <20200210122305.731206734@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mark Rutland commit a425372e733177eb0779748956bc16c85167af48 upstream. When KVM injects an exception into a guest, it generates the PSTATE value from scratch, configuring PSTATE.{M[4:0],DAIF}, and setting all other bits to zero. This isn't correct, as the architecture specifies that some PSTATE bits are (conditionally) cleared or set upon an exception, and others are unchanged from the original context. This patch adds logic to match the architectural behaviour. To make this simple to follow/audit/extend, documentation references are provided, and bits are configured in order of their layout in SPSR_EL2. This layout can be seen in the diagram on ARM DDI 0487E.a page C5-429. Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier Reviewed-by: Alexandru Elisei Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200108134324.46500-2-mark.rutland@arm.com Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/uapi/asm/ptrace.h | 1 arch/arm64/kvm/inject_fault.c | 70 ++++++++++++++++++++++++++++++++--- 2 files changed, 66 insertions(+), 5 deletions(-) --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -49,6 +49,7 @@ #define PSR_SSBS_BIT 0x00001000 #define PSR_PAN_BIT 0x00400000 #define PSR_UAO_BIT 0x00800000 +#define PSR_DIT_BIT 0x01000000 #define PSR_V_BIT 0x10000000 #define PSR_C_BIT 0x20000000 #define PSR_Z_BIT 0x40000000 --- a/arch/arm64/kvm/inject_fault.c +++ b/arch/arm64/kvm/inject_fault.c @@ -25,9 +25,6 @@ #include #include -#define PSTATE_FAULT_BITS_64 (PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \ - PSR_I_BIT | PSR_D_BIT) - #define CURRENT_EL_SP_EL0_VECTOR 0x0 #define CURRENT_EL_SP_ELx_VECTOR 0x200 #define LOWER_EL_AArch64_VECTOR 0x400 @@ -61,6 +58,69 @@ static u64 get_except_vector(struct kvm_ return vcpu_read_sys_reg(vcpu, VBAR_EL1) + exc_offset + type; } +/* + * When an exception is taken, most PSTATE fields are left unchanged in the + * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all + * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx + * layouts, so we don't need to shuffle these for exceptions from AArch32 EL0. + * + * For the SPSR_ELx layout for AArch64, see ARM DDI 0487E.a page C5-429. + * For the SPSR_ELx layout for AArch32, see ARM DDI 0487E.a page C5-426. + * + * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from + * MSB to LSB. + */ +static unsigned long get_except64_pstate(struct kvm_vcpu *vcpu) +{ + unsigned long sctlr = vcpu_read_sys_reg(vcpu, SCTLR_EL1); + unsigned long old, new; + + old = *vcpu_cpsr(vcpu); + new = 0; + + new |= (old & PSR_N_BIT); + new |= (old & PSR_Z_BIT); + new |= (old & PSR_C_BIT); + new |= (old & PSR_V_BIT); + + // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests) + + new |= (old & PSR_DIT_BIT); + + // PSTATE.UAO is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, page D5-2579. + + // PSTATE.PAN is unchanged unless SCTLR_ELx.SPAN == 0b0 + // SCTLR_ELx.SPAN is RES1 when ARMv8.1-PAN is not implemented + // See ARM DDI 0487E.a, page D5-2578. + new |= (old & PSR_PAN_BIT); + if (!(sctlr & SCTLR_EL1_SPAN)) + new |= PSR_PAN_BIT; + + // PSTATE.SS is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, page D2-2452. + + // PSTATE.IL is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, page D1-2306. + + // PSTATE.SSBS is set to SCTLR_ELx.DSSBS upon any exception to AArch64 + // See ARM DDI 0487E.a, page D13-3258 + if (sctlr & SCTLR_ELx_DSSBS) + new |= PSR_SSBS_BIT; + + // PSTATE.BTYPE is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, pages D1-2293 to D1-2294. + + new |= PSR_D_BIT; + new |= PSR_A_BIT; + new |= PSR_I_BIT; + new |= PSR_F_BIT; + + new |= PSR_MODE_EL1h; + + return new; +} + static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr) { unsigned long cpsr = *vcpu_cpsr(vcpu); @@ -70,7 +130,7 @@ static void inject_abt64(struct kvm_vcpu vcpu_write_elr_el1(vcpu, *vcpu_pc(vcpu)); *vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync); - *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64; + *vcpu_cpsr(vcpu) = get_except64_pstate(vcpu); vcpu_write_spsr(vcpu, cpsr); vcpu_write_sys_reg(vcpu, addr, FAR_EL1); @@ -105,7 +165,7 @@ static void inject_undef64(struct kvm_vc vcpu_write_elr_el1(vcpu, *vcpu_pc(vcpu)); *vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync); - *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64; + *vcpu_cpsr(vcpu) = get_except64_pstate(vcpu); vcpu_write_spsr(vcpu, cpsr); /*