From patchwork Wed Jan 26 15:11:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 537361 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 0F9B4C3526D for ; Wed, 26 Jan 2022 15:13:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235849AbiAZPNY (ORCPT ); Wed, 26 Jan 2022 10:13:24 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:41734 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235791AbiAZPNY (ORCPT ); Wed, 26 Jan 2022 10:13:24 -0500 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 64214B81C0F for ; Wed, 26 Jan 2022 15:13:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2D5BC340ED; Wed, 26 Jan 2022 15:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643210002; bh=jEyud6x1YGBVsWHdD8Q9gNLZk7/BvtyPAjeOVpneBR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s01ocj9O+vmUI+2bzrankFQh1SucDFgBAON8TER9p74KL709oSTETT1EDDlHj4utA liDB3mTOMJmL6uuT6KRVadzwuAR2InKa0wDp3u90PuuZu9TMf+ZkR+fuOwu068jTG6 qU4d/o5ZCW0Vr41MEk8o79iiylyVnUftuNOnTRdn5WrVwE8vi8ByKkQLu3D9CKkZ0U VrCQafXCzAkVUoiFGHEf1JqCnSWZ6VvTusjblX1QFceqErYgd8RgBJc4mkWSfkwjrv mCmB4Xfg2k/r0Qrg64EUArcHIz693PUMjmTn+RYZpA7f/Un3n2bXkoCLUrx0DS8juR yHkFy8wIrIKBg== 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 v9 27/40] KVM: arm64: Handle SME host state when running guests Date: Wed, 26 Jan 2022 15:11:07 +0000 Message-Id: <20220126151120.3811248-28-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220126151120.3811248-1-broonie@kernel.org> References: <20220126151120.3811248-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4080; h=from:subject; bh=jEyud6x1YGBVsWHdD8Q9gNLZk7/BvtyPAjeOVpneBR8=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBh8WSMfJFkLKCJZq4Gps4zY52BZXzbcGLbOMe99Cdt hhGcKniJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYfFkjAAKCRAk1otyXVSH0Ar+B/ 9kFLtL6e0zg6qzXXo3LYZrphaqADH0ZH9VhO7D4RPPRG4H08TRg7jwNEwCZIlT3uzQQQU390/3TNFI 9jb5XL4xekP5q35vPJivFuudpYZkKCd/6vRI7+0pMknqgwZ9kUtOp2MapmVpr5DEEyfXIaamxPc0X8 DrulZ8WwepvmNQGkyBJdy0cwqAR7EDOkVQyhC67E2iCtr+vuLeAr73XcjSEq8dcV+l1dm/vOWFLaeu SXN3evr2Hm8HR9aAU1gHRNLBbslHRc2tFraYQca7oSYBRzbKJLQPI6Lvyvtoeck14prm2Y8L7AHGEJ 0SkdEOaQcnK3Ykg5F4ilSvI16djBPC 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 --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/fpsimd.c | 38 +++++++++++++++++++++++++++++++ 2 files changed, 39 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..cecaddb644ce 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 +149,24 @@ 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()) { + if (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);