From patchwork Fri Apr 4 13:23:40 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14038493 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 54FECC36010 for ; Fri, 4 Apr 2025 13:41:46 +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=QBP1kbX+rTZATJpmbS1r11O0Ao784tAFLxNhCqCbeG4=; b=SKT/oMF7tjkbAj/5MAvEF/ocos sp3tFbM3K2TV2LDKT3rBCqOO/3EORnWQPpdL1mJb0vD/3iw/uC2ovDpkZpJdJGz4CQGLt1dmYFAUA Wml6asYwftW9FT+qvXO+HevVCtBFYZKKVwESy64lXprYZSphEd4ohHUkEGBf3h6NF6JDTdYRFSwdL orF8ngoOZXDfX8YyraNSOoJnQJoFRAoSfiOOgdTeYGqDr5KZMUJ05eIJypFQzlLA5J6EkfVDl+rRm Gsu8XOr4io8OYLIVXZaNQyghPoMyaDLc7bRr/i1LhGfdFLFsStR22zwOHI12WJKSgreBSszoCwNUd IMA6jtNA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.1 #2 (Red Hat Linux)) id 1u0hId-0000000Brfa-1RGA; Fri, 04 Apr 2025 13:41:35 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.1 #2 (Red Hat Linux)) id 1u0h5L-0000000BpBa-3gQC for linux-arm-kernel@lists.infradead.org; Fri, 04 Apr 2025 13:27:53 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 0EE694505E; Fri, 4 Apr 2025 13:27:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 769E5C4CEDD; Fri, 4 Apr 2025 13:27:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743773271; bh=W0sT2qa3mBNAZifs1J2a+WxYpChdTdPcLwJokOzpIEo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=pw8M9lZVHewkcycpEec0qodr6bP7fZ/zpiF+ev1kIP9W0et2umUOU/NamJEWH6jOR e2R/N6BU4ISebVmQ9OjT8dUp19S4HM767oOSTjB642m16MecYN1WmL5IXweluivbZE t9kvI/0oLh0NZCYPKT1HNWpvQ3B2vOBiZKriZZtvN+FmtQX8dD3/sHF5r14Hp/8UTN KzoL27azh4h/fUYnH6VdvMpxaKOQuvnD+wf768hfU4zngKbXtzp4RvEI2jueEzldH/ u2ymiSMI1D41BjwVWaR7c4UdwbOzT+6mYraZLqPFTSahCPRTCTYRaPaBUG7h/M/gud wzxTC6ggGDFFg== From: Mark Brown Date: Fri, 04 Apr 2025 14:23:40 +0100 Subject: [PATCH RESEND 6.1 07/12] KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN MIME-Version: 1.0 Message-Id: <20250404-stable-sve-6-1-v1-7-cd5c9eb52d49@kernel.org> References: <20250404-stable-sve-6-1-v1-0-cd5c9eb52d49@kernel.org> In-Reply-To: <20250404-stable-sve-6-1-v1-0-cd5c9eb52d49@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , James Morse , Suzuki K Poulose , Oliver Upton , Oleg Nesterov , Greg Kroah-Hartman Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu, Mark Brown , stable@vger.kernel.org, Mark Rutland , Fuad Tabba X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=3522; i=broonie@kernel.org; h=from:subject:message-id; bh=J/OoE8FnpyEkhPOOs7+baEyK/IhjSZTlC9a6+usk3TM=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBn794yD8xqXui9XonlLAg4gJEZgDxzTnNyUs2dj7fe Io10iKuJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ+/eMgAKCRAk1otyXVSH0IOYB/ sElUgNXACyCnoLY6IviOFiPWXT9uW1TDEK0HC/H/xKkC3NQt859TCHOq1e4s+ADhr4E89tALf0MOSQ N+kmSHjvkUqiTru0aJOxW31XWEHmyzzoF0hwEJtQ7ZAMhNMoooIYIg+ck/bQOTXEW8Io67yZ/AK6Mn IeyFmrtpp/ETP79o0ZYOcoNbqMmjPBMIcHauVuL0KcmvEOLIQ9kXCQ9TonoLCIl5s9qUwOUz8CMVFs xWd8KmJx2xhphMpj5v9R9vf66LmZpyKdbhJhm0j4n7BMa8KoOVFV9bYKr/y4BKar0DRik2hpyMSp15 ayyZUWeErJkGv7KATAcuZWIY+VqAB6 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-20250404_062751_961451_2BF6B9CC X-CRM114-Status: GOOD ( 17.20 ) 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 7f187ac24e5d..181e49120e0c 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 ee7c59f96451..8d073a37c266 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);