[I am not subscribed to linux-efi. Sorry for the bad threading. Please include
me on the cc on any replies.]
Matt, I grabbed your patches which are similar to a change that I wanted to make
to the kernel. There is one issue though that I want to bring up.
With or without your changeset, I see the following issue on Dell system with a
valid ESRT table.
[ 0.000000] efi: SMBIOS=0x8ce95000 ACPI=0x8d2fe000 ACPI 2.0=0x8d2fe014
ESRT=0x8d0f5000 MPS=0x8d0dd000
[ 0.000000] efi: requested map not found.
[ 0.000000] esrt: ESRT header is not in the memory map.
[ 0.000000] SMBIOS 2.8 present.
This occurs AFAICT (with or without your changes) because of this check in
efi_mem_desc_lookup():
if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
md->type != EFI_BOOT_SERVICES_DATA &&
md->type != EFI_RUNTIME_SERVICES_DATA) {
continue;
}
which then results in skipping the appropriate region. IIUC (and that's part of
my question ;)) the above check means that the region has already been
permanently mapped. That is,
rc = efi_mem_desc_lookup(efi.esrt, &md);
if (rc < 0) {
pr_err("ESRT header is not in the memory map.\n");
return;
}
...
va = early_memremap(efi.esrt, size);
if (!va) {
and rc is -ENOENT because a matching region couldn't be found. As can be seen
the existing ESRT code will attempt to remap the region if not mapped.
I think that perhaps the function should be changed to do
for_each_efi_memory_desc(md) {
u64 size;
u64 end;
size = md->num_pages << EFI_PAGE_SHIFT;
end = md->phys_addr + size;
if (phys_addr >= md->phys_addr && phys_addr < end) {
memcpy(out_md, md, sizeof(*out_md));
if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
md->type != EFI_BOOT_SERVICES_DATA &&
md->type != EFI_RUNTIME_SERVICES_DATA) {
return UNMAPPED;
}
return MAPPED;
}
}
so that individual callers (like the ESRT code) can then make a decision on
whether or not the area needs to be mapped.
Thoughts/concerns?
P.
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