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 30C0DC369C2 for ; Tue, 22 Apr 2025 07:27:09 +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=OhjMBLNeMDO3uJ93DVTKdFy+XBxJfXI1TdN+ktOOWcI=; b=sUAfKVjVX5Y20v3MkvnJ961gOn WNUQ7CpwPRmn9aB4B/dCI5YwelueU7sKdHwKfS1W1H5OMEG5iglC1ta1/qItfXnSryzZlKQxzzvac uiRlBtI0AjcxskkcqXy0UoUxKkOdNo68D1zgwTP0zM3slmj5SwDQdAu2c//EjMWcHgFJFeGjg2iUl UBYwS7DV++nX7D5GQAgTMbkymCu0LC+Prfi+YVuncKGt7tlz7GSRg/owqN8KFWqLibIIl06dbk7hU 31xd0LXmsTf+SPG6oMs8PAqVv7OLFGy9AeqkFEEeEuzeAYOJ2km0tjf1/2LN10a5+7z/Ue6rAvllE B+tadnzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u781y-0000000676n-46DK; Tue, 22 Apr 2025 07:26:58 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u77O6-000000061Wu-1k2c for linux-arm-kernel@lists.infradead.org; Tue, 22 Apr 2025 06:45:47 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 96E4CA4BCCB; Tue, 22 Apr 2025 06:40:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 169BBC4CEE9; Tue, 22 Apr 2025 06:45:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745304345; bh=Rri21VOEYDniTPNhyTjMinUkbx1j8ejG15dMonehiZc=; h=Subject:To:Cc:From:Date:In-Reply-To:From; b=Wrs3MCg6hojnuAhuSiIXg3fn0YsEJEvuZ2gTuRzQ/2n3ppouTWqlxzDJr9JAS/Gbc e10H8/oA/GWjUNjC+J4Q1bKkWQKFB3F5tgaoE5FshuZzJ8RtyagqwqwiGBjwv+O5+A /SRZBOpcwBJh++QGoGxiLp3+IAmjw9S9Txq4TNCc= Subject: Patch "KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state" has been added to the 5.15-stable tree To: broonie@kernel.org,catalin.marinas@arm.com,eauger@redhat.com,eric.auger@redhat.com,fweimer@redhat.com,gregkh@linuxfoundation.org,james.morse@arm.com,jeremy.linton@arm.com,kvmarm@lists.cs.columbia.edu,linux-arm-kernel@lists.infradead.org,mark.rutland@arm.com,maz@kernel.org,oleg@redhat.com,oliver.upton@linux.dev,pbonzini@redhat.com,suzuki.poulose@arm.com,tabba@google.com,wilco.dijkstra@arm.com,will@kernel.org Cc: From: Date: Tue, 22 Apr 2025 08:45:14 +0200 In-Reply-To: <20250408-stable-sve-5-15-v3-7-ca9a6b850f55@kernel.org> Message-ID: <2025042214-mute-deodorize-2a01@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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250421_234546_591012_B7374A80 X-CRM114-Status: GOOD ( 26.70 ) 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: Unconditionally save+flush host FPSIMD/SVE/SME state to the 5.15-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-unconditionally-save-flush-host-fpsimd-sve-sme-state.patch and it can be found in the queue-5.15 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 Tue Apr 8 20:22:40 2025 From: Mark Brown Date: Tue, 08 Apr 2025 19:10:02 +0100 Subject: KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state To: Greg Kroah-Hartman , Marc Zyngier , James Morse , Suzuki K Poulose , Catalin Marinas , Will Deacon , Oleg Nesterov , Oliver Upton Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Mark Brown , Mark Rutland , Eric Auger , Wilco Dijkstra , Eric Auger , Florian Weimer , Fuad Tabba , Jeremy Linton , Paolo Bonzini Message-ID: <20250408-stable-sve-5-15-v3-7-ca9a6b850f55@kernel.org> From: Mark Rutland [ Upstream commit fbc7e61195e23f744814e78524b73b59faa54ab4 ] There are several problems with the way hyp code lazily saves the host's FPSIMD/SVE state, including: * Host SVE being discarded unexpectedly due to inconsistent configuration of TIF_SVE and CPACR_ELx.ZEN. This has been seen to result in QEMU crashes where SVE is used by memmove(), as reported by Eric Auger: https://issues.redhat.com/browse/RHEL-68997 * Host SVE state is discarded *after* modification by ptrace, which was an unintentional ptrace ABI change introduced with lazy discarding of SVE state. * The host FPMR value can be discarded when running a non-protected VM, where FPMR support is not exposed to a VM, and that VM uses FPSIMD/SVE. In these cases the hyp code does not save the host's FPMR before unbinding the host's FPSIMD/SVE/SME state, leaving a stale value in memory. Avoid these by eagerly saving and "flushing" the host's FPSIMD/SVE/SME state when loading a vCPU such that KVM does not need to save any of the host's FPSIMD/SVE/SME state. For clarity, fpsimd_kvm_prepare() is removed and the necessary call to fpsimd_save_and_flush_cpu_state() is placed in kvm_arch_vcpu_load_fp(). As 'fpsimd_state' and 'fpmr_ptr' should not be used, they are set to NULL; all uses of these will be removed in subsequent patches. Historical problems go back at least as far as v5.17, e.g. erroneous assumptions about TIF_SVE being clear in commit: 8383741ab2e773a9 ("KVM: arm64: Get rid of host SVE tracking/saving") ... and so this eager save+flush probably needs to be backported to ALL stable trees. Fixes: 93ae6b01bafee8fa ("KVM: arm64: Discard any SVE state when entering KVM guests") Fixes: 8c845e2731041f0f ("arm64/sve: Leave SVE enabled on syscall if we don't context switch") Fixes: ef3be86021c3bdf3 ("KVM: arm64: Add save/restore support for FPMR") Reported-by: Eric Auger Reported-by: Wilco Dijkstra Reviewed-by: Mark Brown Tested-by: Mark Brown Tested-by: Eric Auger Acked-by: Will Deacon Cc: Catalin Marinas Cc: Florian Weimer Cc: Fuad Tabba Cc: Jeremy Linton Cc: Marc Zyngier Cc: Oliver Upton Cc: Paolo Bonzini Signed-off-by: Mark Rutland Reviewed-by: Oliver Upton Link: https://lore.kernel.org/r/20250210195226.1215254-2-mark.rutland@arm.com Signed-off-by: Marc Zyngier [ Mark: Handle vcpu/host flag conflict, remove host_data_ptr() ] Signed-off-by: Mark Rutland Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/fpsimd.c | 25 ------------------------- arch/arm64/kvm/fpsimd.c | 13 ++++++++++--- 2 files changed, 10 insertions(+), 28 deletions(-) --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1155,31 +1155,6 @@ void fpsimd_signal_preserve_current_stat } /* - * Called by KVM when entering the guest. - */ -void fpsimd_kvm_prepare(void) -{ - if (!system_supports_sve()) - return; - - /* - * KVM does not save host SVE state since we can only enter - * the guest from a syscall so the ABI means that only the - * non-saved SVE state needs to be saved. If we have left - * SVE enabled for performance reasons then update the task - * state to be FPSIMD only. - */ - get_cpu_fpsimd_context(); - - if (test_and_clear_thread_flag(TIF_SVE)) { - sve_to_fpsimd(current); - current->thread.fp_type = FP_STATE_FPSIMD; - } - - put_cpu_fpsimd_context(); -} - -/* * Associate current's FPSIMD context with this cpu * The caller must have ownership of the cpu FPSIMD context before calling * this function. --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -74,9 +74,16 @@ void kvm_arch_vcpu_load_fp(struct kvm_vc vcpu->arch.flags &= ~KVM_ARM64_FP_ENABLED; vcpu->arch.flags |= KVM_ARM64_FP_HOST; - fpsimd_kvm_prepare(); - - vcpu->arch.flags &= ~KVM_ARM64_HOST_SVE_ENABLED; + /* + * Ensure that any host FPSIMD/SVE/SME state is saved and unbound such + * that the host kernel is responsible for restoring this state upon + * return to userspace, and the hyp code doesn't need to save anything. + * + * When the host may use SME, fpsimd_save_and_flush_cpu_state() ensures + * that PSTATE.{SM,ZA} == {0,0}. + */ + fpsimd_save_and_flush_cpu_state(); + vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN) vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED; Patches currently in stable-queue which might be from broonie@kernel.org are queue-5.15/kvm-arm64-remove-host-fpsimd-saving-for-non-protected-kvm.patch queue-5.15/spi-cadence-qspi-fix-probe-on-am62a-lp-sk.patch queue-5.15/asoc-qdsp6-q6asm-dai-fix-q6asm_dai_compr_set_params-error-path.patch queue-5.15/kvm-arm64-eagerly-switch-zcr_el-1-2.patch queue-5.15/kvm-arm64-unconditionally-save-flush-host-fpsimd-sve-sme-state.patch queue-5.15/kvm-arm64-always-start-with-clearing-sve-flag-on-load.patch queue-5.15/asoc-codecs-lpass-wsa-macro-fix-vi-feedback-rate.patch queue-5.15/arm64-fpsimd-track-the-saved-fpsimd-state-type-separately-to-tif_sve.patch queue-5.15/kvm-arm64-get-rid-of-host-sve-tracking-saving.patch queue-5.15/kvm-arm64-remove-vhe-host-restore-of-cpacr_el1.zen.patch queue-5.15/asoc-fsl_audmix-register-card-device-depends-on-dais.patch queue-5.15/arm64-fpsimd-have-kvm-explicitly-say-which-fp-registers-to-save.patch queue-5.15/kvm-arm64-discard-any-sve-state-when-entering-kvm-guests.patch queue-5.15/arm64-fpsimd-stop-using-tif_sve-to-manage-register-saving-in-kvm.patch queue-5.15/asoc-codecs-lpass-wsa-macro-fix-logic-of-enabling-vi-channels.patch queue-5.15/kvm-arm64-calculate-cptr_el2-traps-on-activating-traps.patch