From patchwork Tue Apr 19 11:22:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 563606 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 AA704C433F5 for ; Tue, 19 Apr 2022 11:25:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351375AbiDSL2T (ORCPT ); Tue, 19 Apr 2022 07:28:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351423AbiDSL17 (ORCPT ); Tue, 19 Apr 2022 07:27:59 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D229C24F33 for ; Tue, 19 Apr 2022 04:25:16 -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 ams.source.kernel.org (Postfix) with ESMTPS id 8154BB81851 for ; Tue, 19 Apr 2022 11:25:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E96EC385AA; Tue, 19 Apr 2022 11:25:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650367514; bh=ViGq+zF6izj/CNFirw1Nz+T6V2thMBCW7ReQKJIV4Zc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f/wC3LTBLl7na7R7saDeaqiMUTLLmlytjsT6KnjLcIu7T8n5hECNMlcVplrzya0hR 7qWLpGTeW4yTH5oiw18qaJHyHhwS+HlSWRXIXp7ublAjiFn8RkUeWKENKrf7YmDTnO MJLJTqOZfZmJfd17SwqWirKy439yvZrdWm1k1vsLqbbfkS674fu5SlHslT4Gh6OlnZ 8DqeDZrRebtVHEcfjVeSda2ISROdX4WJWTfKgxigQPVkUBc9KqKJJZ9IxewTWtKgFe UotNRKGfbOb2SzWj4bRX3Ik+8u78/cagwGlsrh0YaNPGGjXCf3xewrDWViEbkQiIpb 5vn6SWSdI0azQ== From: Mark Brown To: Catalin Marinas , Will Deacon , Marc Zyngier , Shuah Khan , Shuah Khan Cc: Alan Hayward , Luis Machado , Salil Akerkar , Basant Kumar Dwivedi , Szabolcs Nagy , James Morse , Alexandru Elisei , Suzuki K Poulose , Luca Salabrino , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Mark Brown Subject: [PATCH v14 26/39] KVM: arm64: Handle SME host state when running guests Date: Tue, 19 Apr 2022 12:22:34 +0100 Message-Id: <20220419112247.711548-27-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220419112247.711548-1-broonie@kernel.org> References: <20220419112247.711548-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4067; h=from:subject; bh=ViGq+zF6izj/CNFirw1Nz+T6V2thMBCW7ReQKJIV4Zc=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBiXpt885Enj0B0Fr4fwtQnKM008QGdciEJBgy4YdZq AkRBR+yJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYl6bfAAKCRAk1otyXVSH0MrgB/ 9layyxgo06k0jUEdp3vgihKnQD4a5vhH62DPhKLkpAv8f2BVVWXJ1ivGjpV/585X64xyS6X9vSLSW0 mioiww209s7UC8SOKoot3e/V6fH12eEqAsi8HQiRgaQ5wzL+EESrBkVqWb6HXz76329w5hQ+GjpcPH kUoAMDzymAJ7I3IezfVris4adMaec91uVJoRT6Ma0WJvD4uXRnNaeXz1+AaDOmCnJPwbIo6JV9SHpG YsHqvJJMkEmkPamLyCEbfX4kdQfB6mAfpSuhZ98xsIc96YbkfrdzksQbm/y+wa8SxXGO0JPS418IQ7 0TWTvVsthkOhm17lPbAmJQW6/UXhpH X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org While we don't currently support SME in guests we do currently support it for the host system so we need to take care of SME's impact, including the floating point register state, when running guests. Simiarly to SVE we need to manage the traps in CPACR_RL1, what is new is the handling of streaming mode and ZA. Normally we defer any handling of the floating point register state until the guest first uses it however if the system is in streaming mode FPSIMD and SVE operations may generate SME traps which we would need to distinguish from actual attempts by the guest to use SME. Rather than do this for the time being if we are in streaming mode when entering the guest we force the floating point state to be saved immediately and exit streaming mode, meaning that the guest won't generate SME traps for supported operations. We could handle ZA in the access trap similarly to the FPSIMD/SVE state without the disruption caused by streaming mode but for simplicity handle it the same way as streaming mode for now. This will be revisited when we support SME for guests (hopefully before SME hardware becomes available), for now it will only incur additional cost on systems with SME and even there only if streaming mode or ZA are enabled. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/fpsimd.c | 36 +++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 8a7c442d5b57..f8f0d30dd1a2 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -454,6 +454,7 @@ struct kvm_vcpu_arch { #define KVM_ARM64_DEBUG_STATE_SAVE_TRBE (1 << 13) /* Save TRBE context if active */ #define KVM_ARM64_FP_FOREIGN_FPSTATE (1 << 14) #define KVM_ARM64_ON_UNSUPPORTED_CPU (1 << 15) /* Physical CPU not in supported_cpus */ +#define KVM_ARM64_HOST_SME_ENABLED (1 << 16) /* SME enabled for EL0 */ #define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \ KVM_GUESTDBG_USE_SW_BP | \ diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 57d7ac3cfa0c..441edb9c398c 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -82,6 +82,26 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN) vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED; + + /* + * We don't currently support SME guests but if we leave + * things in streaming mode then when the guest starts running + * FPSIMD or SVE code it may generate SME traps so as a + * special case if we are in streaming mode we force the host + * state to be saved now and exit streaming mode so that we + * don't have to handle any SME traps for valid guest + * operations. Do this for ZA as well for now for simplicity. + */ + if (system_supports_sme()) { + if (read_sysreg(cpacr_el1) & CPACR_EL1_SMEN_EL0EN) + vcpu->arch.flags |= KVM_ARM64_HOST_SME_ENABLED; + + if (read_sysreg_s(SYS_SVCR_EL0) & + (SYS_SVCR_EL0_SM_MASK | SYS_SVCR_EL0_ZA_MASK)) { + vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; + fpsimd_save_and_flush_cpu_state(); + } + } } /* @@ -135,6 +155,22 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) local_irq_save(flags); + /* + * If we have VHE then the Hyp code will reset CPACR_EL1 to + * CPACR_EL1_DEFAULT and we need to reenable SME. + */ + if (has_vhe() && system_supports_sme()) { + /* Also restore EL0 state seen on entry */ + if (vcpu->arch.flags & KVM_ARM64_HOST_SME_ENABLED) + sysreg_clear_set(CPACR_EL1, 0, + CPACR_EL1_SMEN_EL0EN | + CPACR_EL1_SMEN_EL1EN); + else + sysreg_clear_set(CPACR_EL1, + CPACR_EL1_SMEN_EL0EN, + CPACR_EL1_SMEN_EL1EN); + } + if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) { if (vcpu_has_sve(vcpu)) { __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);