From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E72AB254866; Tue, 25 Mar 2025 11:30:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742902235; cv=none; b=kvxtLhJ7r+wr5jX+l+mvnjJd8RDiLuNKFmW0cmWZlNp0l3hypxZ6j3LYeYV/E1uNdfxrFpqkvV/lMDMX4ifpCmqM63yQ/Ip8RwqaYkfAh7TaTWptRMYr29KGVcUYz+rNwWk0L1aOXhMugswyzW2bQE47ughNmNAt15LVULE84tE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742902235; c=relaxed/simple; bh=9p26Ucq76mncIc0Qr9yGm+jGQhnsiQsxzsXsY8XHLk4=; h=Subject:To:Cc:From:Date:In-Reply-To:Message-ID:MIME-Version: Content-Type; b=ZaUKUvEv0z7od3xEmqrj0eCSlX/OBYIDP5MaK6naFNBhk3NW7ik5ha0ZIuvL+vtn9jrdyQXogeH4ZtqPR8P8RY4t/LOrU2J5qcqI8pvBIKWcFgQD8yMaX8+7417PEo90bXcuMWKAWgoAMcQzQ64NPYLqlMMnrlcz2HCFKYwFy5Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GCfmhugf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GCfmhugf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38894C4CEE4; Tue, 25 Mar 2025 11:30:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1742902234; bh=9p26Ucq76mncIc0Qr9yGm+jGQhnsiQsxzsXsY8XHLk4=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=GCfmhugf2Q67WeyCMPzmWxsqKa44FcpnwK085Jcg0PBshwht+NRLtjIZ4MK7MoqqT gfotgnRCe4AOtAwN6wIEgXVzB+LSxIG8Wh8WYx+jqaiWwwoU9CYtpv8505UbkCeVss lcgL565YtO/qkNHv0AGQfT45z4MuPwJjvwbkLavw= Subject: Patch "KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN" has been added to the 6.6-stable tree To: broonie@kernel.org,catalin.marinas@arm.com,gregkh@linuxfoundation.org,james.morse@arm.com,kvmarm@lists.linux.dev,linux-arm-kernel@lists.infradead.org,mark.rutland@arm.com,maz@kernel.org,oliver.upton@linux.dev,suzuki.poulose@arm.com,tabba@google.com,will@kernel.org Cc: From: Date: Tue, 25 Mar 2025 07:28:56 -0400 In-Reply-To: <20250321-stable-sve-6-6-v1-4-0b3a6a14ea53@kernel.org> Message-ID: <2025032556-docile-unknowing-7dec@gregkh> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore This is a note to let you know that I've just added the patch titled KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kvm-arm64-remove-vhe-host-restore-of-cpacr_el1.zen.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From broonie@kernel.org Thu Mar 20 20:18:28 2025 From: Mark Brown Date: Fri, 21 Mar 2025 00:16:04 +0000 Subject: KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN 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 Message-ID: <20250321-stable-sve-6-6-v1-4-0b3a6a14ea53@kernel.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 Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/kvm_host.h | 2 -- arch/arm64/kvm/fpsimd.c | 16 ---------------- 2 files changed, 18 deletions(-) --- 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 */ --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -88,10 +88,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vc 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_vcp } 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); Patches currently in stable-queue which might be from broonie@kernel.org are queue-6.6/kvm-arm64-calculate-cptr_el2-traps-on-activating-traps.patch queue-6.6/regulator-check-that-dummy-regulator-has-been-probed-before-using-it.patch queue-6.6/kvm-arm64-eagerly-switch-zcr_el-1-2.patch queue-6.6/kvm-arm64-mark-some-header-functions-as-inline.patch queue-6.6/kvm-arm64-remove-host-fpsimd-saving-for-non-protected-kvm.patch queue-6.6/regulator-dummy-force-synchronous-probing.patch queue-6.6/kvm-arm64-refactor-exit-handlers.patch queue-6.6/kvm-arm64-unconditionally-save-flush-host-fpsimd-sve-sme-state.patch queue-6.6/kvm-arm64-remove-vhe-host-restore-of-cpacr_el1.smen.patch queue-6.6/kvm-arm64-remove-vhe-host-restore-of-cpacr_el1.zen.patch