On Sat, Nov 11, 2023 at 12:37:47AM -0800, Saurabh Sengar wrote: > A Gen2 VM doesn't support legacy PCI/PCIe, so both raw_pci_ops and > raw_pci_ext_ops are NULL, and pci_subsys_init() -> pcibios_init() > doesn't call pcibios_resource_survey() -> e820__reserve_resources_late(); > as a result, any emulated persistent memory of E820_TYPE_PRAM (12) via > the kernel parameter memmap=nn[KMG]!ss is not added into iomem_resource > and hence can't be detected by register_e820_pmem(). > > Fix this by directly calling e820__reserve_resources_late() in > hv_pci_init(), which is called from arch_initcall(pci_arch_init). > > It's ok to move a Gen2 VM's e820__reserve_resources_late() from > subsys_initcall(pci_subsys_init) to arch_initcall(pci_arch_init) because > the code in-between doesn't depend on the E820 resources. > e820__reserve_resources_late() depends on e820__reserve_resources(), > which has been called earlier from setup_arch(). > > For a Gen-2 VM, the new hv_pci_init() also adds any memory of > E820_TYPE_PMEM (7) into iomem_resource, and acpi_nfit_register_region() -> > acpi_nfit_insert_resource() -> region_intersects() returns > REGION_INTERSECTS, so the memory of E820_TYPE_PMEM won't get added twice. > > Changed the local variable "int gen2vm" to "bool gen2vm". > > Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> Applied to hyperv-fixes. Thanks.
