From: Manish Honap <[email protected]> cxl_map_component_regs() claims each mapped sub-block with devm_request_mem_region(). A driver that owns the whole component register BAR, such as vfio-cxl, has already claimed the full BAR, so the per-sub-block claim collides and the mapping fails.
Add a bar_owned parameter to cxl_pci_setup_regs() and record it in skip_sub_bar_request on the register map. When set, cxl-core maps the sub-block without requesting the region and leaves ownership with the upper driver. cxl_pci passes false and keeps its existing claim, preserving /dev/mem tooling access to the rest of the component space. Signed-off-by: Manish Honap <[email protected]> --- drivers/cxl/core/pci.c | 9 ++++++++- drivers/cxl/core/regs.c | 32 ++++++++++++++++++++++---------- drivers/cxl/pci.c | 4 ++-- include/cxl/cxl.h | 3 +++ include/cxl/pci.h | 2 +- 5 files changed, 36 insertions(+), 14 deletions(-) diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 9d807c1a002c..08d4c955137d 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -720,7 +720,7 @@ static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev, } int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type, - struct cxl_register_map *map) + struct cxl_register_map *map, bool bar_owned) { int rc; @@ -750,6 +750,13 @@ int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type, return rc; } + /* + * A caller that owns the whole register BAR (for example vfio-cxl) + * maps the sub-blocks without claiming them, so the later + * cxl_map_component_regs() does not collide with the full-BAR request. + */ + map->skip_sub_bar_request = bar_owned; + return cxl_setup_regs(map); } EXPORT_SYMBOL_NS_GPL(cxl_pci_setup_regs, "CXL"); diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c index 989e79383b99..90dd85f322f5 100644 --- a/drivers/cxl/core/regs.c +++ b/drivers/cxl/core/regs.c @@ -177,35 +177,47 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base, } EXPORT_SYMBOL_NS_GPL(cxl_probe_device_regs, "CXL"); -void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr, - resource_size_t length) +static void __iomem *__cxl_iomap_block(struct device *dev, resource_size_t addr, + resource_size_t length, bool request) { + resource_size_t end = addr + length - 1; void __iomem *ret_val; struct resource *res; if (WARN_ON_ONCE(addr == CXL_RESOURCE_NONE)) return NULL; - res = devm_request_mem_region(dev, addr, length, dev_name(dev)); - if (!res) { - resource_size_t end = addr + length - 1; - - dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end); - return NULL; + /* + * An owning driver (e.g. vfio-cxl) may already hold the whole BAR; a + * sub-block request would then collide with that claim. + */ + if (request) { + res = devm_request_mem_region(dev, addr, length, dev_name(dev)); + if (!res) { + dev_err(dev, "Failed to request region %pa-%pa\n", &addr, &end); + return NULL; + } } ret_val = devm_ioremap(dev, addr, length); if (!ret_val) - dev_err(dev, "Failed to map region %pr\n", res); + dev_err(dev, "Failed to map region %pa-%pa\n", &addr, &end); return ret_val; } + +void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr, + resource_size_t length) +{ + return __cxl_iomap_block(dev, addr, length, true); +} EXPORT_SYMBOL_NS_GPL(devm_cxl_iomap_block, "CXL"); int cxl_map_component_regs(const struct cxl_register_map *map, struct cxl_component_regs *regs, unsigned long map_mask) { + bool request = !map->skip_sub_bar_request; struct device *host = map->host; struct mapinfo { const struct cxl_reg_map *rmap; @@ -227,7 +239,7 @@ int cxl_map_component_regs(const struct cxl_register_map *map, continue; addr = map->resource + mi->rmap->offset; length = mi->rmap->size; - *(mi->addr) = devm_cxl_iomap_block(host, addr, length); + *(mi->addr) = __cxl_iomap_block(host, addr, length, request); if (!*(mi->addr)) return -ENOMEM; } diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index bb892dbfdd6d..ec1693c21f61 100644 --- a/drivers/cxl/pci.c +++ b/drivers/cxl/pci.c @@ -816,7 +816,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) cxlds->rcd = is_cxl_restricted(pdev); - rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map); + rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map, false); if (rc) return rc; @@ -829,7 +829,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) * still be useful for management functions so don't return an error. */ rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT, - &cxlds->reg_map); + &cxlds->reg_map, false); if (rc) dev_warn(&pdev->dev, "No component registers (%d)\n", rc); else if (!cxlds->reg_map.component_map.ras.valid) diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h index efb8ac97bd92..f8e8fddba152 100644 --- a/include/cxl/cxl.h +++ b/include/cxl/cxl.h @@ -213,6 +213,8 @@ struct cxl_pmu_reg_map { * @resource: physical resource base of the register block * @max_size: maximum mapping size to perform register search * @reg_type: see enum cxl_regloc_type + * @skip_sub_bar_request: set via cxl_pci_setup_regs(); the owning driver holds + * the BAR, so skip the sub-block claim * @component_map: cxl_reg_map for component registers * @device_map: cxl_reg_maps for device registers * @pmu_map: cxl_reg_maps for CXL Performance Monitoring Units @@ -223,6 +225,7 @@ struct cxl_register_map { resource_size_t resource; resource_size_t max_size; u8 reg_type; + bool skip_sub_bar_request; union { struct cxl_component_reg_map component_map; struct cxl_device_reg_map device_map; diff --git a/include/cxl/pci.h b/include/cxl/pci.h index 3e0000015871..81a32004a604 100644 --- a/include/cxl/pci.h +++ b/include/cxl/pci.h @@ -18,5 +18,5 @@ struct cxl_register_map; struct pci_dev; int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type, - struct cxl_register_map *map); + struct cxl_register_map *map, bool bar_owned); #endif -- 2.25.1
