From patchwork Fri Mar 21 00:16:04 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 14024738 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 27866C28B30 for ; Fri, 21 Mar 2025 00:50:41 +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=0e+mUjDAWf3s0YKL6KQvH3NwIpYY0unoMYXfb9E1b+g=; b=XKs2au3Cx4trO6Pw8l4l3L9Gqi 9eMMhDCsiOwGibCyVID7DAfGcs6Z3jQdBH5v8byP0n8Ts0MKHuvuytnwORQ745r54xU69f63t2+Km rCCMjncUkV4sg3iuJP6Rkwd6eguFlDkO4K01EDXzL0upFw3gH42MCR/JRbMBILf9JQvd8j1TGka+p Zm7eiV/I/NZnWB+wjKweBHt0S3ufwYfxp5R8DFw7hhhEUagQR4wpcX4ppkYgPgsjI9cOH19OGHm85 ox6AB5hGR6trJ4KG0lJBa6X9a/ziZ0jTGcpzrLkmth5BHe7tUEtQwped7vW9yVnXYBtX9mf9G4AOF omsB/J4w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tvQai-0000000DapP-433Y; Fri, 21 Mar 2025 00:50:28 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tvQ5k-0000000DXV5-3dyW for linux-arm-kernel@lists.infradead.org; Fri, 21 Mar 2025 00:18:30 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 4AEA25C6820; Fri, 21 Mar 2025 00:16:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85AE3C4CEDD; Fri, 21 Mar 2025 00:18:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742516308; bh=CFBkZ3D3qqKor5Kj9cL5tM3zTXoy9Y0nRxvtgtnhaUQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=pIVATjvSPxV7eaF1uh1SB3g2F3VirR4rPbKKUZnzb+gD8uIISrkYKbRDHG6ujaOv0 Coqp+rN5bUMGgY4EEAdIoXSt3qkvcZ82q3TLLdsmlG8DgJhNrGs7D53PwxiAtO8Ss1 e0sU24+C3MRPDkz7YZo1m6A9x6rZpmIBPj8G+UGacbTSCKnaAhjJgMVrCW9xl1Te6F Gv1UHwVhr6Tp2Q8KxQeZ++thAAHOb1LumHpZc7sCQLnGisiw8be1WmdWJbYG6mbzgh PtX7nNY2KZAIy5L5VMwIwSjxhPUg+QsenQp2Gr8n8HkwOueDkDxQEfZl6B46HVr+F2 E9kb27/LopShA== From: Mark Brown Date: Fri, 21 Mar 2025 00:16:04 +0000 Subject: [PATCH 6.6 4/8] KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN MIME-Version: 1.0 Message-Id: <20250321-stable-sve-6-6-v1-4-0b3a6a14ea53@kernel.org> References: <20250321-stable-sve-6-6-v1-0-0b3a6a14ea53@kernel.org> In-Reply-To: <20250321-stable-sve-6-6-v1-0-0b3a6a14ea53@kernel.org> To: Greg Kroah-Hartman , Marc Zyngier , Oliver Upton , James Morse , 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=3631; i=broonie@kernel.org; h=from:subject:message-id; bh=bEhjaWWeo3MZO4hv+4A0+U6DdeP5Zvjor/41KIDmUy4=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBn3LA9h7iGC6z3d780UO9FNjZjJlZmARitK1wAo5KK CyUCMcmJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ9ywPQAKCRAk1otyXVSH0CueCA CCr8ZNxeoYBGooYidPdc4468iwsk8Q3DIHQHwgFNO/Wa9FS57xkTpMSZFsBJEhksiGasBeDTcQMOQV YfDj4w8ImQclIvmXq/WPHewaesljGxLjGaHGCapiX5XpVeXJTuHvG5IP/2/dK2WKPcUTsoxZ0f7wm7 awdhgw+iZA/ntG3LSKmP7LP83HyzQ1CE6xyBu/r/NVW0zgv5tr22bRdd2qKKivuK0SPsdUKS8RUjDl mW4suwnCmYV56lizBnBYD0+AX5hYR/KuDL8KDBFUUYOnjCAgohQIBS7Tzz762mKkOTVUrqfqygl8VZ xr8T/jywDbQDXm7I7bOj3HMe0KnvVN 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_171829_021067_A3594C93 X-CRM114-Status: GOOD ( 17.35 ) 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 3891963d42e00c8f999886dc5d7322bbacbc6c7f..9c1056d6f6859522dcee4b8c4e4804a7abac93d5 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -717,8 +717,6 @@ struct kvm_vcpu_arch { /* vcpu running in HYP context */ #define VCPU_HYP_CONTEXT __vcpu_single_flag(iflags, BIT(7)) -/* 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 7c36d2a7aa3196056f76acfe8f9c41763ed67d9d..f1fe7abbcb83393e7c3402405bb7b1fdbf6024ff 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); - if (system_supports_sme()) { vcpu_clear_flag(vcpu, HOST_SME_ENABLED); if (read_sysreg(cpacr_el1) & CPACR_EL1_SMEN_EL0EN) @@ -189,18 +185,6 @@ 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 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);