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Fri, 7 Feb 2025 20:53:43 +0000 (GMT) From: Matthew Rosato To: joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, gerald.schaefer@linux.ibm.com, schnelle@linux.ibm.com Cc: hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, borntraeger@linux.ibm.com, farman@linux.ibm.com, clegoate@redhat.com, jgg@nvidia.com, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH v4 4/4] iommu/s390: implement iommu passthrough via identity domain Date: Fri, 7 Feb 2025 15:53:35 -0500 Message-ID: <20250207205335.473946-5-mjrosato@linux.ibm.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250207205335.473946-1-mjrosato@linux.ibm.com> References: <20250207205335.473946-1-mjrosato@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 7RmOy9Z-AUBYM8Vl9LmKW1AwUR2KXSDy X-Proofpoint-ORIG-GUID: 7RmOy9Z-AUBYM8Vl9LmKW1AwUR2KXSDy X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-07_09,2025-02-07_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 clxscore=1015 lowpriorityscore=0 phishscore=0 impostorscore=0 bulkscore=0 adultscore=0 malwarescore=0 mlxlogscore=999 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2501170000 definitions=main-2502070153 Content-Type: text/plain; charset="utf-8" Enabled via the kernel command-line 'iommu.passthrough=3D1' option. Introduce the concept of identity domains to s390-iommu, which relies on the bus_dma_region to offset identity mappings to the start of the DMA aperture advertized by CLP. Signed-off-by: Matthew Rosato Reviewed-by: Niklas Schnelle Tested-by: Niklas Schnelle --- drivers/iommu/s390-iommu.c | 95 +++++++++++++++++++++++++++++--------- 1 file changed, 72 insertions(+), 23 deletions(-) diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c index 007ccfdad495..e1c76e0f9c2b 100644 --- a/drivers/iommu/s390-iommu.c +++ b/drivers/iommu/s390-iommu.c @@ -16,7 +16,7 @@ =20 #include "dma-iommu.h" =20 -static const struct iommu_ops s390_iommu_ops; +static const struct iommu_ops s390_iommu_ops, s390_iommu_rtr_ops; =20 static struct kmem_cache *dma_region_table_cache; static struct kmem_cache *dma_page_table_cache; @@ -432,9 +432,11 @@ static int blocking_domain_attach_device(struct iommu_= domain *domain, return 0; =20 s390_domain =3D to_s390_domain(zdev->s390_domain); - spin_lock_irqsave(&s390_domain->list_lock, flags); - list_del_rcu(&zdev->iommu_list); - spin_unlock_irqrestore(&s390_domain->list_lock, flags); + if (zdev->dma_table) { + spin_lock_irqsave(&s390_domain->list_lock, flags); + list_del_rcu(&zdev->iommu_list); + spin_unlock_irqrestore(&s390_domain->list_lock, flags); + } =20 zpci_unregister_ioat(zdev, 0); zdev->dma_table =3D NULL; @@ -762,7 +764,13 @@ int zpci_init_iommu(struct zpci_dev *zdev) if (rc) goto out_err; =20 - rc =3D iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL); + if (zdev->rtr_avail) { + rc =3D iommu_device_register(&zdev->iommu_dev, + &s390_iommu_rtr_ops, NULL); + } else { + rc =3D iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, + NULL); + } if (rc) goto out_sysfs; =20 @@ -826,6 +834,39 @@ static int __init s390_iommu_init(void) } subsys_initcall(s390_iommu_init); =20 +static int s390_attach_dev_identity(struct iommu_domain *domain, + struct device *dev) +{ + struct zpci_dev *zdev =3D to_zpci_dev(dev); + u8 status; + int cc; + + blocking_domain_attach_device(&blocking_domain, dev); + + /* If we fail now DMA remains blocked via blocking domain */ + cc =3D s390_iommu_domain_reg_ioat(zdev, domain, &status); + + /* + * If the device is undergoing error recovery the reset code + * will re-establish the new domain. + */ + if (cc && status !=3D ZPCI_PCI_ST_FUNC_NOT_AVAIL) + return -EIO; + + zdev_s390_domain_update(zdev, domain); + + return 0; +} + +static const struct iommu_domain_ops s390_identity_ops =3D { + .attach_dev =3D s390_attach_dev_identity, +}; + +static struct iommu_domain s390_identity_domain =3D { + .type =3D IOMMU_DOMAIN_IDENTITY, + .ops =3D &s390_identity_ops, +}; + static struct iommu_domain blocking_domain =3D { .type =3D IOMMU_DOMAIN_BLOCKED, .ops =3D &(const struct iommu_domain_ops) { @@ -833,23 +874,31 @@ static struct iommu_domain blocking_domain =3D { } }; =20 -static const struct iommu_ops s390_iommu_ops =3D { - .blocked_domain =3D &blocking_domain, - .release_domain =3D &blocking_domain, - .capable =3D s390_iommu_capable, - .domain_alloc_paging =3D s390_domain_alloc_paging, - .probe_device =3D s390_iommu_probe_device, - .device_group =3D generic_device_group, - .pgsize_bitmap =3D SZ_4K, - .get_resv_regions =3D s390_iommu_get_resv_regions, - .default_domain_ops =3D &(const struct iommu_domain_ops) { - .attach_dev =3D s390_iommu_attach_device, - .map_pages =3D s390_iommu_map_pages, - .unmap_pages =3D s390_iommu_unmap_pages, - .flush_iotlb_all =3D s390_iommu_flush_iotlb_all, - .iotlb_sync =3D s390_iommu_iotlb_sync, - .iotlb_sync_map =3D s390_iommu_iotlb_sync_map, - .iova_to_phys =3D s390_iommu_iova_to_phys, - .free =3D s390_domain_free, +#define S390_IOMMU_COMMON_OPS() \ + .blocked_domain =3D &blocking_domain, \ + .release_domain =3D &blocking_domain, \ + .capable =3D s390_iommu_capable, \ + .domain_alloc_paging =3D s390_domain_alloc_paging, \ + .probe_device =3D s390_iommu_probe_device, \ + .device_group =3D generic_device_group, \ + .pgsize_bitmap =3D SZ_4K, \ + .get_resv_regions =3D s390_iommu_get_resv_regions, \ + .default_domain_ops =3D &(const struct iommu_domain_ops) { \ + .attach_dev =3D s390_iommu_attach_device, \ + .map_pages =3D s390_iommu_map_pages, \ + .unmap_pages =3D s390_iommu_unmap_pages, \ + .flush_iotlb_all =3D s390_iommu_flush_iotlb_all, \ + .iotlb_sync =3D s390_iommu_iotlb_sync, \ + .iotlb_sync_map =3D s390_iommu_iotlb_sync_map, \ + .iova_to_phys =3D s390_iommu_iova_to_phys, \ + .free =3D s390_domain_free, \ } + +static const struct iommu_ops s390_iommu_ops =3D { + S390_IOMMU_COMMON_OPS() +}; + +static const struct iommu_ops s390_iommu_rtr_ops =3D { + .identity_domain =3D &s390_identity_domain, + S390_IOMMU_COMMON_OPS() }; --=20 2.48.1