On Thu, 31 Mar 2022, Vishal Verma wrote:
The CXL specification does not define any additional constraints on the hotplug flow beyond PCIe native hotplug, so a kernel that supports native PCIe hotplug, supports CXL hotplug.
Hmm but from a Linux-pov does it make sense to allow hotplug support if the MM cannot handle it? @@ -531,7 +518,8 @@ static u32 calculate_cxl_support(void) support = OSC_CXL_2_0_PORT_DEV_REG_ACCESS_SUPPORT; if (pci_aer_available()) support |= OSC_CXL_PROTOCOL_ERR_REPORTING_SUPPORT; - if (IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)) + if (IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE) && + IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) support |= OSC_CXL_NATIVE_HP_SUPPORT; return support; After all, per the CXL 2.0 Type 3 device Hot-Add flow: "" 7. CXL aware software notifies OS memory manager about the new memory and its attributes such as latency and bandwidth. Memory manager processes a request and adds the new memory to its allocation pool. "" Thanks, Davidlohr
