From patchwork Mon Feb 10 19:52:18 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13969075 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 01B4DC02198 for ; Mon, 10 Feb 2025 19:54:19 +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: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=YcfQoattcfAtqhYK+I0xVSz5YvJgMhhlIZULFz+ZEuM=; b=DSzFJS99iUV3kP/rvTsObcO2pW H1xZPMRVCkb0PTBhrgznxTUYD1MkzxnlOsM6Lj50k5GS6mdJcDBdjqPxapmAy10BCZf3H3OogIJ3d k40wUBI19ZmWh4akght21Qs9WDgIadug4CdWVEb+peyPr9OaF2xq+Yw9Gs8b9k1TdQH4KLJmwgT+8 +WWoJRgjASkLwFkKL/DXlkIhACKVd7eyoSVzb5LBmO7ErpN1bQWp5hzP80771aH9GJG7esMCaj2GU 7yFMJRt+jyS1shWIPYW5USjA2Q/VYDYOu04hRwn4cYGe8G1F4U1EJ9qAsSlA0kHSUlMPrevjgh3Zj I/wLUBYg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1thZr7-00000001EtT-1Dsb; Mon, 10 Feb 2025 19:54:09 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1thZpf-00000001EXm-210y for linux-arm-kernel@lists.infradead.org; Mon, 10 Feb 2025 19:52:41 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C86591477; Mon, 10 Feb 2025 11:52:57 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id EA34C3F58B; Mon, 10 Feb 2025 11:52:32 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: broonie@kernel.org, catalin.marinas@arm.com, eauger@redhat.com, eric.auger@redhat.com, fweimer@redhat.com, jeremy.linton@arm.com, mark.rutland@arm.com, maz@kernel.org, oliver.upton@linux.dev, pbonzini@redhat.com, stable@vger.kernel.org, tabba@google.com, wilco.dijkstra@arm.com, will@kernel.org Subject: [PATCH v3 0/8] KVM: arm64: FPSIMD/SVE/SME fixes Date: Mon, 10 Feb 2025 19:52:18 +0000 Message-Id: <20250210195226.1215254-1-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250210_115239_603539_4C9A6D1F X-CRM114-Status: GOOD ( 12.56 ) 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 These patches fix some issues with the way KVM manages FPSIMD/SVE/SME state. The series supersedes my earlier attempt at fixing the host SVE state corruption issue: https://lore.kernel.org/linux-arm-kernel/20250121100026.3974971-1-mark.rutland@arm.com/ Patch 1 addresses the host SVE state corruption issue by always saving and unbinding the host state when loading a vCPU, as discussed on the earlier patch: https://lore.kernel.org/linux-arm-kernel/Z4--YuG5SWrP_pW7@J2N7QTR9R3/ https://lore.kernel.org/linux-arm-kernel/86plkful48.wl-maz@kernel.org/ Patches 2 to 4 remove code made redundant by patch 1. These probably warrant backporting along with patch 1 as there is some historical brokenness in the code they remove. Patches 5 to 7 are preparatory refactoring for patch 8, and are not intended to have any functional impact. Patch 8 addresses some mismanagement of ZCR_EL{1,2} which can result in the host VMM unexpectedly receiving a SIGKILL. To fix this, we eagerly switch ZCR_EL{1,2} at guest<->host transitions, as discussed on another series: https://lore.kernel.org/linux-arm-kernel/Z4pAMaEYvdLpmbg2@J2N7QTR9R3/ https://lore.kernel.org/linux-arm-kernel/86o6zzukwr.wl-maz@kernel.org/ https://lore.kernel.org/linux-arm-kernel/Z5Dc-WMu2azhTuMn@J2N7QTR9R3/ The end result is that KVM loses ~100 lines of code, and becomes a bit simpler to reason about. I've pushed these patches to the arm64-kvm-fpsimd-fixes-20250210 tag on my kernel.org repo: https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/ git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git The (unstable) arm64/kvm/fpsimd-fixes branch in that repo contains the fixes plus additional debug patches I've used for testing. I've given this some basic testing on a virtual platform, booting a host and a guest with and without constraining the guest's max SVE VL, with: * kvm_arm.mode=vhe * kvm_arm.mode=nvhe * kvm_arm.mode=protected (IIUC this will default to hVHE) Since v1 [1]: * Address some additional compiler warnings in patch 7 * Use ZCR_EL1 alias in VHE code * Fold in Tested-by and Reviewed-by tags * Fix typos Since v2 [2]: * Ensure context synchronization in patch 8 * Fold in Tested-by and Reviewed-by tags * Fix typos [1] https://lore.kernel.org/linux-arm-kernel/20250204152100.705610-1-mark.rutland@arm.com/ [2] https://lore.kernel.org/linux-arm-kernel/20250206141102.954688-1-mark.rutland@arm.com/ Mark. Mark Rutland (8): KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state KVM: arm64: Remove host FPSIMD saving for non-protected KVM KVM: arm64: Remove VHE host restore of CPACR_EL1.ZEN KVM: arm64: Remove VHE host restore of CPACR_EL1.SMEN KVM: arm64: Refactor CPTR trap deactivation KVM: arm64: Refactor exit handlers KVM: arm64: Mark some header functions as inline KVM: arm64: Eagerly switch ZCR_EL{1,2} arch/arm64/include/asm/kvm_emulate.h | 42 -------- arch/arm64/include/asm/kvm_host.h | 22 +--- arch/arm64/kernel/fpsimd.c | 25 ----- arch/arm64/kvm/arm.c | 8 -- arch/arm64/kvm/fpsimd.c | 100 ++---------------- arch/arm64/kvm/hyp/entry.S | 5 + arch/arm64/kvm/hyp/include/hyp/switch.h | 133 +++++++++++++++++------- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 15 ++- arch/arm64/kvm/hyp/nvhe/switch.c | 91 ++++++++-------- arch/arm64/kvm/hyp/vhe/switch.c | 33 +++--- 10 files changed, 187 insertions(+), 287 deletions(-) Reviewed-by: Oliver Upton