From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB79B1E49E for ; Thu, 20 Jun 2024 13:18:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718889505; cv=none; b=o0foeYsGirn5ItMl5XWd46JApeR+gbK46q6pbIOmrJNNGqpcnO0tRoV7RlnywHQ/bYeurn/3i0ZlzmlvoosNwJJfs6ml8iEYYvAfY9MRWX8k6BFVkTXBtNZpDh5djb1ZGfbNyVP2OoAWpGKgy0cTTOdiEJX7H2cfmfCcaqbAtq4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718889505; c=relaxed/simple; bh=MmfkCHH6aveXbJZTyXbt/djjYBat06YU0apaENdGPNk=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=STefG5hGKIo/VYqMlPhgAABpR9hn3wC0S4qwA3oNRbA+JqqoWEOruY5IylrlGELmVakDnu2KoHnxT/KW+aPbj/u+3S7No9DvRuyp75EpW9fa/UoSQdXt8MZ7ed8UhgsVBKT//gwqFGa41xObVuVAluDCEur5mGqJOTjBsKdDqIA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4W4gtM6wRRzwRqZ; Thu, 20 Jun 2024 21:14:03 +0800 (CST) Received: from kwepemm600007.china.huawei.com (unknown [7.193.23.208]) by mail.maildlp.com (Postfix) with ESMTPS id 6F8FE1800DD; Thu, 20 Jun 2024 21:18:20 +0800 (CST) Received: from [10.174.185.210] (10.174.185.210) by kwepemm600007.china.huawei.com (7.193.23.208) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 20 Jun 2024 21:18:19 +0800 Subject: Re: [PATCH] KVM: arm64: vgic-its: clear dte when mapd unmaps a device To: Marc Zyngier CC: Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Randy Dunlap , , , , , Eric Auger References: <20240613093811.710-1-jiangkunkun@huawei.com> <86v82ckimh.wl-maz@kernel.org> From: Kunkun Jiang Message-ID: <98e8cd74-621f-a445-4c43-e6948e6c79d9@huawei.com> Date: Thu, 20 Jun 2024 21:18:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <86v82ckimh.wl-maz@kernel.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600007.china.huawei.com (7.193.23.208) Hi Marc， Thank you very much for reviewing. On 2024/6/13 22:44, Marc Zyngier wrote: > On Thu, 13 Jun 2024 10:38:11 +0100, > Kunkun Jiang wrote: >> vgic_its_save_device_tables will traverse its->device_list to >> save dte for each device. vgic_its_restore_device_tables will >> traverse each entry of device table and check if it is valid. >> Restore if valid. >> >> But when mapd unmaps a devices, we do not invalidate the >> corresponding dte. In the scenario of continuous save >> and restore, there may be a situation where a device's dte >> is not saved but is restored. This is unreasonable and may >> cause restore to fail. This patch clears the corresponding >> dte when mapd unmaps a device. >> >> Singed-off-by: Shusen Li > ^^^^^^^^^^^^^ This isn't a valid tag! > >> Signed-off-by: Kunkun Jiang > Something is wrong. Either Shusen Li is the author and you are merely > posting it, in which case there should be a 'From' line in the commit > message, or you are co-authors and there should be a 'Co-developed-by' > right after Shusen Li's SoB. > > Please read Documentation/process/submitting-patches.rst for the > details. The latest patch has been modified. See link below. >> --- >> arch/arm64/kvm/vgic/vgic-its.c | 13 +++++++++++-- >> 1 file changed, 11 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c >> index 40bb43f20bf3..dd5fba1e8ba3 100644 >> --- a/arch/arm64/kvm/vgic/vgic-its.c >> +++ b/arch/arm64/kvm/vgic/vgic-its.c >> @@ -1140,8 +1140,12 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its, >> u8 num_eventid_bits = its_cmd_get_size(its_cmd); >> gpa_t itt_addr = its_cmd_get_ittaddr(its_cmd); >> struct its_device *device; >> + gpa_t gpa; >> + const struct vgic_its_abi *abi; >> + int dte_esz; >> + u64 val; > Aside from 'gpa', all the extra variables should be moved into the > !valid block. And it would be nicer if this variable was called > something more descriptive. > >> >> - if (!vgic_its_check_id(its, its->baser_device_table, device_id, NULL)) >> + if (!vgic_its_check_id(its, its->baser_device_table, device_id, &gpa)) >> return E_ITS_MAPD_DEVICE_OOR; >> >> if (valid && num_eventid_bits > VITS_TYPER_IDBITS) >> @@ -1161,8 +1165,13 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its, >> * The spec does not say whether unmapping a not-mapped device >> * is an error, so we are done in any case. >> */ >> - if (!valid) >> + if (!valid) { >> + abi = vgic_its_get_abi(its); >> + dte_esz = abi->dte_esz; >> + val = cpu_to_le64(0); >> + vgic_write_guest_lock(kvm, gpa, &val, dte_esz); > This is just a bit wrong: > > - you store 0 in a u64 after having (pointlessly) converted it to le64 > > - you write 'dte_esz' bytes into guest memory, but you don't have any > check whether this is *larger* than the u64 you have passed The latest patch has been modified. See link below. > Similar issue exists in all the vgic_its_save_*() functions, calling > for a generic fix, as we're just lucky to never have needed a new ABI > so far. At the very least a check that we deal with data that is > exactly 8 bytes. A patch has been added to check it. Link: https://lore.kernel.org/kvmarm/20240620130650.1279-1-jiangkunkun@huawei.com/ Thanks, Kunkun Jiang