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 5AE65C55184 for ; Tue, 4 Aug 2026 12:16:23 +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:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qfiH5twDnELxoWkEWNQ53HPaRUzKBcx6UJ6WQR0aCQQ=; b=Y6ZRDycHni04zVUgdGw+QsLUCC ly+eh+OAL1ZNJ7xjVvnyHBMu0IGuALuR29fkl8Zqm4NnQB2hKRioO+zGKqeeBTVvQwr+iVozKD3hj lQzdCbyKRtVxGzYQKWMEiMgKGojzNiHzNJN1RXeybNxesb8n8yVl7GVBnR9/w0OmlxDS+nvuIMv89 Gzp9RTPFX6O7UVMN+PWJPB+NFSmPdN4aX+ac70/05U6oBjQnqL6Uf5yE/gabDMCRL/r2FIq/+Hr62 qPqmAfPwdKyjJZZiYwfAooTghWO5l+9oumhI8qthinqcwa3qBoq19jYikaAcOqPbjaV1TPQzjlxui sUiP4Rfg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrE43-00000001n4w-30mo; Tue, 04 Aug 2026 12:16:11 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrE41-00000001n4b-49TJ for linux-arm-kernel@lists.infradead.org; Tue, 04 Aug 2026 12:16:11 +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 EF8851476; Tue, 4 Aug 2026 05:16:03 -0700 (PDT) Received: from [10.57.44.180] (unknown [10.57.44.180]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E55483F66F; Tue, 4 Aug 2026 05:16:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785845768; bh=bcAMhZTiy49tEojqvYK5r5G3B51T0weL1dSTwGIlZwY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=c6UEwA1tfFd2CmIo6fSWGXXuYEzA2q181oOLDQYEGFGK+6ReJcnh1HF8CmR55UEwS 4KYLjtJBdGc+eGUnk52Cn0Ek0phGnFAEbNgF42/95p8y/PHexLLabxa6ezN6urQQx8 oo4Cl+2TiqW9TB+qhDx/Li/qJmx1beTxD+VNJIHc= Message-ID: Date: Tue, 4 Aug 2026 13:16:00 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v16 17/45] KVM: arm64: CCA: Tear down RTTs Content-Language: en-GB To: Alper Gun , Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo Pieralisi References: <20260803134403.80630-1-steven.price@arm.com> <20260803134403.80630-18-steven.price@arm.com> From: Suzuki K Poulose In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260804_051610_102204_021DB8E0 X-CRM114-Status: GOOD ( 20.31 ) 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 Hi there On 03/08/2026 23:29, Alper Gun wrote: > On Mon, Aug 3, 2026 at 6:45 AM Steven Price wrote: >> [...] >> +static void realm_unmap_stage2(struct kvm *kvm) >> +{ >> + struct realm *realm = &kvm->arch.realm; >> + >> + lockdep_assert_held(&kvm->arch.config_lock); >> + >> + if (realm->stage2_unmapped) >> + return; >> + >> + write_lock(&kvm->mmu_lock); >> + kvm_stage2_unmap_range(&kvm->arch.mmu, 0, >> + BIT(realm->ia_bits - 1), true); >> + write_unlock(&kvm->mmu_lock); >> + >> + realm->stage2_unmapped = true; >> +} >> + >> +int kvm_realm_teardown_stage2(struct kvm *kvm) >> +{ >> + lockdep_assert_held(&kvm->arch.config_lock); >> + >> + realm_unmap_stage2(kvm); >> + return realm_destroy_rtts(kvm); >> +} > > Hi Steven, > > I noticed a warning in dmesg when destroying a realm: > > [ 158.533495] Call trace: > [ 158.535927] kvm_destroy_realm+0x208/0x218 > [ 158.540356] kvm_arch_destroy_vm+0xc8/0xd8 > [ 158.544439] kvm_put_kvm+0x324/0x4b0 > [ 158.548002] kvm_vm_stats_release+0x1c/0x38 Thanks for the report and the detailed analysis. > > I traced this and found the following: > > At this point, calling realm_destroy_rtts() may fail destroying the RTTs > because RECs are still active and the Realm is not terminated, but the > walk finishes and still sets realm->rtts_destroyed = true. > > Later, kvm_destroy_realm() calls rmi_realm_terminate() and then calls > realm_destroy_rtts(kvm) again. But because realm->rtts_destroyed is already > set to true, it exits early without tearing down the RTTs. > > Consequently, rmi_realm_destroy() is invoked while the RTT tables still > exist in RMM, which fails and triggers WARN_ON(rmi_realm_destroy). > > The fix I used was to remove realm_destroy_rtts() from > kvm_realm_teardown_stage2(): > --- a/arch/arm64/kvm/rmi.c > +++ b/arch/arm64/kvm/rmi.c > @@ -434,7 +434,7 @@ int kvm_realm_teardown_stage2(struct kvm *kvm) > lockdep_assert_held(&kvm->arch.config_lock); > > realm_unmap_stage2(kvm); > - return realm_destroy_rtts(kvm); > + return 0; > } > > I think we don't need RTT destruction here as it will be handled cleanly in > kvm_destroy_realm() later. That sounds sensible to me, I will take a look and fix it locally for the next version. Thanks Suzuki > > Thanks, > Alper