| Message ID | 5d89190b35720bf5b66621f46b6d3c85323d8eab.1702486837.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | dma-mapping: Simplify arch_setup_dma_ops() | expand |
On Wed, Dec 13, 2023 at 05:17:59PM +0000, Robin Murphy wrote: > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 27a167f4cd3e..d808c8dcf5cb 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -1724,25 +1724,20 @@ static const struct dma_map_ops iommu_dma_ops = { > .opt_mapping_size = iommu_dma_opt_mapping_size, > }; > > -/* > - * The IOMMU core code allocates the default DMA domain, which the underlying > - * IOMMU driver needs to support via the dma-iommu layer. > - */ > -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit) > +void iommu_setup_dma_ops(struct device *dev) > { > struct iommu_domain *domain = iommu_get_domain_for_dev(dev); > > - if (!domain) > - goto out_err; > + if (dev_is_pci(dev)) > + dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac; > > - /* > - * The IOMMU core code allocates the default DMA domain, which the > - * underlying IOMMU driver needs to support via the dma-iommu layer. > - */ > if (iommu_is_dma_domain(domain)) { ... > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 824989874dee..43f630d0530e 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -560,10 +560,10 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list > if (list_empty(&group->entry)) > list_add_tail(&group->entry, group_list); > } > - mutex_unlock(&group->mutex); > > - if (dev_is_pci(dev)) > - iommu_dma_set_pci_32bit_workaround(dev); > + iommu_setup_dma_ops(dev); With Intel VT-d (QEMU emulation) I get a crash in iommu_setup_dma_ops() because at this point group->domain and group->default_domain are still NULL, group_list is non-NULL. No problem with x86 virtio-iommu, it goes through iommu_setup_default_domain() earlier in the function. Arm virtio-iommu is fine too. Thanks, Jean
On 2023-12-14 4:51 pm, Jean-Philippe Brucker wrote: > On Wed, Dec 13, 2023 at 05:17:59PM +0000, Robin Murphy wrote: >> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c >> index 27a167f4cd3e..d808c8dcf5cb 100644 >> --- a/drivers/iommu/dma-iommu.c >> +++ b/drivers/iommu/dma-iommu.c >> @@ -1724,25 +1724,20 @@ static const struct dma_map_ops iommu_dma_ops = { >> .opt_mapping_size = iommu_dma_opt_mapping_size, >> }; >> >> -/* >> - * The IOMMU core code allocates the default DMA domain, which the underlying >> - * IOMMU driver needs to support via the dma-iommu layer. >> - */ >> -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit) >> +void iommu_setup_dma_ops(struct device *dev) >> { >> struct iommu_domain *domain = iommu_get_domain_for_dev(dev); >> >> - if (!domain) >> - goto out_err; >> + if (dev_is_pci(dev)) >> + dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac; >> >> - /* >> - * The IOMMU core code allocates the default DMA domain, which the >> - * underlying IOMMU driver needs to support via the dma-iommu layer. >> - */ >> if (iommu_is_dma_domain(domain)) { > > ... > >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index 824989874dee..43f630d0530e 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -560,10 +560,10 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list >> if (list_empty(&group->entry)) >> list_add_tail(&group->entry, group_list); >> } >> - mutex_unlock(&group->mutex); >> >> - if (dev_is_pci(dev)) >> - iommu_dma_set_pci_32bit_workaround(dev); >> + iommu_setup_dma_ops(dev); > > With Intel VT-d (QEMU emulation) I get a crash in iommu_setup_dma_ops() > because at this point group->domain and group->default_domain are still > NULL, group_list is non-NULL. Ugh, clearly I'd manage to confuse myself, since what I wrote in the changelog isn't even right... Taking yet another look, there's not actually one single place we can do this right now which will work in a manageable way for all cases. With 2 or 3 more levels of mess unpicked it's going to clean up much further (it's also becoming clear that iommu-dma wants better separation of its own per-device and per-domain bits), but for the immediate task in this series of finally getting out of arch code, I guess that continuing to echo the current probe_finalize flows is going to be safest. Something like the diff below (but I'll have a further think about it with a fresh head tomorrow). Thanks, Robin. ----->8----- diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 8972b7f22a9a..ba4cd5251205 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -562,7 +562,8 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list list_add_tail(&group->entry, group_list); } - iommu_setup_dma_ops(dev); + if (group->default_domain) + iommu_setup_dma_ops(dev); mutex_unlock(&group->mutex); @@ -1992,6 +1993,8 @@ int bus_iommu_probe(const struct bus_type *bus) mutex_unlock(&group->mutex); return ret; } + for_each_group_device(group, gdev) + iommu_setup_dma_ops(gdev->dev); mutex_unlock(&group->mutex); /* @@ -3217,18 +3220,9 @@ static ssize_t iommu_group_store_type(struct iommu_group *group, if (ret) goto out_unlock; - /* - * Release the mutex here because ops->probe_finalize() call-back of - * some vendor IOMMU drivers calls arm_iommu_attach_device() which - * in-turn might call back into IOMMU core code, where it tries to take - * group->mutex, resulting in a deadlock. - */ - mutex_unlock(&group->mutex); - /* Make sure dma_ops is appropriatley set */ for_each_group_device(group, gdev) - iommu_group_do_probe_finalize(gdev->dev); - return count; + iommu_setup_dma_ops(gdev->dev); out_unlock: mutex_unlock(&group->mutex);
On Thu, Dec 14, 2023 at 06:22:49PM +0000, Robin Murphy wrote: > Taking yet another look, there's not actually one single place we can do > this right now which will work in a manageable way for all cases. The dma ops should be set after changing the translation and there is only one place that attachs the domain? What prevents putting it there? > @@ -3217,18 +3220,9 @@ static ssize_t iommu_group_store_type(struct iommu_group *group, > if (ret) > goto out_unlock; > - /* > - * Release the mutex here because ops->probe_finalize() call-back of > - * some vendor IOMMU drivers calls arm_iommu_attach_device() which > - * in-turn might call back into IOMMU core code, where it tries to take > - * group->mutex, resulting in a deadlock. > - */ > - mutex_unlock(&group->mutex); > - > /* Make sure dma_ops is appropriatley set */ > for_each_group_device(group, gdev) > - iommu_group_do_probe_finalize(gdev->dev); > - return count; If we are turning this into something that only works for the ARM DMA then the remaining caller should be guarded by an IS_ENABLED Jason
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 3cb101e8cb29..96ff791199e8 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -58,8 +58,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, ARCH_DMA_MINALIGN, cls); dev->dma_coherent = coherent; - if (iommu) - iommu_setup_dma_ops(dev, dma_base, dma_base + size - 1); xen_setup_dma_ops(dev); } diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index fcc987f5d4ed..9418808009ba 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -1985,13 +1985,6 @@ static struct iommu_device *amd_iommu_probe_device(struct device *dev) return iommu_dev; } -static void amd_iommu_probe_finalize(struct device *dev) -{ - /* Domains are initialized for this device - have a look what we ended up with */ - set_dma_ops(dev, NULL); - iommu_setup_dma_ops(dev, 0, U64_MAX); -} - static void amd_iommu_release_device(struct device *dev) { struct amd_iommu *iommu; @@ -2646,7 +2639,6 @@ const struct iommu_ops amd_iommu_ops = { .domain_alloc_user = amd_iommu_domain_alloc_user, .probe_device = amd_iommu_probe_device, .release_device = amd_iommu_release_device, - .probe_finalize = amd_iommu_probe_finalize, .device_group = amd_iommu_device_group, .get_resv_regions = amd_iommu_get_resv_regions, .is_attach_deferred = amd_iommu_is_attach_deferred, diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 27a167f4cd3e..d808c8dcf5cb 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1724,25 +1724,20 @@ static const struct dma_map_ops iommu_dma_ops = { .opt_mapping_size = iommu_dma_opt_mapping_size, }; -/* - * The IOMMU core code allocates the default DMA domain, which the underlying - * IOMMU driver needs to support via the dma-iommu layer. - */ -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit) +void iommu_setup_dma_ops(struct device *dev) { struct iommu_domain *domain = iommu_get_domain_for_dev(dev); - if (!domain) - goto out_err; + if (dev_is_pci(dev)) + dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac; - /* - * The IOMMU core code allocates the default DMA domain, which the - * underlying IOMMU driver needs to support via the dma-iommu layer. - */ if (iommu_is_dma_domain(domain)) { if (iommu_dma_init_domain(domain, dev)) goto out_err; dev->dma_ops = &iommu_dma_ops; + } else if (dev->dma_ops == &iommu_dma_ops) { + /* Clean up if we've switched *from* a DMA domain */ + dev->dma_ops = NULL; } return; @@ -1750,7 +1745,6 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit) pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", dev_name(dev)); } -EXPORT_SYMBOL_GPL(iommu_setup_dma_ops); static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, phys_addr_t msi_addr, struct iommu_domain *domain) diff --git a/drivers/iommu/dma-iommu.h b/drivers/iommu/dma-iommu.h index c829f1f82a99..c12d63457c76 100644 --- a/drivers/iommu/dma-iommu.h +++ b/drivers/iommu/dma-iommu.h @@ -9,6 +9,8 @@ #ifdef CONFIG_IOMMU_DMA +void iommu_setup_dma_ops(struct device *dev); + int iommu_get_dma_cookie(struct iommu_domain *domain); void iommu_put_dma_cookie(struct iommu_domain *domain); @@ -17,13 +19,13 @@ int iommu_dma_init_fq(struct iommu_domain *domain); void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list); extern bool iommu_dma_forcedac; -static inline void iommu_dma_set_pci_32bit_workaround(struct device *dev) -{ - dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac; -} #else /* CONFIG_IOMMU_DMA */ +static inline void iommu_setup_dma_ops(struct device *dev) +{ +} + static inline int iommu_dma_init_fq(struct iommu_domain *domain) { return -EINVAL; @@ -42,9 +44,5 @@ static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_he { } -static inline void iommu_dma_set_pci_32bit_workaround(struct device *dev) -{ -} - #endif /* CONFIG_IOMMU_DMA */ #endif /* __DMA_IOMMU_H */ diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 3531b956556c..f7347ed41e89 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4480,12 +4480,6 @@ static void intel_iommu_release_device(struct device *dev) set_dma_ops(dev, NULL); } -static void intel_iommu_probe_finalize(struct device *dev) -{ - set_dma_ops(dev, NULL); - iommu_setup_dma_ops(dev, 0, U64_MAX); -} - static void intel_iommu_get_resv_regions(struct device *device, struct list_head *head) { @@ -4937,7 +4931,6 @@ const struct iommu_ops intel_iommu_ops = { .domain_alloc = intel_iommu_domain_alloc, .domain_alloc_user = intel_iommu_domain_alloc_user, .probe_device = intel_iommu_probe_device, - .probe_finalize = intel_iommu_probe_finalize, .release_device = intel_iommu_release_device, .get_resv_regions = intel_iommu_get_resv_regions, .device_group = intel_iommu_device_group, diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 824989874dee..43f630d0530e 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -560,10 +560,10 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list if (list_empty(&group->entry)) list_add_tail(&group->entry, group_list); } - mutex_unlock(&group->mutex); - if (dev_is_pci(dev)) - iommu_dma_set_pci_32bit_workaround(dev); + iommu_setup_dma_ops(dev); + + mutex_unlock(&group->mutex); return 0; diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c index 9a5196f523de..d8eaa7ea380b 100644 --- a/drivers/iommu/s390-iommu.c +++ b/drivers/iommu/s390-iommu.c @@ -695,11 +695,6 @@ static size_t s390_iommu_unmap_pages(struct iommu_domain *domain, return size; } -static void s390_iommu_probe_finalize(struct device *dev) -{ - iommu_setup_dma_ops(dev, 0, U64_MAX); -} - struct zpci_iommu_ctrs *zpci_get_iommu_ctrs(struct zpci_dev *zdev) { if (!zdev || !zdev->s390_domain) @@ -785,7 +780,6 @@ static const struct iommu_ops s390_iommu_ops = { .capable = s390_iommu_capable, .domain_alloc_paging = s390_domain_alloc_paging, .probe_device = s390_iommu_probe_device, - .probe_finalize = s390_iommu_probe_finalize, .release_device = s390_iommu_release_device, .device_group = generic_device_group, .pgsize_bitmap = SZ_4K, diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c index 9bcffdde6175..5a558456946b 100644 --- a/drivers/iommu/virtio-iommu.c +++ b/drivers/iommu/virtio-iommu.c @@ -998,15 +998,6 @@ static struct iommu_device *viommu_probe_device(struct device *dev) return ERR_PTR(ret); } -static void viommu_probe_finalize(struct device *dev) -{ -#ifndef CONFIG_ARCH_HAS_SETUP_DMA_OPS - /* First clear the DMA ops in case we're switching from a DMA domain */ - set_dma_ops(dev, NULL); - iommu_setup_dma_ops(dev, 0, U64_MAX); -#endif -} - static void viommu_release_device(struct device *dev) { struct viommu_endpoint *vdev = dev_iommu_priv_get(dev); @@ -1043,7 +1034,6 @@ static struct iommu_ops viommu_ops = { .capable = viommu_capable, .domain_alloc = viommu_domain_alloc, .probe_device = viommu_probe_device, - .probe_finalize = viommu_probe_finalize, .release_device = viommu_release_device, .device_group = viommu_device_group, .get_resv_regions = viommu_get_resv_regions, diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 20ed3a4fc5e0..3a3bf8afb8ca 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -1283,9 +1283,6 @@ static inline void iommu_debugfs_setup(void) {} #ifdef CONFIG_IOMMU_DMA #include <linux/msi.h> -/* Setup call for arch DMA mapping code */ -void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit); - int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base); int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr); @@ -1296,10 +1293,6 @@ void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg); struct msi_desc; struct msi_msg; -static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit) -{ -} - static inline int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base) { return -ENODEV;
It's somewhat hard to see, but arm64's arch_setup_dma_ops() should only ever call iommu_setup_dma_ops() after a successful iommu_probe_device(), which means there should be no harm in achieving the same orer of operations by running it off the back of iommu_probe_device() itself. This then puts it in line with the x86 and s390 .probe_finalize bodges, letting us pull it all into the main flow properly. As a bonus this lets us fold in and de-scope the PCI workaround setup as well. At this point we can also then pull the call inside the group mutex, and avoid having to think about whether iommu_group_store_type() could theroetically race and free the domain where iommu_setup_dma_ops() may currently run just *before* iommu_device_use_default_domain() claims it. Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- v2: Shuffle around to make sure the iommu_group_do_probe_finalize() cases are covered as well, with bonus side-effects as above. --- arch/arm64/mm/dma-mapping.c | 2 -- drivers/iommu/amd/iommu.c | 8 -------- drivers/iommu/dma-iommu.c | 18 ++++++------------ drivers/iommu/dma-iommu.h | 14 ++++++-------- drivers/iommu/intel/iommu.c | 7 ------- drivers/iommu/iommu.c | 6 +++--- drivers/iommu/s390-iommu.c | 6 ------ drivers/iommu/virtio-iommu.c | 10 ---------- include/linux/iommu.h | 7 ------- 9 files changed, 15 insertions(+), 63 deletions(-)