diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2024-06-14 12:58:57 +0300 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-06-17 17:46:08 +0200 |
| commit | 06fa48d85b09b3e67afeda220bc19f7102b53beb (patch) | |
| tree | 4bf5652af251c807c0193f1176f02f96eae5a5fe | |
| parent | 859e63b789d6b17b3c64e51a0aabdc58752a0254 (diff) | |
x86/mm: Make e820__end_ram_pfn() cover E820_TYPE_ACPI ranges
e820__end_of_ram_pfn() is used to calculate max_pfn which, among other things,
guides where direct mapping ends. Any memory above max_pfn is not going to be
present in the direct mapping.
e820__end_of_ram_pfn() finds the end of the RAM based on the highest
E820_TYPE_RAM range. But it doesn't includes E820_TYPE_ACPI ranges into
calculation.
Despite the name, E820_TYPE_ACPI covers not only ACPI data, but also EFI tables
and might be required by kernel to function properly.
Usually the problem is hidden because there is some E820_TYPE_RAM memory above
E820_TYPE_ACPI. But crashkernel only presents pre-allocated crash memory as
E820_TYPE_RAM on boot. If the pre-allocated range is small, it can fit under the
last E820_TYPE_ACPI range.
Modify e820__end_of_ram_pfn() and e820__end_of_low_ram_pfn() to cover
E820_TYPE_ACPI memory.
The problem was discovered during debugging kexec for TDX guest. TDX guest uses
E820_TYPE_ACPI to store the unaccepted memory bitmap and pass it between the
kernels on kexec.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Tested-by: Tao Liu <ltao@redhat.com>
Link: https://lore.kernel.org/r/20240614095904.1345461-13-kirill.shutemov@linux.intel.com
| -rw-r--r-- | arch/x86/kernel/e820.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 68b09f718f10..4893d30ce438 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -828,7 +828,7 @@ u64 __init e820__memblock_alloc_reserved(u64 size, u64 align) /* * Find the highest page frame number we have available */ -static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type type) +static unsigned long __init e820__end_ram_pfn(unsigned long limit_pfn) { int i; unsigned long last_pfn = 0; @@ -839,7 +839,8 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type unsigned long start_pfn; unsigned long end_pfn; - if (entry->type != type) + if (entry->type != E820_TYPE_RAM && + entry->type != E820_TYPE_ACPI) continue; start_pfn = entry->addr >> PAGE_SHIFT; @@ -865,12 +866,12 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, enum e820_type unsigned long __init e820__end_of_ram_pfn(void) { - return e820_end_pfn(MAX_ARCH_PFN, E820_TYPE_RAM); + return e820__end_ram_pfn(MAX_ARCH_PFN); } unsigned long __init e820__end_of_low_ram_pfn(void) { - return e820_end_pfn(1UL << (32 - PAGE_SHIFT), E820_TYPE_RAM); + return e820__end_ram_pfn(1UL << (32 - PAGE_SHIFT)); } static void __init early_panic(char *msg) |