From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97C89606D819 for ; Mon, 9 Nov 2026 13:37:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=uJPF6yce; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=hqlHWuAO 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-Unsubscribe-Post: List-Owner; bh=XLjVVqRd3p8pCryT/VdTNuVykrHMu0nh/BoWx9VVYBY=; b=uJPF6yceWaebGZ OVVtQI3DlG2uZ7azFJCedLrUUuBufIb7lVqzZOzoZNdOrLmSZm1CnTJo3CZyTiM64G//GLoB5V4mM onH3kPRpTpKNSmg4bBVUWzvrKXz0oRRScEZff5cg693aJaLa9F1X3lOMMHaKvQt03admPzR6u0kur exyUUMl5SnnC//dxx7qJ/+E68eTBFZSil6MIwlE1mf+bwmiXbyjKYvWlQ3/xOKIJHXOlPKw0OAUYI X2ANTJL0Jh3eB6znka/k1OLMOHFcAcpjUG6pYRhAg/dswdpLZGwrZXTwkhsYKuHT8nM1aEmhsI97h mWXWqvJMtAKMj7jEyF7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQPYp-00000000qCn-0ySl; Mon, 09 Nov 2026 13:37:23 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQPYk-00000000qAB-3S5j for linux-arm-kernel@lists.infradead.org; Mon, 09 Nov 2026 13:37:22 +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 ACB4014BF; Mon, 9 Nov 2026 05:37:12 -0800 (PST) Received: from [10.57.60.25] (unknown [10.57.60.25]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AD2543F632; Mon, 9 Nov 2026 05:37:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794231435; bh=NnQ/lEoIzA5Usu4Fnnce/QHJMYYmA9ABd8vXbiATAAQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=hqlHWuAOhP2c6MKtExUEUsXcpTvjTSy/wmSieETuzLi3Tp9gaYEk34F5HIiSJJGGO hjEnQpAD91vJGTYBOKKPDeTPncDQybIkK8mynI3UZeNxt32odugTQYOrDZ/eg9ywOu gIBIPBiML6bNn8UnkUiygB6P8gIDKVKxRVz4+FTc= Message-ID: <473e0c95-e027-44dc-a355-eed26d8a3926@arm.com> Date: Mon, 9 Nov 2026 13:37:03 +0000 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 10/11] KVM: arm64: CCA: Support runtime faulting of memory To: Fuad Tabba , Suzuki K Poulose 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 , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo Pieralisi References: <20261102141304.126883-1-steven.price@arm.com> <20261102141304.126883-11-steven.price@arm.com> From: Steven Price Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261109_053719_046768_1E8F29FA X-CRM114-Status: GOOD ( 17.61 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-12.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 09/11/2026 07:40, Fuad Tabba wrote: > Hi Suzuki, Steve, Hi Fuad, > On Thu, 05 Nov 2026 17:30:16 +0000, Suzuki K Poulose > wrote: > [...] >>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > [...] >>> @@ -1816,13 +1828,28 @@ static int gmem_abort(const struct kvm_s2_fault_desc *s2fd, >>> /* Pairs with the smp_wmb() in kvm_mmu_invalidate_end(). */ >>> smp_rmb(); >>> >>> + if (kvm_vm_is_realm(kvm)) { >>> + is_realm_private = kvm_realm_is_private_address(&kvm->arch.realm, >>> + s2fd->fault_ipa); >>> + >>> + if (is_realm_private != kvm_gmem_is_private_gfn(kvm, canonical_gfn)) { > [...] >> I am wondering there is a way to make it a bit more generic. The issue >> is, only Realm has private memory with guest_memfd for now. Don't know >> the pKVM plans for it. > > The plan is for protected pKVM VMs to be backed by guest_memfd too, > which would also hold each page's private/shared state [1]. So > kvm_arch_has_private_mem() will be true for them, and this comparison > applies as is. Only how the expected state is computed differs: for a > pVM it comes from the per-page share state rather than an IPA bit. > > Steve, could you gate the guest_memfd checks on > kvm_arch_has_private_mem(kvm) rather than kvm_vm_is_realm(), this one > and the memslot check you proposed for 02/11? Only the > kvm_realm_is_private_address() and realm_map_ipa() calls are > realm-specific, and they could be VM_REALM cases of a switch on > vm_flavor, as Marc asked for on the v21 memslot check [2]. The macro > would then only widen to protected VMs when pKVM's guest_memfd support > lands. Sure I can include that in v2. Thanks, Steve > Cheers, > /fuad > > [1] https://lore.kernel.org/all/CA+EHjTz+WgXEW5RTxXf4oGeEb1Tsm5Ha4nOc4S1jBcp7jxP4+A@mail.gmail.com/ > [2] https://lore.kernel.org/all/86mrsw2jrn.wl-maz@kernel.org/