From patchwork Tue Mar 25 18:48:21 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14029384 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4CF69C36008 for ; Tue, 25 Mar 2025 19:02:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=N85DK1p2wzpfx1u0ZJE/gFvmj0hhOdS7vgibxmt0O40=; b=MkG5EFas2L3KGCEJBwfXU3Brfs ksPFYU3PQycwn7tpFH6/rxnbNjY92mfybwUvbKtjgqwbXIdu/Si/pfKvYrDh9i7NfRbf15o8e3x0i ZA0IRcabeLKmEgVtrsX+a1l6OBZrFEvUdtEFmMrG4vAXogeax7iR/iwoA4yhDwqFgHn+WMFmUpSdb Ne2umw22vv0/wdSkGqmrofxJElbYoJdkC8LVhfEhfvkHbhnkuHtUV5ocZ/m88RUNjDaLoVaBa53gq L4yFBrg1VUxK6D1MmnM3NwzdTyhjH1GnLClXSqnl286Lh5+RmByPQFETKo6TAPTT6HcB11S5SFNrZ b4T7kFcg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.1 #2 (Red Hat Linux)) id 1tx9XE-00000006npX-03ao; Tue, 25 Mar 2025 19:02:00 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.98.1 #2 (Red Hat Linux)) id 1tx9LO-00000006lVZ-1ybJ for linux-arm-kernel@lists.infradead.org; Tue, 25 Mar 2025 18:49:47 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id D8EE65C6445; Tue, 25 Mar 2025 18:47:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20812C4CEED; Tue, 25 Mar 2025 18:49:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742928585; bh=X5eRhBQLAggts9ERTWvr9rKEs2alPOTSWgD7OqqZIN8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Odzualcxu/qX7u8PpzHKzqSmdt2x2SbNJefG/Q/K0ZqA8E06uTRVfGKX24tzd02sr yl9nenkN+SPgf71jDsqe/FP7sMKIoLTyosNc8rmDj+MZmmJxi5ezwSxGSxVhuIo2PC ZChr/b5kIbWgFpqYEOfJ0cI8qMpYrQMYF+iCWeJof6xwZk/zx+JJEjpzQvkXjXhyEr orEGfkkbB3PLO5ty4tJN2ww/KcDFoD1WblJHk9hXPLz8gPAfI8o+U6Ed9ojeQBdjFH eM6gpEGxzvzSsxikrxWEerYEFmDtTfBxiSFE7igXsdE9UWSr6d01OT/DkjzmS60AV8 HGyJKB41rxQJw== From: Mark Brown Date: Tue, 25 Mar 2025 18:48:21 +0000 Subject: [PATCH 6.1 07/12] KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN MIME-Version: 1.0 Message-Id: <20250325-stable-sve-6-1-v1-7-83259d427d84@kernel.org> References: <20250325-stable-sve-6-1-v1-0-83259d427d84@kernel.org> In-Reply-To: <20250325-stable-sve-6-1-v1-0-83259d427d84@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , James Morse , Suzuki K Poulose , Oliver Upton , Oleg Nesterov Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, Mark Brown , Mark Rutland , Fuad Tabba X-Mailer: b4 0.15-dev-1b0d6 X-Developer-Signature: v=1; a=openpgp-sha256; l=3634; i=broonie@kernel.org; h=from:subject:message-id; bh=C/AXsrfE3hDPJKqhIkQ1xaGMTu2EikC8eGqDGNKSWKI=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBn4vqrsF4AEeGTms53DWRq+132vria4s0fh51zggoX R/R94PWJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ+L6qwAKCRAk1otyXVSH0LgSB/ 4qWD69N3mAaQCA9Z4f120o/aQUF6nk0yYQnor/+nrwgIUuqzoh1mVDLeAIEN6+jFCJWOQGVNB3KxDp NvkR95EUYqO+CvOKH3r3KHt1/psRcF2AtN5i3wSvdDvkua/AjBxrELcvibBgCkeLOXvHs6e6ce9dQ9 mKL+QKaPzdjG0gEhpWJwTJ3GPMVxzmjNYwKx33BA8nZjFGyb5IzEhizRDC1VqO5UktNLFy/G/tjM9o CNO/+2e1JypF/Vy+XsQqVzULqZLMzD34hWXw01P8GSWmQyhATnSGc1GOM/AKIPZUpAm8qftdUnmL3n 2hE0hkzCAwbVzAjP5k3cvPGuLICGbT X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250325_114946_628685_A6F12152 X-CRM114-Status: GOOD ( 17.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Mark Rutland [ Upstream commit 459f059be702056d91537b99a129994aa6ccdd35 ] When KVM is in VHE mode, the host kernel tries to save and restore the configuration of CPACR_EL1.ZEN (i.e. CPTR_EL2.ZEN when HCR_EL2.E2H=1) across kvm_arch_vcpu_load_fp() and kvm_arch_vcpu_put_fp(), since the configuration may be clobbered by hyp when running a vCPU. This logic is currently redundant. The VHE hyp code unconditionally configures CPTR_EL2.ZEN to 0b01 when returning to the host, permitting host kernel usage of SVE. Now that the host eagerly saves and unbinds its own FPSIMD/SVE/SME state, there's no need to save/restore the state of the EL0 SVE trap. The kernel can safely save/restore state without trapping, as described above, and will restore userspace state (including trap controls) before returning to userspace. Remove the redundant logic. Signed-off-by: Mark Rutland Reviewed-by: Mark Brown Tested-by: Mark Brown Acked-by: Will Deacon Cc: Catalin Marinas Cc: Fuad Tabba Cc: Marc Zyngier Cc: Oliver Upton Reviewed-by: Oliver Upton Link: https://lore.kernel.org/r/20250210195226.1215254-4-mark.rutland@arm.com Signed-off-by: Marc Zyngier [Rework for refactoring of where the flags are stored -- broonie] Signed-off-by: Mark Brown --- arch/arm64/include/asm/kvm_host.h | 2 -- arch/arm64/kvm/fpsimd.c | 16 ---------------- 2 files changed, 18 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7f187ac24e5d37369ef0af4154fdb17890f28798..181e49120e0c4027aa52dd389de13f9ce5cd7b57 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -556,8 +556,6 @@ struct kvm_vcpu_arch { /* Save TRBE context if active */ #define DEBUG_STATE_SAVE_TRBE __vcpu_single_flag(iflags, BIT(6)) -/* SVE enabled for host EL0 */ -#define HOST_SVE_ENABLED __vcpu_single_flag(sflags, BIT(0)) /* SME enabled for EL0 */ #define HOST_SME_ENABLED __vcpu_single_flag(sflags, BIT(1)) /* Physical CPU not in supported_cpus */ diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index ee7c59f96451fcb217957c9fdbbd76046393bef3..8d073a37c266db3dc2726c6a0bb39c7e2586f53f 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -88,10 +88,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) fpsimd_save_and_flush_cpu_state(); vcpu->arch.fp_state = FP_STATE_FREE; - vcpu_clear_flag(vcpu, HOST_SVE_ENABLED); - if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN) - vcpu_set_flag(vcpu, HOST_SVE_ENABLED); - /* * We don't currently support SME guests but if we leave * things in streaming mode then when the guest starts running @@ -193,18 +189,6 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) } fpsimd_save_and_flush_cpu_state(); - } else if (has_vhe() && system_supports_sve()) { - /* - * The FPSIMD/SVE state in the CPU has not been touched, and we - * have SVE (and VHE): CPACR_EL1 (alias CPTR_EL2) has been - * reset to CPACR_EL1_DEFAULT by the Hyp code, disabling SVE - * for EL0. To avoid spurious traps, restore the trap state - * seen by kvm_arch_vcpu_load_fp(): - */ - if (vcpu_get_flag(vcpu, HOST_SVE_ENABLED)) - sysreg_clear_set(CPACR_EL1, 0, CPACR_EL1_ZEN_EL0EN); - else - sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0); } local_irq_restore(flags);