From patchwork Mon May 15 17:30:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13241905 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C4C8C7EE25 for ; Mon, 15 May 2023 17:49:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244777AbjEORtD (ORCPT ); Mon, 15 May 2023 13:49:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244633AbjEORs1 (ORCPT ); Mon, 15 May 2023 13:48:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 797F08685 for ; Mon, 15 May 2023 10:46:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4CD0362EFC for ; Mon, 15 May 2023 17:46:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9467DC433EF; Mon, 15 May 2023 17:46:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684172811; bh=GhL26pajIRIB9DzLhwrqVTLePORWvL+DKcE4AymgfGI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KU8O1yMT/1a4jI7Qu7dGIC0m6tN3T5k9Y9JFe2+kSQdfmGFO6LFhwni+uc+aG5S3z YTuuiZiY5/M+q8N2DOm+gP5KFROQwYA2a1zIqr7w47TzJJZLOT7r75bdAMblL4K5NB 2l8/YIefKsjlJKxQsjNZ4kGB8F19zZFImDxt5hU/N/jeh7+Md/tFzckw5/Hm4B6cOB 2pkDrHh3ztaWl6ihQe3EyvQgdjxq80Whymn6kB3FHsmyGMPiYC+mq1uDEr2vwYjGH3 NBeKwiv9O2MqXooOvIbXqpqSCU785jw0cKNwcX3+EkpEV+6UMlsK8d1cfyLNUJpN/M S1s/KuzehwTrQ== 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 1pyc2h-00FJAF-9R; Mon, 15 May 2023 18:31:27 +0100 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandru Elisei , Andre Przywara , Chase Conklin , Christoffer Dall , Ganapatrao Kulkarni , Darren Hart , Jintack Lim , Russell King , Miguel Luis , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH v10 15/59] KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg() Date: Mon, 15 May 2023 18:30:19 +0100 Message-Id: <20230515173103.1017669-16-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230515173103.1017669-1-maz@kernel.org> References: <20230515173103.1017669-1-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, alexandru.elisei@arm.com, andre.przywara@arm.com, chase.conklin@arm.com, christoffer.dall@arm.com, gankulkarni@os.amperecomputing.com, darren@os.amperecomputing.com, jintack@cs.columbia.edu, rmk+kernel@armlinux.org.uk, miguel.luis@oracle.com, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM internally uses accessor functions when reading or writing the guest's system registers. This takes care of accessing either the stored copy or using the "live" EL1 system registers when the host uses VHE. With the introduction of virtual EL2 we add a bunch of EL2 system registers, which now must also be taken care of: - If the guest is running in vEL2, and we access an EL1 sysreg, we must revert to the stored version of that, and not use the CPU's copy. - If the guest is running in vEL1, and we access an EL2 sysreg, we must also use the stored version, since the CPU carries the EL1 copy. - Some EL2 system registers are supposed to affect the current execution of the system, so we need to put them into their respective EL1 counterparts. For this we need to define a mapping between the two. This is done using the newly introduced struct el2_sysreg_map. - Some EL2 system registers have a different format than their EL1 counterpart, so we need to translate them before writing them to the CPU. This is done using an (optional) translate function in the map. - There are the three special registers SP_EL2, SPSR_EL2 and ELR_EL2, which need some separate handling (SPSR_EL2 is being handled in a separate patch). All of these cases are now wrapped into the existing accessor functions, so KVM users wouldn't need to care whether they access EL2 or EL1 registers and also which state the guest is in. This handles what was formerly known as the "shadow state" dynamically, without requiring a separate copy for each vCPU EL. Reviewed-by: Ganapatrao Kulkarni Reviewed-by: Alexandru Elisei Reviewed-by: Russell King (Oracle) Co-developed-by: Andre Przywara Signed-off-by: Andre Przywara Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 143 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 138 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 77f8bc64148a..6e5783655b03 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -63,24 +63,157 @@ static bool write_to_read_only(struct kvm_vcpu *vcpu, return false; } +#define PURE_EL2_SYSREG(el2) \ + case el2: { \ + *el1r = el2; \ + return true; \ + } + +#define MAPPED_EL2_SYSREG(el2, el1, fn) \ + case el2: { \ + *xlate = fn; \ + *el1r = el1; \ + return true; \ + } + +static bool get_el2_to_el1_mapping(unsigned int reg, + unsigned int *el1r, u64 (**xlate)(u64)) +{ + switch (reg) { + PURE_EL2_SYSREG( VPIDR_EL2 ); + PURE_EL2_SYSREG( VMPIDR_EL2 ); + PURE_EL2_SYSREG( ACTLR_EL2 ); + PURE_EL2_SYSREG( HCR_EL2 ); + PURE_EL2_SYSREG( MDCR_EL2 ); + PURE_EL2_SYSREG( HSTR_EL2 ); + PURE_EL2_SYSREG( HACR_EL2 ); + PURE_EL2_SYSREG( VTTBR_EL2 ); + PURE_EL2_SYSREG( VTCR_EL2 ); + PURE_EL2_SYSREG( RVBAR_EL2 ); + PURE_EL2_SYSREG( TPIDR_EL2 ); + PURE_EL2_SYSREG( HPFAR_EL2 ); + PURE_EL2_SYSREG( ELR_EL2 ); + PURE_EL2_SYSREG( SPSR_EL2 ); + PURE_EL2_SYSREG( CNTHCTL_EL2 ); + MAPPED_EL2_SYSREG(SCTLR_EL2, SCTLR_EL1, + translate_sctlr_el2_to_sctlr_el1 ); + MAPPED_EL2_SYSREG(CPTR_EL2, CPACR_EL1, + translate_cptr_el2_to_cpacr_el1 ); + MAPPED_EL2_SYSREG(TTBR0_EL2, TTBR0_EL1, + translate_ttbr0_el2_to_ttbr0_el1 ); + MAPPED_EL2_SYSREG(TTBR1_EL2, TTBR1_EL1, NULL ); + MAPPED_EL2_SYSREG(TCR_EL2, TCR_EL1, + translate_tcr_el2_to_tcr_el1 ); + MAPPED_EL2_SYSREG(VBAR_EL2, VBAR_EL1, NULL ); + MAPPED_EL2_SYSREG(AFSR0_EL2, AFSR0_EL1, NULL ); + MAPPED_EL2_SYSREG(AFSR1_EL2, AFSR1_EL1, NULL ); + MAPPED_EL2_SYSREG(ESR_EL2, ESR_EL1, NULL ); + MAPPED_EL2_SYSREG(FAR_EL2, FAR_EL1, NULL ); + MAPPED_EL2_SYSREG(MAIR_EL2, MAIR_EL1, NULL ); + MAPPED_EL2_SYSREG(AMAIR_EL2, AMAIR_EL1, NULL ); + default: + return false; + } +} + u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg) { u64 val = 0x8badf00d8badf00d; + u64 (*xlate)(u64) = NULL; + unsigned int el1r; - if (vcpu_get_flag(vcpu, SYSREGS_ON_CPU) && - __vcpu_read_sys_reg_from_cpu(reg, &val)) + if (!vcpu_get_flag(vcpu, SYSREGS_ON_CPU)) + goto memory_read; + + if (unlikely(get_el2_to_el1_mapping(reg, &el1r, &xlate))) { + if (!is_hyp_ctxt(vcpu)) + goto memory_read; + + /* + * ELR_EL2 is special cased for now. + */ + switch (reg) { + case ELR_EL2: + return read_sysreg_el1(SYS_ELR); + } + + /* + * If this register does not have an EL1 counterpart, + * then read the stored EL2 version. + */ + if (reg == el1r) + goto memory_read; + + /* + * If we have a non-VHE guest and that the sysreg + * requires translation to be used at EL1, use the + * in-memory copy instead. + */ + if (!vcpu_el2_e2h_is_set(vcpu) && xlate) + goto memory_read; + + /* Get the current version of the EL1 counterpart. */ + WARN_ON(!__vcpu_read_sys_reg_from_cpu(el1r, &val)); + return val; + } + + /* EL1 register can't be on the CPU if the guest is in vEL2. */ + if (unlikely(is_hyp_ctxt(vcpu))) + goto memory_read; + + if (__vcpu_read_sys_reg_from_cpu(reg, &val)) return val; +memory_read: return __vcpu_sys_reg(vcpu, reg); } void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) { - if (vcpu_get_flag(vcpu, SYSREGS_ON_CPU) && - __vcpu_write_sys_reg_to_cpu(val, reg)) + u64 (*xlate)(u64) = NULL; + unsigned int el1r; + + if (!vcpu_get_flag(vcpu, SYSREGS_ON_CPU)) + goto memory_write; + + if (unlikely(get_el2_to_el1_mapping(reg, &el1r, &xlate))) { + if (!is_hyp_ctxt(vcpu)) + goto memory_write; + + /* + * Always store a copy of the write to memory to avoid having + * to reverse-translate virtual EL2 system registers for a + * non-VHE guest hypervisor. + */ + __vcpu_sys_reg(vcpu, reg) = val; + + switch (reg) { + case ELR_EL2: + write_sysreg_el1(val, SYS_ELR); + return; + } + + /* No EL1 counterpart? We're done here.? */ + if (reg == el1r) + return; + + if (!vcpu_el2_e2h_is_set(vcpu) && xlate) + val = xlate(val); + + /* Redirect this to the EL1 version of the register. */ + WARN_ON(!__vcpu_write_sys_reg_to_cpu(val, el1r)); + return; + } + + /* EL1 register can't be on the CPU if the guest is in vEL2. */ + if (unlikely(is_hyp_ctxt(vcpu))) + goto memory_write; + + if (__vcpu_write_sys_reg_to_cpu(val, reg)) return; - __vcpu_sys_reg(vcpu, reg) = val; +memory_write: + __vcpu_sys_reg(vcpu, reg) = val; } /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */