From patchwork Tue Mar 11 14:10:43 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shameerali Kolothum Thodi X-Patchwork-Id: 14011947 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.gnu.org (lists.gnu.org [209.51.188.17]) (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 9FD73C282EC for ; Tue, 11 Mar 2025 14:15:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ts0OB-0002oV-S6; Tue, 11 Mar 2025 10:15:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ts0Nc-0002RN-Ho; Tue, 11 Mar 2025 10:14:49 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ts0NZ-0007Gi-5T; Tue, 11 Mar 2025 10:14:48 -0400 Received: from mail.maildlp.com (unknown [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4ZBwfw4b6sz6D9b5; Tue, 11 Mar 2025 22:11:36 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id 7D2B71404F5; Tue, 11 Mar 2025 22:14:43 +0800 (CST) Received: from A2303104131.china.huawei.com (10.203.177.241) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 11 Mar 2025 15:14:36 +0100 To: , CC: , , , , , , , , , , , , , Subject: [RFC PATCH v2 18/20] hw/arm/smmu-common: Bypass emulated IOTLB for a accel SMMUv3 Date: Tue, 11 Mar 2025 14:10:43 +0000 Message-ID: <20250311141045.66620-19-shameerali.kolothum.thodi@huawei.com> X-Mailer: git-send-email 2.12.0.windows.1 In-Reply-To: <20250311141045.66620-1-shameerali.kolothum.thodi@huawei.com> References: <20250311141045.66620-1-shameerali.kolothum.thodi@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.203.177.241] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To frapeml500008.china.huawei.com (7.182.85.71) Received-SPF: pass client-ip=185.176.79.56; envelope-from=shameerali.kolothum.thodi@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Shameer Kolothum X-Patchwork-Original-From: Shameer Kolothum via From: Shameerali Kolothum Thodi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Nicolin Chen If a vSMMU is configured as a accelerated one, HW IOTLB will be used and all cache invalidation should be done to the HW IOTLB too, v.s. the emulated iotlb. In this case, an iommu notifier isn't registered, as the devices behind a SMMUv3-accel would stay in the system address space for stage-2 mappings. However, the KVM code still requests an iommu address space to translate an MSI doorbell gIOVA via get_msi_address_space() and translate(). Since a SMMUv3-accel doesn't register an iommu notifier to flush emulated iotlb, bypass the emulated IOTLB and always walk through the guest-level IO page table. Signed-off-by: Nicolin Chen Signed-off-by: Shameer Kolothum --- hw/arm/smmu-common.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c index 9fd455baa0..fd10df8866 100644 --- a/hw/arm/smmu-common.c +++ b/hw/arm/smmu-common.c @@ -77,6 +77,17 @@ static SMMUTLBEntry *smmu_iotlb_lookup_all_levels(SMMUState *bs, uint8_t level = 4 - (inputsize - 4) / stride; SMMUTLBEntry *entry = NULL; + /* + * Stage-1 translation with a accel SMMU in general uses HW IOTLB. However, + * KVM still requests for an iommu address space for an MSI fixup by looking + * up stage-1 page table. Make sure we don't go through the emulated pathway + * so that the emulated iotlb will not need any invalidation. + */ + + if (bs->accel) { + return NULL; + } + while (level <= 3) { uint64_t subpage_size = 1ULL << level_shift(level, tt->granule_sz); uint64_t mask = subpage_size - 1; @@ -142,6 +153,16 @@ void smmu_iotlb_insert(SMMUState *bs, SMMUTransCfg *cfg, SMMUTLBEntry *new) SMMUIOTLBKey *key = g_new0(SMMUIOTLBKey, 1); uint8_t tg = (new->granule - 10) / 2; + /* + * Stage-1 translation with a accel SMMU in general uses HW IOTLB. However, + * KVM still requests for an iommu address space for an MSI fixup by looking + * up stage-1 page table. Make sure we don't go through the emulated pathway + * so that the emulated iotlb will not need any invalidation. + */ + if (bs->accel) { + return; + } + if (g_hash_table_size(bs->iotlb) >= SMMU_IOTLB_MAX_SIZE) { smmu_iotlb_inv_all(bs); }