On 12/03/19 at 10:11pm, Michael Weiser wrote: > Hi Dave, > > On Tue, Dec 03, 2019 at 07:54:35PM +0800, Dave Young wrote: > > > > Neither adding add_efi_memmap nor adding your patch and setting that option > > > does make the ESRT memory region appear in /proc/iomem. kexec_file still > > > loads the kernel across the ESRT region. > > Hmm, sorry, my bad, actuall add_efi_memmap does not consider the > > EFI_MEMORY_RUNTIME attribute, it only reads the memory descriptor types. > > > Will read your replied information later, did not get time today, but > > probably below chunk can help? > > > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c > > index 3b9fd679cea9..516307617621 100644 > > --- a/arch/x86/platform/efi/quirks.c > > +++ b/arch/x86/platform/efi/quirks.c > > @@ -293,6 +293,8 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size) > > early_memunmap(new, new_size); > > > efi_memmap_install(new_phys, num_entries); > > + e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED); > > + e820__update_table(e820_table); > > } > > > /* > > Yes, that did it: > > 00000000-00000fff : Reserved > 00001000-0009efff : System RAM > 0009f000-000fffff : Reserved > 000a0000-000bffff : PCI Bus 0000:00 > 000e0000-000e3fff : PCI Bus 0000:00 > 000e4000-000e7fff : PCI Bus 0000:00 > 000e8000-000ebfff : PCI Bus 0000:00 > 000ec000-000effff : PCI Bus 0000:00 > 000f0000-000fffff : PCI Bus 0000:00 > 000f0000-000fffff : System ROM > 00100000-74dd1fff : System RAM > 65000000-6affffff : Crash kernel > 74dd2000-74dd2fff : Reserved <----- ESRT > 74dd3000-763f5fff : System RAM > 763f6000-79974fff : Reserved > 79975000-799f1fff : ACPI Tables > 799f2000-79aa6fff : ACPI Non-volatile Storage > 79a17000-79a17fff : USBC000:00 Ok, good to know it works. I will think about it and file a patch later. There are more things to consider, eg. kexec reboot multiple times, userspace kexec loader etc. If we choose to fix it in kexec_file path to avoid those region then we need to do same in userspace, there will be compatibility issues so I would still prefer to go with this way you tested. BTW, on my laptop the ESRT stays in EFI runtime area so I do not see the problem. This should be machine/firmware specific. Here is the info on my laptop: [ 0.000000] efi: mem34: [Runtime Data |RUN| | | | | | | |WB|WT|WC|UC] range=[0x000000007a4b0000-0x000000007a676fff] (1MB) [ 0.020670] esrt: Reserving ESRT space from 0x000000007a4ec000 to 0x000000007a4ec088. Thanks Dave
