From: Ashish Kalra <ashish.kalra@xxxxxxx>
For kexec use case, need to use and stick to the EFI memmap passed
from the first kernel via boot-params/setup data, hence,
skip efi_arch_mem_reserve() during kexec.
Additionally during SNP guest kexec testing discovered that EFI memmap
is corrupted during chained kexec. kexec_enter_virtual_mode() during
late init will remap the efi_memmap physical pages allocated in
efi_arch_mem_reserve() via memblock & then subsequently cause random
EFI memmap corruption once memblock is freed/teared-down.
Suggested-by: Dave Young <dyoung@xxxxxxxxxx>
[Dave Young: checking the md attribute instead of checking the efi_setup]
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
---
arch/x86/platform/efi/quirks.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index f0cc00032751..2b65b3863912 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -255,15 +255,32 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
struct efi_memory_map_data data = { 0 };
struct efi_mem_range mr;
efi_memory_desc_t md;
- int num_entries;
+ int num_entries, ret;
void *new;
- if (efi_mem_desc_lookup(addr, &md) ||
- md.type != EFI_BOOT_SERVICES_DATA) {
+ /*
+ * For kexec use case, we need to use the EFI memmap passed from the first
+ * kernel via setup data, so we need to skip this.
+ * Additionally kexec_enter_virtual_mode() during late init will remap
+ * the efi_memmap physical pages allocated here via memboot & then
+ * subsequently cause random EFI memmap corruption once memblock is freed.
+ */
+
+ ret = efi_mem_desc_lookup(addr, &md);
+ if (ret) {
pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr);
return;
}
+ if (md.type != EFI_BOOT_SERVICES_DATA) {
+ pr_err("Skip reserving non EFI Boot Service Data memory for %pa\n", &addr);
+ return;
+ }
+
+ /* Kexec copied the efi memmap from the first kernel, thus skip the case */
+ if (md.attribute & EFI_MEMORY_RUNTIME)
+ return;
+
if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) {
pr_err("Region spans EFI memory descriptors, %pa\n", &addr);
return;
--
2.34.1
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