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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 83630C3DA7F for ; Mon, 5 Aug 2024 23:57:41 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ltAj9C7x; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4WdCzm1Tw0z3cYW for ; Tue, 6 Aug 2024 09:57:40 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ltAj9C7x; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.dev (client-ip=2001:41d0:203:375::ac; helo=out-172.mta1.migadu.com; envelope-from=oliver.upton@linux.dev; receiver=lists.ozlabs.org) Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [IPv6:2001:41d0:203:375::ac]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4WdCyq2r7jz30V1 for ; Tue, 6 Aug 2024 09:56:48 +1000 (AEST) Date: Mon, 5 Aug 2024 23:56:18 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1722902186; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pN1+APSAtAExH8nmjZxjfeQ8B4XYksdtaPF9+NGomwI=; b=ltAj9C7xL0C220uapJ5lUkG5kNHP2zZtS1WYxPlhAzd6j+Tb/QV3RDuco0pM+j1z556Q9A hoU/lQELQ0mjJMI+uXIgqaezOeALKRjbAQbjCFVaZB2D2C3tgIkiE36obKMbKTDvluByU8 L3cwZkpNHubjmM0zvEZGMwTs9FMKJX4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Sean Christopherson Subject: Re: [PATCH v12 54/84] KVM: arm64: Mark "struct page" pfns accessed/dirty before dropping mmu_lock Message-ID: References: <20240726235234.228822-1-seanjc@google.com> <20240726235234.228822-55-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, David Matlack , linux-riscv@lists.infradead.org, Claudio Imbrenda , Marc Zyngier , Janosch Frank , Huacai Chen , Fuad Tabba , Christian Borntraeger , Albert Ou , Bibo Mao , loongarch@lists.linux.dev, Paul Walmsley , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Palmer Dabbelt , David Stevens , kvm-riscv@lists.infradead.org, Anup Patel , Paolo Bonzini , Tianrui Zhao , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Aug 05, 2024 at 04:53:01PM -0700, Sean Christopherson wrote: > On Mon, Aug 05, 2024, Oliver Upton wrote: > > > > --- > > > > arch/arm64/kvm/mmu.c | 10 ++++++---- > > > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > > > > index 22ee37360c4e..ce13c3d884d5 100644 > > > > --- a/arch/arm64/kvm/mmu.c > > > > +++ b/arch/arm64/kvm/mmu.c > > > > @@ -1685,15 +1685,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > > > > } > > > > > > > > out_unlock: > > > > + if (writable && !ret) > > > > + kvm_set_pfn_dirty(pfn); > > > > > > I'm guessing you meant kvm_release_pfn_dirty() here, because this leaks > > > a reference. > > Doh, I did indeed. Alternatively, this could be: > > if (writable && !ret) > kvm_set_pfn_dirty(pfn); > > kvm_release_pfn_clean(pfn); > > It won't matter in the end, because this just becomes: > > kvm_release_faultin_page(kvm, page, !!ret, writable); > > So I guess the question is if you prefer to make the switch to an if-else in this > path, or more implicitly in the conversion to kvm_release_faultin_page(). > > I made the same goof for RISC-V, perhaps to prove that I too can copy+paste arm64's > MMU code ;-) LOL, whatever way you want to address it is fine by me, just wanted to make sure this intermediate bug wouldn't bite an unlucky bisection. -- Thanks, Oliver