From patchwork Thu Feb 6 14:10:54 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13963155 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 7086EC02194 for ; Thu, 6 Feb 2025 14:15:54 +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=jY/M1Di5W5T0Mlu92AFW/gNksF8Ks5jFZoyam7gJ1VE=; b=yhLVH0mxvock+ikVmwZVJGK2dP dA86aIRIDvg/Ad6pLOA3Xon4mtypjZOnhXnJHa1Vwvd6Jgf/oXJ5/Vcp+zTeMJXShmoe2WSO6ErXW xdEJu31fw8jdEoMUZgYJYKwqnLbnK72OLrNiOWWxJajgOGbbEH6wz/k/sSMckw+FtA31rNENcqKfd jAbJ6WhwcaxAiGuu7Md9Bq9MXTsqqN1lqScDOC1i7Lvl7dJRvGO1lzAFM7FZLsmz14mfZoaKbk+vy s3/o5Lxf8PaZ775yIcb3bqRx9/5ylBQeJ95pvcFDdr92FPPlTv3CoTxdcR+mDcBVu74tN4iT+vOkP nXSZJjzw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tg2fP-00000006XWu-2Al3; Thu, 06 Feb 2025 14:15:43 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tg2b8-00000006Wv2-2aaP for linux-arm-kernel@lists.infradead.org; Thu, 06 Feb 2025 14:11:20 +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 D52AF1063; Thu, 6 Feb 2025 06:11:39 -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 238243F63F; Thu, 6 Feb 2025 06:11:13 -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 v2 0/8] KVM: arm64: FPSIMD/SVE/SME fixes Date: Thu, 6 Feb 2025 14:10:54 +0000 Message-Id: <20250206141102.954688-1-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-20250206_061118_748626_5E2B6F23 X-CRM114-Status: GOOD ( 11.86 ) 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-20250206 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 [1] https://lore.kernel.org/linux-arm-kernel/20250204152100.705610-1-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/include/hyp/switch.h | 125 +++++++++++++++++------- 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 ++++--- 9 files changed, 174 insertions(+), 287 deletions(-) Reviewed-by: Mark Brown Tested-by: Mark Brown