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author | Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> | 2022-10-25 19:20:03 +0300 |
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committer | Juergen Gross <jgross@suse.com> | 2022-12-05 12:59:49 +0100 |
commit | 035e3a4321f73c352b6408ec2153fa5bc3feb459 (patch) | |
tree | b4316270fadbeb589707275cbd607dda71a70e1d /drivers | |
parent | 76dcd734eca23168cb008912c0f69ff408905235 (diff) | |
download | linux-035e3a4321f73c352b6408ec2153fa5bc3feb459.tar.gz linux-035e3a4321f73c352b6408ec2153fa5bc3feb459.tar.bz2 linux-035e3a4321f73c352b6408ec2153fa5bc3feb459.zip |
xen/virtio: Optimize the setup of "xen-grant-dma" devices
This is needed to avoid having to parse the same device-tree
several times for a given device.
For this to work we need to install the xen_virtio_restricted_mem_acc
callback in Arm's xen_guest_init() which is same callback as x86's
PV and HVM modes already use and remove the manual assignment in
xen_setup_dma_ops(). Also we need to split the code to initialize
backend_domid into a separate function.
Prior to current patch we parsed the device-tree three times:
1. xen_setup_dma_ops()->...->xen_is_dt_grant_dma_device()
2. xen_setup_dma_ops()->...->xen_dt_grant_init_backend_domid()
3. xen_virtio_mem_acc()->...->xen_is_dt_grant_dma_device()
With current patch we parse the device-tree only once in
xen_virtio_restricted_mem_acc()->...->xen_dt_grant_init_backend_domid()
Other benefits are:
- Not diverge from x86 when setting up Xen grant DMA ops
- Drop several global functions
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20221025162004.8501-2-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/xen/grant-dma-ops.c | 77 |
1 files changed, 28 insertions, 49 deletions
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index daa525df7bdc..1e797a043980 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -292,50 +292,20 @@ static const struct dma_map_ops xen_grant_dma_ops = { .dma_supported = xen_grant_dma_supported, }; -static bool xen_is_dt_grant_dma_device(struct device *dev) -{ - struct device_node *iommu_np; - bool has_iommu; - - iommu_np = of_parse_phandle(dev->of_node, "iommus", 0); - has_iommu = iommu_np && - of_device_is_compatible(iommu_np, "xen,grant-dma"); - of_node_put(iommu_np); - - return has_iommu; -} - -bool xen_is_grant_dma_device(struct device *dev) -{ - /* XXX Handle only DT devices for now */ - if (dev->of_node) - return xen_is_dt_grant_dma_device(dev); - - return false; -} - -bool xen_virtio_mem_acc(struct virtio_device *dev) -{ - if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) - return true; - - return xen_is_grant_dma_device(dev->dev.parent); -} - static int xen_dt_grant_init_backend_domid(struct device *dev, - struct xen_grant_dma_data *data) + domid_t *backend_domid) { struct of_phandle_args iommu_spec; if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells", 0, &iommu_spec)) { - dev_err(dev, "Cannot parse iommus property\n"); + dev_dbg(dev, "Cannot parse iommus property\n"); return -ESRCH; } if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") || iommu_spec.args_count != 1) { - dev_err(dev, "Incompatible IOMMU node\n"); + dev_dbg(dev, "Incompatible IOMMU node\n"); of_node_put(iommu_spec.np); return -ESRCH; } @@ -346,12 +316,28 @@ static int xen_dt_grant_init_backend_domid(struct device *dev, * The endpoint ID here means the ID of the domain where the * corresponding backend is running */ - data->backend_domid = iommu_spec.args[0]; + *backend_domid = iommu_spec.args[0]; return 0; } -void xen_grant_setup_dma_ops(struct device *dev) +static int xen_grant_init_backend_domid(struct device *dev, + domid_t *backend_domid) +{ + int ret = -ENODEV; + + if (dev->of_node) { + ret = xen_dt_grant_init_backend_domid(dev, backend_domid); + } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT) || xen_pv_domain()) { + dev_info(dev, "Using dom0 as backend\n"); + *backend_domid = 0; + ret = 0; + } + + return ret; +} + +static void xen_grant_setup_dma_ops(struct device *dev, domid_t backend_domid) { struct xen_grant_dma_data *data; @@ -365,16 +351,7 @@ void xen_grant_setup_dma_ops(struct device *dev) if (!data) goto err; - if (dev->of_node) { - if (xen_dt_grant_init_backend_domid(dev, data)) - goto err; - } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) { - dev_info(dev, "Using dom0 as backend\n"); - data->backend_domid = 0; - } else { - /* XXX ACPI device unsupported for now */ - goto err; - } + data->backend_domid = backend_domid; if (store_xen_grant_dma_data(dev, data)) { dev_err(dev, "Cannot store Xen grant DMA data\n"); @@ -392,12 +369,14 @@ err: bool xen_virtio_restricted_mem_acc(struct virtio_device *dev) { - bool ret = xen_virtio_mem_acc(dev); + domid_t backend_domid; - if (ret) - xen_grant_setup_dma_ops(dev->dev.parent); + if (!xen_grant_init_backend_domid(dev->dev.parent, &backend_domid)) { + xen_grant_setup_dma_ops(dev->dev.parent, backend_domid); + return true; + } - return ret; + return false; } MODULE_DESCRIPTION("Xen grant DMA-mapping layer"); |