From patchwork Mon Feb 7 15:20:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 12737499 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 E2FD8C46467 for ; Mon, 7 Feb 2022 15:36:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244116AbiBGPfR (ORCPT ); Mon, 7 Feb 2022 10:35:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357335AbiBGPZD (ORCPT ); Mon, 7 Feb 2022 10:25:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6B35C0401C1 for ; Mon, 7 Feb 2022 07:25:02 -0800 (PST) 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 43FEB6149E for ; Mon, 7 Feb 2022 15:25:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42CEAC340F1; Mon, 7 Feb 2022 15:24:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644247501; bh=3CVajAIAdTOdfvfZ82kEgNvR06jRolq6At9bUSWFRwk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Rbfdop78Wtk6VDPiyaNvJ3DWupwb9ONyvU+gNt/zNLKMgKC8cWtkeWaeT2FwUZHos 3yYZAcL58Kd9bfr8pkWu23L61/DV4ZPMG2KLaAbLP90W9BF10TD1gHE5lvc9A0prum rl9cdZAdYEzq6uKM6n+yD6fwvPPv941Rs0/6hIHAZdaaRZh/YdochRv5R8oqROK5tF jHMN0iVATPYTDnN9pgZ4hX3CrKf2WnT9mTQJAkdwG2xbm9ceECHim1bY7H7XtzZupl 3fHTlv8RXepvtIYg3zFZxf3m0aHn5cDmkqyclqNQo7CpCU5+MXTltTTOHRED0h7IMD +J+Z7oFvDTmEg== 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 , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Mark Brown Subject: [PATCH v11 28/40] KVM: arm64: Handle SME host state when running guests Date: Mon, 7 Feb 2022 15:20:57 +0000 Message-Id: <20220207152109.197566-29-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220207152109.197566-1-broonie@kernel.org> References: <20220207152109.197566-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4057; h=from:subject; bh=3CVajAIAdTOdfvfZ82kEgNvR06jRolq6At9bUSWFRwk=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBiATjaipvlQdnfuu2rF6eRpP9SEhn4zU4bLewdFWFr /0NnPgmJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYgE42gAKCRAk1otyXVSH0Dy5B/ 4rEGOOj9JPsqWlDxw24euatve7GECKjYpWRjRj3kjxgCgFn59JnZvczsuHHn8mfvp1KjrJsRfAh7UY UvhtZPVXHLA15nIHtw67wtCSklYXkYnA9dYrGSyVHX1sYo2NTKDo7uwOU3RJDX82BRsOWUfxMPT6Fx g0sFs9zFEIgSTkDvLZtb2M7Wk4J2JRE4HKPKvVrhjztM6KTpvz8aEi2ye03LHOKbNGPSn7FsrE2++q huLlw6xIJ+Q5dub+nALFDNnCdFIC2eew6Y5PkG/XILvMHa+rA3tlYCw6rfOTuXNWzS/RJQik/si3Rn XdCgCo2Hl6IRxNVDU1ycK+HSBhC/3B 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 7dc85d5a6552..404b7358ba96 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -438,6 +438,7 @@ struct kvm_vcpu_arch { #define KVM_ARM64_DEBUG_STATE_SAVE_SPE (1 << 12) /* Save SPE context if active */ #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_HOST_SME_ENABLED (1 << 15) /* 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 338733ac63f8..1c585553d74f 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(); + } + } } void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu) @@ -129,6 +149,22 @@ 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);