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Subject[PATCH v2 0/4] efi: Fix handling of multiple efi_fake_mem= entries
Changes since v1 [1]:
- Add support for garbage collecting idle efi_memmap_alloc() allocations

- As Dave noticed the same problem of calling efi_memmap_split_count()
multiple times with the old map also applies to efi_memmap_insert().
Update efi_fake_memmap() to invoke efi_memmap_install() after every
efi_memmap_insert() call.



Copied from patch4:

Dave noticed that when specifying multiple efi_fake_mem= entries only
the last entry was successfully being reflected in the efi memory map.
This is due to the fact that the efi_memmap_insert() is being called
multiple times, but on successive invocations the insertion should be
applied to the last new memmap rather than the original map at
efi_fake_memmap() entry.

Rework efi_fake_memmap() to install the new memory map after each
efi_fake_mem= entry is parsed.

This also fixes an issue in efi_fake_memmap() that caused it to litter
emtpy entries into the end of the efi memory map. The empty entry causes
efi_memmap_insert() to attempt more memmap splits / copies than
efi_memmap_split_count() accounted for when sizing the new map.

BUG: unable to handle page fault for address: ffffffffff281000
RIP: 0010:efi_memmap_insert+0x11d/0x191
Call Trace:
? bgrt_init+0xbe/0xbe
? efi_arch_mem_reserve+0x1cb/0x228
? acpi_parse_bgrt+0xa/0xd
? acpi_table_parse+0x86/0xb8
? acpi_boot_init+0x494/0x4e3
? acpi_parse_x2apic+0x87/0x87
? setup_acpi_sci+0xa2/0xa2
? setup_arch+0x8db/0x9e1
? start_kernel+0x6a/0x547
? secondary_startup_64+0xb6/0xc0

Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot
services data to fix kexec breakage" is listed in Fixes: since it
introduces more occurrences where efi_memmap_insert() is invoked after
an efi_fake_mem= configuration has been parsed. Previously the side
effects of vestigial empty entries were benign, but with commit
af1648984828 that follow-on efi_memmap_insert() invocation triggers the
above crash signature.


Dan Williams (4):
efi: Add a flags parameter to efi_memory_map
efi: Add tracking for dynamically allocated memmaps
efi: Fix efi_memmap_alloc() leaks
efi: Fix handling of multiple efi_fake_mem= entries

arch/x86/platform/efi/efi.c | 2 +
arch/x86/platform/efi/quirks.c | 11 ++++---
drivers/firmware/efi/fake_mem.c | 37 +++++++++++++------------
drivers/firmware/efi/memmap.c | 58 ++++++++++++++++++++++++++++++---------
include/linux/efi.h | 13 +++++++--
5 files changed, 81 insertions(+), 40 deletions(-)

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