From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E4E2314A4F0; Mon, 8 Jun 2026 13:54:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780926844; cv=none; b=Uto/d1jDi63ZqMBDZUtR2XiIkrXoTYQGqsQ3P7kFNbQHYJg9amWSzSbD7s5qLAOLf+tjrtfIS1PJ8ydSxQwPspC1hIoPd0ryfGmGX00CFh5YfMi28zcYaV0DTraLdAgFeWD9NXvWmJjXPGjusnQxjCvcxYk+nAqSiYlUiDcARik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780926844; c=relaxed/simple; bh=zyFb9/SAECng/VTwTudQLxjUQyq0g0AZM0OK2JIT8NA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jNwy33/GQF9mqxdbkSOyouaWaFUiae6p3KHhQYPr2xjjh3WTrnZLtbw6ZSKpAShEuH+3215xNyZ5bY5aP/3zi+7nUDnL4k86KIyEX7PzWi/zVbdhZAnHWN6dfGp4RLHuk1jGpESPh45WVOkbgXOEtsQlmzby9THkU+uIfUx8upo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=Am229Gtp; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="Am229Gtp" 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 5FD22244B; Mon, 8 Jun 2026 06:53:57 -0700 (PDT) Received: from [10.57.28.93] (unknown [10.57.28.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4B1E43F86F; Mon, 8 Jun 2026 06:53:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1780926842; bh=zyFb9/SAECng/VTwTudQLxjUQyq0g0AZM0OK2JIT8NA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Am229GtpwnsAOTgPNgH0rKMU0izNXaGe3sEaiDNq7CSGq+5bEqKfsCQAYLrBmWu9g R3SFvmmvI0pML1LYEXP6f3iuiDl8j4v8RrDvp7FFT4rwKDMIrcT7jYncMiFsWKki02 FZWtyD5eqhQTmw5GvKPFroyhVAwfW/ZXzGJk0H/A= Message-ID: <9631be66-c757-488d-bb66-a62698aa26b8@arm.com> Date: Mon, 8 Jun 2026 14:53:56 +0100 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14 26/44] arm64: RMI: Allow populating initial contents To: Suzuki K Poulose , Gavin Shan , kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: 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 , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo.Pieralisi2@arm.com References: <20260513131757.116630-1-steven.price@arm.com> <20260513131757.116630-27-steven.price@arm.com> <0c71b4b8-ad0b-4a24-9f4a-180b2aaacdb6@arm.com> From: Steven Price Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 08/06/2026 10:41, Suzuki K Poulose wrote: > On 08/06/2026 10:36, Steven Price wrote: >> On 28/05/2026 06:30, Gavin Shan wrote: >>> Hi Steve, >>> >>> On 5/13/26 11:17 PM, Steven Price wrote: >>>> The VMM needs to populate the realm with some data before starting >>>> (e.g. >>>> a kernel and initrd). This is measured by the RMM and used as part of >>>> the attestation later on. >>>> >>>> Signed-off-by: Steven Price > > ... > >>>> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c >>>> index a89873a5eb77..209087bcf399 100644 >>>> --- a/arch/arm64/kvm/rmi.c >>>> +++ b/arch/arm64/kvm/rmi.c >>>> @@ -486,6 +486,75 @@ void kvm_realm_unmap_range(struct kvm *kvm, >>>> unsigned long start, >>>>            realm_unmap_private_range(kvm, start, end, may_block); >>>>    } >>>>    +static int realm_data_map_init(struct kvm *kvm, unsigned long ipa, >>>> +                   kvm_pfn_t dst_pfn, kvm_pfn_t src_pfn, >>>> +                   unsigned long flags) >>>> +{ >>>> +    struct realm *realm = &kvm->arch.realm; >>>> +    phys_addr_t rd = virt_to_phys(realm->rd); >>>> +    phys_addr_t dst_phys, src_phys; >>>> +    int ret; >>>> + >>>> +    dst_phys = __pfn_to_phys(dst_pfn); >>>> +    src_phys = __pfn_to_phys(src_pfn); >>>> + >>>> +    if (rmi_delegate_page(dst_phys)) >>>> +        return -ENXIO; >>>> + >>>> +    ret = rmi_rtt_data_map_init(rd, dst_phys, ipa, src_phys, flags); >>>> +    if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) { >>>> +        /* Create missing RTTs and retry */ >>>> +        int level = RMI_RETURN_INDEX(ret); >>>> + >>>> +        KVM_BUG_ON(level == KVM_PGTABLE_LAST_LEVEL, kvm); >>> >>>          KVM_BUG_ON(level >= KVM_PGTABLE_LAST_LEVEL, kvm); >> >> Ack. >> > > Thinking more about this, I guess a buggy VMM can trigger this > by populating twice ? (level == KVM_PGTABLE_LAST_LEVEL). So, we should > return the error back, than warning here and suppressing the error ? Populating twice causes rmi_delegate_page() to be run twice on the same page and the second one will then fail. So I don't think this is possible (please correct me if I've missed something!) Thanks, Steve