From patchwork Fri Mar 21 00:13:00 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14024729 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 19BC1C28B30 for ; Fri, 21 Mar 2025 00:35:06 +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=EwaytSZcMYBwN2yyzK/eik3WXF8jRnhZejv6/C/segI=; b=qZZqo6/gMNrExLNJabgoFrJW/g VaLoz0FI67edAdqp1sWbeGhhdSQIxyhkzxST6HwQMtk9HkAMV6v656BoZwVzonXriTNMb6s2tKKNV h4u013mNgGkecTVkbvbdGh0zAWupV1NpIJ8khj1FzO41Lmm26iJGFD1VGQcw/wT5lTrVmDmWd0UmA DJmHEXUVgLK6yeUV3cn7xSIN1zq0O4bgN+o5oMddBsJvfvPZGp7M0p2PTWgbMbMFyWh3NSCoPfcNB 17e2tjjE8DGsQ0daHORPKxhBx9ZUTV0HEuCw9Jde23ZWwJcGRoQe6tL4151EWronWrDG+1MbAbw+n kB24rEFA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tvQLg-0000000DZEL-0lPz; Fri, 21 Mar 2025 00:34:56 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tvQ18-0000000DWl0-0NnR for linux-arm-kernel@lists.infradead.org; Fri, 21 Mar 2025 00:13:43 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 86CB75C67F3; Fri, 21 Mar 2025 00:11:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFD67C4CEEA; Fri, 21 Mar 2025 00:13:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742516021; bh=4+mYHr6XrwTcEyqTdBUleqRnti7WbSWNsKz630OxK1Q=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=qUqoFkwPtJKV1nNAsfEoSOjAK0Mu92A/YhMajLmr2OQKgAgdVtSsLjPi8b7V6Xv7C FN570WpyKRVWVhraGNpdIwINXl+Y6QrA1EsQ452+OC7OhIh2HoHygma7mzgDKUXWCs 2DXE9JRWR07PavInjYlhCvrRHtQh98mg5CeJzJV5v/IX6NHWAtXP0JFTZkU0mGhDsZ YiKfa2bZ7hjtFsMxIGZiGeAeFbujFuSFvb5HxZyAHZ+Hln+2F/rD4Zceo5OqkV7DQi 0e+enLjxw+spZ4Pmy2btQOQl7KjENCS13ATmi6Ysju/deNIrU0uR9n7Ara9P7eovz+ agFI0RXepoesQ== From: Mark Brown Date: Fri, 21 Mar 2025 00:13:00 +0000 Subject: [PATCH 6.12 v2 4/8] KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN MIME-Version: 1.0 Message-Id: <20250321-stable-sve-6-12-v2-4-417ca2278d18@kernel.org> References: <20250321-stable-sve-6-12-v2-0-417ca2278d18@kernel.org> In-Reply-To: <20250321-stable-sve-6-12-v2-0-417ca2278d18@kernel.org> To: Greg Kroah-Hartman , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Mark Brown , Mark Rutland , Fuad Tabba X-Mailer: b4 0.15-dev-1b0d6 X-Developer-Signature: v=1; a=openpgp-sha256; l=3661; i=broonie@kernel.org; h=from:subject:message-id; bh=IG25WLsxwjh6t3HKhjHMAeq/c25F13vYeIg5ZhI8+KE=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBn3K8gaiSB2ODiSSpQdOlTSeteE0rnfj6LBVH7SVNq iakd6LuJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ9yvIAAKCRAk1otyXVSH0NpWB/ 44M16CBvchiG+Rp8njF7R9zpiUBPT2XnopdzSTZRIndVwGB2oA6rEkrtTwZQej+g+Uw0wSJ7VyxJn9 zwa8OAb8/Xz/bMcvJcRxe5qtvLAVtdkzTZkgKEYNXZutJ+BVOcnvRtotKLlHgCDH6zB4X4WdFuwqdF p9oj6iT3wNBbc1Hf9kyowKg2hcWmscL6Qv3HMiykjY1sVkqR4yM9Lt29P04nsfcglC4zx85uYi73dU FnjjET4r0Hh+QC9A3deG8NjJS7DoqCCL9SxezzPZV7YVrIyS8vtQ9HSK0dI3N7FSFziiYtGFNG0mvE Iiy8NnmLn1suoIF5kgQHGmv8PgPcnd 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-20250320_171342_223394_5C6CDBAC X-CRM114-Status: GOOD ( 17.25 ) 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 d8802490b25cba65369f03d94627a2624f14b072..1a126fa657fcde3433f37f3aaf464a5b6a5f095d 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -891,8 +891,6 @@ 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 2ee6bde85235581d6bc9cba7e578c55875b5d5a1..4127abfd319c2c683d2281efa52a6abe5fac67ee 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -65,10 +65,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) fpsimd_save_and_flush_cpu_state(); *host_data_ptr(fp_owner) = 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); - if (system_supports_sme()) { vcpu_clear_flag(vcpu, HOST_SME_ENABLED); if (read_sysreg(cpacr_el1) & CPACR_EL1_SMEN_EL0EN) @@ -202,18 +198,6 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) * when needed. */ 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 by kvm_reset_cptr_el2() in 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);