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| author | Saurabh Sengar <ssengar@linux.microsoft.com> | 2023-11-11 00:37:47 -0800 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2023-11-12 22:50:30 +0000 |
| commit | 7e8037b099c0bbe8f2109dc452dbcab8d400fc53 (patch) | |
| tree | e0726a05f9646086ec6d1fd72cb0c7d3d9a3a3cd /arch | |
| parent | c3803203bc5ec910a3eb06172cf6fb368e0e4390 (diff) | |
x86/hyperv: Fix the detection of E820_TYPE_PRAM in a Gen2 VM
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@linux.microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1699691867-9827-1-git-send-email-ssengar@linux.microsoft.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/hyperv/hv_init.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 21556ad87f4b..8f3a4d16bb79 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -15,6 +15,7 @@ #include <linux/io.h> #include <asm/apic.h> #include <asm/desc.h> +#include <asm/e820/api.h> #include <asm/sev.h> #include <asm/ibt.h> #include <asm/hypervisor.h> @@ -286,15 +287,31 @@ static int hv_cpu_die(unsigned int cpu) static int __init hv_pci_init(void) { - int gen2vm = efi_enabled(EFI_BOOT); + bool gen2vm = efi_enabled(EFI_BOOT); /* - * For Generation-2 VM, we exit from pci_arch_init() by returning 0. - * The purpose is to suppress the harmless warning: + * A Generation-2 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() here: e820__reserve_resources_late() + * depends on e820__reserve_resources(), which has been called earlier + * from setup_arch(). Note: e820__reserve_resources_late() 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. + * + * We return 0 here so that pci_arch_init() won't print the warning: * "PCI: Fatal: No config space access function found" */ - if (gen2vm) + if (gen2vm) { + e820__reserve_resources_late(); return 0; + } /* For Generation-1 VM, we'll proceed in pci_arch_init(). */ return 1; |