| Message ID | 20221025162004.8501-3-olekstysh@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | dfb7280225e8d965cbc46dbbaf23061388a0ff85 |
| Headers | show |
| Series | xen/virtio: Handle PCI devices which Host controller is described in DT | expand |
On 10/25/22 19:20, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > Use the same "xen-grant-dma" device concept for the PCI devices > behind device-tree based PCI Host controller, but with one modification. > Unlike for platform devices, we cannot use generic IOMMU bindings > (iommus property), as we need to support more flexible configuration. > The problem is that PCI devices under the single PCI Host controller > may have the backends running in different Xen domains and thus have > different endpoints ID (backend domains ID). > > Add ability to deal with generic PCI-IOMMU bindings (iommu-map/ > iommu-map-mask properties) which allows us to describe relationship > between PCI devices and backend domains ID properly. > > To avoid having to look up for the PCI Host bridge twice and reduce > the amount of checks pass an extra struct device_node *np to > xen_dt_grant_init_backend_domid(). > > So with current patch the code expects iommus property for the platform > devices and iommu-map/iommu-map-mask properties for PCI devices. > > The example of generated by the toolstack iommu-map property > for two PCI devices 0000:00:01.0 and 0000:00:02.0 whose > backends are running in different Xen domains with IDs 1 and 2 > respectively: > iommu-map = <0x08 0xfde9 0x01 0x08 0x10 0xfde9 0x02 0x08>; > > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Xenia Ragiadakou <burzalodowa@gmail.com> > --- > Slightly RFC. This is needed to support Xen grant mappings for virtio-pci devices > on Arm at some point in the future. The Xen toolstack side is not completely ready yet. > Here, for PCI devices we use more flexible way to pass backend domid to the guest > than for platform devices. > > Changes V1 -> V2: > - update commit description > - rebase > - rework to use generic PCI-IOMMU bindings instead of generic IOMMU bindings > > Changes V2 -> V3: > - update commit description, add an example > - drop xen_dt_map_id() and squash xen_dt_get_pci_host_node() with > xen_dt_get_node() > - pass struct device_node *np to xen_is_dt_grant_dma_device() and > xen_dt_grant_init_backend_domid() > - pass domid_t *backend_domid instead of struct xen_grant_dma_data *data > to xen_dt_grant_init_backend_domid() > > Changes V3 -> V4: > - just rebase on new prereq patch > "xen/virtio: Optimize the setup of "xen-grant-dma" devices" > > Previous discussion is at: > https://lore.kernel.org/xen-devel/20221006174804.2003029-1-olekstysh@gmail.com/ > https://lore.kernel.org/xen-devel/20221015153409.918775-1-olekstysh@gmail.com/ > https://lore.kernel.org/xen-devel/20221021172408.77397-1-olekstysh@gmail.com/ > > Based on: > https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git/log/?h=for-linus-6.1 > --- > --- > drivers/xen/grant-dma-ops.c | 46 +++++++++++++++++++++++++++++++------ > 1 file changed, 39 insertions(+), 7 deletions(-) > > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c > index 1e797a043980..9784a77fa3c9 100644 > --- a/drivers/xen/grant-dma-ops.c > +++ b/drivers/xen/grant-dma-ops.c > @@ -10,6 +10,7 @@ > #include <linux/module.h> > #include <linux/dma-map-ops.h> > #include <linux/of.h> > +#include <linux/pci.h> > #include <linux/pfn.h> > #include <linux/xarray.h> > #include <linux/virtio_anchor.h> > @@ -292,15 +293,43 @@ static const struct dma_map_ops xen_grant_dma_ops = { > .dma_supported = xen_grant_dma_supported, > }; > > +static struct device_node *xen_dt_get_node(struct device *dev) > +{ > + if (dev_is_pci(dev)) { > + struct pci_dev *pdev = to_pci_dev(dev); > + struct pci_bus *bus = pdev->bus; > + > + /* Walk up to the root bus to look for PCI Host controller */ > + while (!pci_is_root_bus(bus)) > + bus = bus->parent; > + > + return of_node_get(bus->bridge->parent->of_node); > + } > + > + return of_node_get(dev->of_node); > +} > + > static int xen_dt_grant_init_backend_domid(struct device *dev, > + struct device_node *np, > domid_t *backend_domid) > { > - struct of_phandle_args iommu_spec; > + struct of_phandle_args iommu_spec = { .args_count = 1 }; > > - if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", > - 0, &iommu_spec)) { > - dev_dbg(dev, "Cannot parse iommus property\n"); > - return -ESRCH; > + if (dev_is_pci(dev)) { > + struct pci_dev *pdev = to_pci_dev(dev); > + u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn); > + > + if (of_map_id(np, rid, "iommu-map", "iommu-map-mask", &iommu_spec.np, > + iommu_spec.args)) { > + dev_dbg(dev, "Cannot translate ID\n"); > + return -ESRCH; > + } > + } else { > + if (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", > + 0, &iommu_spec)) { > + dev_dbg(dev, "Cannot parse iommus property\n"); > + return -ESRCH; > + } > } > > if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || > @@ -324,10 +353,13 @@ static int xen_dt_grant_init_backend_domid(struct device *dev, > static int xen_grant_init_backend_domid(struct device *dev, > domid_t *backend_domid) > { > + struct device_node *np; > int ret = -ENODEV; > > - if (dev->of_node) { > - ret = xen_dt_grant_init_backend_domid(dev, backend_domid); > + np = xen_dt_get_node(dev); > + if (np) { > + ret = xen_dt_grant_init_backend_domid(dev, np, backend_domid); > + of_node_put(np); > } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) { > dev_info(dev, "Using dom0 as backend\n"); > *backend_domid = 0;
On Tue, 25 Oct 2022, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > Use the same "xen-grant-dma" device concept for the PCI devices > behind device-tree based PCI Host controller, but with one modification. > Unlike for platform devices, we cannot use generic IOMMU bindings > (iommus property), as we need to support more flexible configuration. > The problem is that PCI devices under the single PCI Host controller > may have the backends running in different Xen domains and thus have > different endpoints ID (backend domains ID). > > Add ability to deal with generic PCI-IOMMU bindings (iommu-map/ > iommu-map-mask properties) which allows us to describe relationship > between PCI devices and backend domains ID properly. > > To avoid having to look up for the PCI Host bridge twice and reduce > the amount of checks pass an extra struct device_node *np to > xen_dt_grant_init_backend_domid(). > > So with current patch the code expects iommus property for the platform > devices and iommu-map/iommu-map-mask properties for PCI devices. > > The example of generated by the toolstack iommu-map property > for two PCI devices 0000:00:01.0 and 0000:00:02.0 whose > backends are running in different Xen domains with IDs 1 and 2 > respectively: > iommu-map = <0x08 0xfde9 0x01 0x08 0x10 0xfde9 0x02 0x08>; > > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > Slightly RFC. This is needed to support Xen grant mappings for virtio-pci devices > on Arm at some point in the future. The Xen toolstack side is not completely ready yet. > Here, for PCI devices we use more flexible way to pass backend domid to the guest > than for platform devices. > > Changes V1 -> V2: > - update commit description > - rebase > - rework to use generic PCI-IOMMU bindings instead of generic IOMMU bindings > > Changes V2 -> V3: > - update commit description, add an example > - drop xen_dt_map_id() and squash xen_dt_get_pci_host_node() with > xen_dt_get_node() > - pass struct device_node *np to xen_is_dt_grant_dma_device() and > xen_dt_grant_init_backend_domid() > - pass domid_t *backend_domid instead of struct xen_grant_dma_data *data > to xen_dt_grant_init_backend_domid() > > Changes V3 -> V4: > - just rebase on new prereq patch > "xen/virtio: Optimize the setup of "xen-grant-dma" devices" > > Previous discussion is at: > https://lore.kernel.org/xen-devel/20221006174804.2003029-1-olekstysh@gmail.com/ > https://lore.kernel.org/xen-devel/20221015153409.918775-1-olekstysh@gmail.com/ > https://lore.kernel.org/xen-devel/20221021172408.77397-1-olekstysh@gmail.com/ > > Based on: > https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git/log/?h=for-linus-6.1 > --- > --- > drivers/xen/grant-dma-ops.c | 46 +++++++++++++++++++++++++++++++------ > 1 file changed, 39 insertions(+), 7 deletions(-) > > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c > index 1e797a043980..9784a77fa3c9 100644 > --- a/drivers/xen/grant-dma-ops.c > +++ b/drivers/xen/grant-dma-ops.c > @@ -10,6 +10,7 @@ > #include <linux/module.h> > #include <linux/dma-map-ops.h> > #include <linux/of.h> > +#include <linux/pci.h> > #include <linux/pfn.h> > #include <linux/xarray.h> > #include <linux/virtio_anchor.h> > @@ -292,15 +293,43 @@ static const struct dma_map_ops xen_grant_dma_ops = { > .dma_supported = xen_grant_dma_supported, > }; > > +static struct device_node *xen_dt_get_node(struct device *dev) > +{ > + if (dev_is_pci(dev)) { > + struct pci_dev *pdev = to_pci_dev(dev); > + struct pci_bus *bus = pdev->bus; > + > + /* Walk up to the root bus to look for PCI Host controller */ > + while (!pci_is_root_bus(bus)) > + bus = bus->parent; > + > + return of_node_get(bus->bridge->parent->of_node); > + } > + > + return of_node_get(dev->of_node); > +} > + > static int xen_dt_grant_init_backend_domid(struct device *dev, > + struct device_node *np, > domid_t *backend_domid) > { > - struct of_phandle_args iommu_spec; > + struct of_phandle_args iommu_spec = { .args_count = 1 }; > > - if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", > - 0, &iommu_spec)) { > - dev_dbg(dev, "Cannot parse iommus property\n"); > - return -ESRCH; > + if (dev_is_pci(dev)) { > + struct pci_dev *pdev = to_pci_dev(dev); > + u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn); > + > + if (of_map_id(np, rid, "iommu-map", "iommu-map-mask", &iommu_spec.np, > + iommu_spec.args)) { > + dev_dbg(dev, "Cannot translate ID\n"); > + return -ESRCH; > + } > + } else { > + if (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", > + 0, &iommu_spec)) { > + dev_dbg(dev, "Cannot parse iommus property\n"); > + return -ESRCH; > + } > } > > if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || > @@ -324,10 +353,13 @@ static int xen_dt_grant_init_backend_domid(struct device *dev, > static int xen_grant_init_backend_domid(struct device *dev, > domid_t *backend_domid) > { > + struct device_node *np; > int ret = -ENODEV; > > - if (dev->of_node) { > - ret = xen_dt_grant_init_backend_domid(dev, backend_domid); > + np = xen_dt_get_node(dev); > + if (np) { > + ret = xen_dt_grant_init_backend_domid(dev, np, backend_domid); > + of_node_put(np); > } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) { > dev_info(dev, "Using dom0 as backend\n"); > *backend_domid = 0; > -- > 2.25.1 >
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 1e797a043980..9784a77fa3c9 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -10,6 +10,7 @@ #include <linux/module.h> #include <linux/dma-map-ops.h> #include <linux/of.h> +#include <linux/pci.h> #include <linux/pfn.h> #include <linux/xarray.h> #include <linux/virtio_anchor.h> @@ -292,15 +293,43 @@ static const struct dma_map_ops xen_grant_dma_ops = { .dma_supported = xen_grant_dma_supported, }; +static struct device_node *xen_dt_get_node(struct device *dev) +{ + if (dev_is_pci(dev)) { + struct pci_dev *pdev = to_pci_dev(dev); + struct pci_bus *bus = pdev->bus; + + /* Walk up to the root bus to look for PCI Host controller */ + while (!pci_is_root_bus(bus)) + bus = bus->parent; + + return of_node_get(bus->bridge->parent->of_node); + } + + return of_node_get(dev->of_node); +} + static int xen_dt_grant_init_backend_domid(struct device *dev, + struct device_node *np, domid_t *backend_domid) { - struct of_phandle_args iommu_spec; + struct of_phandle_args iommu_spec = { .args_count = 1 }; - if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", - 0, &iommu_spec)) { - dev_dbg(dev, "Cannot parse iommus property\n"); - return -ESRCH; + if (dev_is_pci(dev)) { + struct pci_dev *pdev = to_pci_dev(dev); + u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn); + + if (of_map_id(np, rid, "iommu-map", "iommu-map-mask", &iommu_spec.np, + iommu_spec.args)) { + dev_dbg(dev, "Cannot translate ID\n"); + return -ESRCH; + } + } else { + if (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", + 0, &iommu_spec)) { + dev_dbg(dev, "Cannot parse iommus property\n"); + return -ESRCH; + } } if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || @@ -324,10 +353,13 @@ static int xen_dt_grant_init_backend_domid(struct device *dev, static int xen_grant_init_backend_domid(struct device *dev, domid_t *backend_domid) { + struct device_node *np; int ret = -ENODEV; - if (dev->of_node) { - ret = xen_dt_grant_init_backend_domid(dev, backend_domid); + np = xen_dt_get_node(dev); + if (np) { + ret = xen_dt_grant_init_backend_domid(dev, np, backend_domid); + of_node_put(np); } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) { dev_info(dev, "Using dom0 as backend\n"); *backend_domid = 0;