| Message ID | 1651947548-4055-7-git-send-email-olekstysh@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | virtio: Solution to restrict memory access under Xen using xen-grant DMA-mapping layer | expand |
On Sat, 7 May 2022, Oleksandr Tyshchenko wrote: > From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> > > Use the presence of recently introduced "xen,dev-domid" property > in the device node as a clear indicator of enabling Xen grant > mappings scheme for that device and read the ID of Xen domain where > the corresponding backend resides. The ID (domid) is used as > an argument to the Xen grant mapping APIs. > > Also introduce xen_is_grant_dma_device() to check whether xen-grant > DMA ops need to be set for a passed device. > > Remove the hardcoded domid 0 in xen_grant_setup_dma_ops(). > > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > Changes RFC -> V1: > - new patch, split required changes from commit: > "[PATCH 4/6] virtio: Various updates to xen-virtio DMA ops layer" > - update checks in xen_virtio_setup_dma_ops() to only support > DT devices for now > - remove the "virtio,mmio" check from xen_is_virtio_device() > - remane everything according to the new naming scheme: > s/virtio/grant_dma > > Changes V1 -> V2: > - remove dev_is_pci() check in xen_grant_setup_dma_ops() > - remove EXPORT_SYMBOL_GPL(xen_is_grant_dma_device); > --- > drivers/xen/grant-dma-ops.c | 24 +++++++++++++++++------- > include/xen/xen-ops.h | 5 +++++ > 2 files changed, 22 insertions(+), 7 deletions(-) > > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c > index 29ad7bf..8924178 100644 > --- a/drivers/xen/grant-dma-ops.c > +++ b/drivers/xen/grant-dma-ops.c > @@ -55,11 +55,6 @@ static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev) > * Such a DMA address is formed by using the grant reference as a frame > * number and setting the highest address bit (this bit is for the backend > * to be able to distinguish it from e.g. a mmio address). > - * > - * Note that for now we hard wire dom0 to be the backend domain. In order > - * to support any domain as backend we'd need to add a way to communicate > - * the domid of this backend, e.g. via Xenstore, via the PCI-device's > - * config space or DT/ACPI. > */ > static void *xen_grant_dma_alloc(struct device *dev, size_t size, > dma_addr_t *dma_handle, gfp_t gfp, > @@ -275,6 +270,15 @@ static const struct dma_map_ops xen_grant_dma_ops = { > .dma_supported = xen_grant_dma_supported, > }; > > +bool xen_is_grant_dma_device(struct device *dev) > +{ > + /* XXX Handle only DT devices for now */ > + if (!dev->of_node) > + return false; > + > + return of_property_read_bool(dev->of_node, "xen,dev-domid"); > +} > + > void xen_grant_setup_dma_ops(struct device *dev) > { > struct xen_grant_dma_data *data; > @@ -286,8 +290,14 @@ void xen_grant_setup_dma_ops(struct device *dev) > return; > } > > - /* XXX The dom0 is hardcoded as the backend domain for now */ > - dev_domid = 0; > + /* XXX ACPI device unsupported for now */ > + if (!dev->of_node) > + goto err; > + > + if (of_property_read_u32(dev->of_node, "xen,dev-domid", &dev_domid)) { > + dev_err(dev, "xen,dev-domid property is not present\n"); > + goto err; > + } > > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > if (!data) > diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h > index 4f9fad5..62be9dc 100644 > --- a/include/xen/xen-ops.h > +++ b/include/xen/xen-ops.h > @@ -223,10 +223,15 @@ static inline void xen_preemptible_hcall_end(void) { } > > #ifdef CONFIG_XEN_GRANT_DMA_OPS > void xen_grant_setup_dma_ops(struct device *dev); > +bool xen_is_grant_dma_device(struct device *dev); > #else > static inline void xen_grant_setup_dma_ops(struct device *dev) > { > } > +static inline bool xen_is_grant_dma_device(struct device *dev) > +{ > + return false; > +} > #endif /* CONFIG_XEN_GRANT_DMA_OPS */ > > #endif /* INCLUDE_XEN_OPS_H */ > -- > 2.7.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 29ad7bf..8924178 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -55,11 +55,6 @@ static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev) * Such a DMA address is formed by using the grant reference as a frame * number and setting the highest address bit (this bit is for the backend * to be able to distinguish it from e.g. a mmio address). - * - * Note that for now we hard wire dom0 to be the backend domain. In order - * to support any domain as backend we'd need to add a way to communicate - * the domid of this backend, e.g. via Xenstore, via the PCI-device's - * config space or DT/ACPI. */ static void *xen_grant_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, @@ -275,6 +270,15 @@ static const struct dma_map_ops xen_grant_dma_ops = { .dma_supported = xen_grant_dma_supported, }; +bool xen_is_grant_dma_device(struct device *dev) +{ + /* XXX Handle only DT devices for now */ + if (!dev->of_node) + return false; + + return of_property_read_bool(dev->of_node, "xen,dev-domid"); +} + void xen_grant_setup_dma_ops(struct device *dev) { struct xen_grant_dma_data *data; @@ -286,8 +290,14 @@ void xen_grant_setup_dma_ops(struct device *dev) return; } - /* XXX The dom0 is hardcoded as the backend domain for now */ - dev_domid = 0; + /* XXX ACPI device unsupported for now */ + if (!dev->of_node) + goto err; + + if (of_property_read_u32(dev->of_node, "xen,dev-domid", &dev_domid)) { + dev_err(dev, "xen,dev-domid property is not present\n"); + goto err; + } data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index 4f9fad5..62be9dc 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -223,10 +223,15 @@ static inline void xen_preemptible_hcall_end(void) { } #ifdef CONFIG_XEN_GRANT_DMA_OPS void xen_grant_setup_dma_ops(struct device *dev); +bool xen_is_grant_dma_device(struct device *dev); #else static inline void xen_grant_setup_dma_ops(struct device *dev) { } +static inline bool xen_is_grant_dma_device(struct device *dev) +{ + return false; +} #endif /* CONFIG_XEN_GRANT_DMA_OPS */ #endif /* INCLUDE_XEN_OPS_H */