From: Manish Honap <[email protected]> This commit provides an opt-out mechanism to disable the CXL support from vfio module. The opt-out is provided both build time and module load time.
Build time option CONFIG_VFIO_CXL_CORE is used to enable/disable CXL support in vfio-pci module. For runtime disabling the CXL support, use the module parameter disable_cxl. This is a per-device opt-out on the core device set by the driver before registration. Signed-off-by: Manish Honap <[email protected]> --- drivers/vfio/pci/cxl/vfio_cxl_core.c | 4 ++++ drivers/vfio/pci/vfio_pci.c | 9 +++++++++ include/linux/vfio_pci_core.h | 1 + 3 files changed, 14 insertions(+) diff --git a/drivers/vfio/pci/cxl/vfio_cxl_core.c b/drivers/vfio/pci/cxl/vfio_cxl_core.c index 46430cbfa962..3ffc3e593d04 100644 --- a/drivers/vfio/pci/cxl/vfio_cxl_core.c +++ b/drivers/vfio/pci/cxl/vfio_cxl_core.c @@ -479,6 +479,10 @@ void vfio_pci_cxl_detect_and_init(struct vfio_pci_core_device *vdev) u16 dvsec; int ret; + /* Honor the user opt-out decision */ + if (vdev->disable_cxl) + return; + if (!pcie_is_cxl(pdev)) return; diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 22cf9ea831f9..a6b0fb882b9f 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -60,6 +60,12 @@ static bool disable_denylist; module_param(disable_denylist, bool, 0444); MODULE_PARM_DESC(disable_denylist, "Disable use of device denylist. Disabling the denylist allows binding to devices with known errata that may lead to exploitable stability or security issues when accessed by untrusted users."); +#if IS_ENABLED(CONFIG_VFIO_CXL_CORE) +static bool disable_cxl; +module_param(disable_cxl, bool, 0444); +MODULE_PARM_DESC(disable_cxl, "Disable CXL Type-2 extensions for all devices bound to vfio-pci. Variant drivers may instead set vdev->disable_cxl in their probe for per-device control without needing this parameter."); +#endif + static bool vfio_pci_dev_in_denylist(struct pci_dev *pdev) { switch (pdev->vendor) { @@ -189,6 +195,9 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) return PTR_ERR(vdev); dev_set_drvdata(&pdev->dev, vdev); +#if IS_ENABLED(CONFIG_VFIO_CXL_CORE) + vdev->disable_cxl = disable_cxl; +#endif vdev->pci_ops = &vfio_pci_dev_ops; ret = vfio_pci_core_register_device(vdev); if (ret) diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index aa159d0c8da7..48dc69df52fa 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -130,6 +130,7 @@ struct vfio_pci_core_device { bool needs_pm_restore:1; bool pm_intx_masked:1; bool pm_runtime_engaged:1; + bool disable_cxl:1; struct pci_saved_state *pci_saved_state; struct pci_saved_state *pm_save; int ioeventfds_nr; -- 2.25.1
