From mboxrd@z Thu Jan 1 00:00:00 1970 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 71C55C369D7 for ; Tue, 22 Apr 2025 07:08:09 +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:Content-Transfer-Encoding: Content-Type:MIME-Version:Message-ID:In-Reply-To:Date:From:Cc:To:Subject: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:References:List-Owner; bh=qFKFlqUchnVK8vXQTzoHWqGqQPJ712srblJDGiFjejw=; b=NDM0p53WxDIuJHoQItLCs8LJyC uMLNfKTpYPnCiomYnGBRjqyLiZjUkZNpz+n27PPgTePqMOgJLoJPb9L3WRbRIZLIvqbbVpiMSNB2J KI30FhqRJEgENA9N4NJze4i0iIXcMAoCBs7W3PR1pVXMGHIHlWw15qVYOJqBUJV2w0TgvY5T+/qbA m7YJeAAQ1WcJwYe3f9CL76Hmb0zUlqbXYwEYIlt4adWB8Ne29+Mf8IH0Xt6wMAcgdpskcBVidGxE+ 4FmcE1kCR9+4C58AQB1mBmJf2rZTLHLd4xDioYRM3byxdPUxb8N9AqZvHLeF8SL4mlihqNm3N1FmK Y++KQUDQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u77jY-000000064YZ-1ucr; Tue, 22 Apr 2025 07:07:56 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u77NG-000000061I9-0I54 for linux-arm-kernel@lists.infradead.org; Tue, 22 Apr 2025 06:44:54 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 9C9D06112C; Tue, 22 Apr 2025 06:44:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E1F0C4CEE9; Tue, 22 Apr 2025 06:44:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745304263; bh=/PnlOVIPFOW0Ywe4BvJhNHeadkLmRd1xoHAwVlkylnw=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=pRpXeJHtabiXIuWJ5SFDZtVGIXCeP8jkjjgSSs4bxY3K6hljmTc8YlCxlPNuATFWP zWEo6Z2oD6AjmSIzTqydb7+3Di25PuhgYzK8QMEmPWowSpzdJRLDGD46XWk29p49WM 9Q7keeWmnJWZQ5dilner6CHcoZavG7RkAbe+zAEs= Subject: Patch "KVM: arm64: Remove VHE host restore of CPACR_EL1.SMEN" has been added to the 6.1-stable tree To: broonie@kernel.org,catalin.marinas@arm.com,gregkh@linuxfoundation.org,james.morse@arm.com,kvmarm@lists.cs.columbia.edu,kvmarm@lists.linux.dev,linux-arm-kernel@lists.infradead.org,mark.rutland@arm.com,maz@kernel.org,oleg@redhat.com,oliver.upton@linux.dev,suzuki.poulose@arm.com,tabba@google.com,will@kernel.org Cc: From: Date: Tue, 22 Apr 2025 08:43:54 +0200 In-Reply-To: <20250404-stable-sve-6-1-v1-8-cd5c9eb52d49@kernel.org> Message-ID: <2025042254-manhood-irrigate-83c5@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit X-stable: commit X-Patchwork-Hint: ignore 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 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.SMEN to the 6.1-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.smen.patch and it can be found in the queue-6.1 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 Fri Apr 4 15:27:55 2025 From: Mark Brown Date: Fri, 04 Apr 2025 14:23:41 +0100 Subject: KVM: arm64: Remove VHE host restore of CPACR_EL1.SMEN 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 Message-ID: <20250404-stable-sve-6-1-v1-8-cd5c9eb52d49@kernel.org> From: Mark Rutland [ Upstream commit 407a99c4654e8ea65393f412c421a55cac539f5b ] When KVM is in VHE mode, the host kernel tries to save and restore the configuration of CPACR_EL1.SMEN (i.e. CPTR_EL2.SMEN 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 has historically been broken, and is currently redundant. This logic was originally introduced in commit: 861262ab86270206 ("KVM: arm64: Handle SME host state when running guests") At the time, the VHE hyp code would reset CPTR_EL2.SMEN to 0b00 when returning to the host, trapping host access to SME state. Unfortunately, this was unsafe as the host could take a softirq before calling kvm_arch_vcpu_put_fp(), and if a softirq handler were to use kernel mode NEON the resulting attempt to save the live FPSIMD/SVE/SME state would result in a fatal trap. That issue was limited to VHE mode. For nVHE/hVHE modes, KVM always saved/restored the host kernel's CPACR_EL1 value, and configured CPTR_EL2.TSM to 0b0, ensuring that host usage of SME would not be trapped. The issue above was incidentally fixed by commit: 375110ab51dec5dc ("KVM: arm64: Fix resetting SME trap values on reset for (h)VHE") That commit changed the VHE hyp code to configure CPTR_EL2.SMEN to 0b01 when returning to the host, permitting host kernel usage of SME, avoiding the issue described above. At the time, this was not identified as a fix for commit 861262ab86270206. 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 SME 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/20250210195226.1215254-5-mark.rutland@arm.com Signed-off-by: Marc Zyngier [Update for rework of flags storage -- 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 | 31 ------------------------------- 2 files changed, 33 deletions(-) --- 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)) -/* SME enabled for EL0 */ -#define HOST_SME_ENABLED __vcpu_single_flag(sflags, BIT(1)) /* Physical CPU not in supported_cpus */ #define ON_UNSUPPORTED_CPU __vcpu_single_flag(sflags, BIT(2)) /* WFIT instruction trapped */ --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -87,21 +87,6 @@ void kvm_arch_vcpu_load_fp(struct kvm_vc */ fpsimd_save_and_flush_cpu_state(); vcpu->arch.fp_state = FP_STATE_FREE; - - /* - * We don't currently support SME guests but if we leave - * things in streaming mode then when the guest starts running - * FPSIMD or SVE code it may generate SME traps so as a - * special case if we are in streaming mode we force the host - * state to be saved now and exit streaming mode so that we - * don't have to handle any SME traps for valid guest - * operations. Do this for ZA as well for now for simplicity. - */ - if (system_supports_sme()) { - vcpu_clear_flag(vcpu, HOST_SME_ENABLED); - if (read_sysreg(cpacr_el1) & CPACR_EL1_SMEN_EL0EN) - vcpu_set_flag(vcpu, HOST_SME_ENABLED); - } } /* @@ -162,22 +147,6 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcp local_irq_save(flags); - /* - * If we have VHE then the Hyp code will reset CPACR_EL1 to - * CPACR_EL1_DEFAULT and we need to reenable SME. - */ - if (has_vhe() && system_supports_sme()) { - /* Also restore EL0 state seen on entry */ - if (vcpu_get_flag(vcpu, HOST_SME_ENABLED)) - sysreg_clear_set(CPACR_EL1, 0, - CPACR_EL1_SMEN_EL0EN | - CPACR_EL1_SMEN_EL1EN); - else - sysreg_clear_set(CPACR_EL1, - CPACR_EL1_SMEN_EL0EN, - CPACR_EL1_SMEN_EL1EN); - } - if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) { if (vcpu_has_sve(vcpu)) { __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR); Patches currently in stable-queue which might be from broonie@kernel.org are queue-6.1/kvm-arm64-remove-host-fpsimd-saving-for-non-protected-kvm.patch queue-6.1/spi-cadence-qspi-fix-probe-on-am62a-lp-sk.patch queue-6.1/asoc-qdsp6-q6asm-dai-fix-q6asm_dai_compr_set_params-error-path.patch queue-6.1/asoc-qdsp6-q6apm-dai-fix-capture-pipeline-overruns.patch queue-6.1/kvm-arm64-mark-some-header-functions-as-inline.patch queue-6.1/kvm-arm64-eagerly-switch-zcr_el-1-2.patch queue-6.1/kvm-arm64-unconditionally-save-flush-host-fpsimd-sve-sme-state.patch queue-6.1/asoc-amd-add-dmi-quirk-for-acp6x-mic-support.patch queue-6.1/kvm-arm64-refactor-exit-handlers.patch queue-6.1/asoc-qdsp6-q6apm-dai-set-10-ms-period-and-buffer-alignment.patch queue-6.1/asoc-codecs-lpass-wsa-macro-fix-vi-feedback-rate.patch queue-6.1/arm64-fpsimd-track-the-saved-fpsimd-state-type-separately-to-tif_sve.patch queue-6.1/kvm-arm64-remove-vhe-host-restore-of-cpacr_el1.zen.patch queue-6.1/kvm-arm64-remove-vhe-host-restore-of-cpacr_el1.smen.patch queue-6.1/asoc-fsl_audmix-register-card-device-depends-on-dais.patch queue-6.1/arm64-fpsimd-have-kvm-explicitly-say-which-fp-registers-to-save.patch queue-6.1/kvm-arm64-discard-any-sve-state-when-entering-kvm-guests.patch queue-6.1/arm64-fpsimd-stop-using-tif_sve-to-manage-register-saving-in-kvm.patch queue-6.1/asoc-codecs-lpass-wsa-macro-fix-logic-of-enabling-vi-channels.patch queue-6.1/kvm-arm64-calculate-cptr_el2-traps-on-activating-traps.patch