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 X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CD76C433DF for ; Mon, 24 Aug 2020 11:30:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 618DD20FC3 for ; Mon, 24 Aug 2020 11:30:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598268642; bh=RYREpAI28puv40pLrLSlY6MDo5We/pnypNIl1J6niFo=; h=From:To:Cc:Subject:Date:List-ID:From; b=gvSFAICQCqjFg1tw78IPutlakJ8dXJnSelcx5/bAIRHEOk0IUgXkawM20FunBXPL+ gpA4DcO4WNg2LFyoM86xxfpixgnKTFrR0/sEjy+uWIKdEo/luBIxutV7t/v00FjbxE it/LEaK5q64jMeQcDTbONvJrICvN6VVKJ/0YRk80= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726924AbgHXLah (ORCPT ); Mon, 24 Aug 2020 07:30:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:39976 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726851AbgHXL37 (ORCPT ); Mon, 24 Aug 2020 07:29:59 -0400 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7DD752074D; Mon, 24 Aug 2020 11:29:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598268599; bh=RYREpAI28puv40pLrLSlY6MDo5We/pnypNIl1J6niFo=; h=From:To:Cc:Subject:Date:From; b=BJ9aHSXFWzl9fJVfAab7dQ6+PbFPxcGVDzJrzO/knml4i+uBeuVDWZnDRAN1sEw5g 238gz4Iu4FQBfxZHkSVVVM2RuIRYf1QudUhqmMdHqeqmCC5KZyrxks3UF9/S1Z9KHM FSAkpW9xEcVwb8b/wY+gx53ZKoWxRQCy1Qx6/Dsg= From: Will Deacon To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, maz@kernel.org, suzuki.poulose@arm.com, james.morse@arm.com, pbonzini@redhat.com, kernel-team@android.com, Will Deacon , stable@vger.kernel.org Subject: [PATCH stable-4.14.y backport] KVM: arm/arm64: Don't reschedule in unmap_stage2_range() Date: Mon, 24 Aug 2020 12:29:54 +0100 Message-Id: <20200824112954.24756-1-will@kernel.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Upstream commits fdfe7cbd5880 ("KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()") and b5331379bc62 ("KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set") fix a "sleeping from invalid context" BUG caused by unmap_stage2_range() attempting to reschedule when called on the OOM path. Unfortunately, these patches rely on the MMU notifier callback being passed knowledge about whether or not blocking is permitted, which was introduced in 4.19. Rather than backport this considerable amount of infrastructure just for KVM on arm, instead just remove the conditional reschedule. Cc: # v4.14 only Cc: Marc Zyngier Cc: Suzuki K Poulose Cc: James Morse Signed-off-by: Will Deacon --- virt/kvm/arm/mmu.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 3814cdad643a..7fe673248e98 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -307,12 +307,6 @@ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) next = stage2_pgd_addr_end(addr, end); if (!stage2_pgd_none(*pgd)) unmap_stage2_puds(kvm, pgd, addr, next); - /* - * If the range is too large, release the kvm->mmu_lock - * to prevent starvation and lockup detector warnings. - */ - if (next != end) - cond_resched_lock(&kvm->mmu_lock); } while (pgd++, addr = next, addr != end); } -- 2.28.0.297.g1956fa8f8d-goog