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Subject[PATCH 7/7] efi/x86: do not clean dummy variable in kexec path
From: Dave Young <>

kexec reboot fails randomly in UEFI based kvm guest. The firmware
just reset while calling efi_delete_dummy_variable(); Unfortunately
I don't know how to debug the firmware, it is also possible a potential
problem on real hardware as well although nobody reproduced it.

The intention of efi_delete_dummy_variable is to trigger garbage collection
when entering virtual mode. But SetVirtualAddressMap can only run once
for each physical reboot, thus kexec_enter_virtual_mode is not necessarily
a good place to clean dummy object.

Drop efi_delete_dummy_variable so that kexec reboot can work.

Signed-off-by: Dave Young <>
Acked-by: Matthew Garrett <>
Signed-off-by: Ard Biesheuvel <>
arch/x86/platform/efi/efi.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index c202e1b07e29..425e025341db 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -917,9 +917,6 @@ static void __init kexec_enter_virtual_mode(void)

if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
- /* clean DUMMY object */
- efi_delete_dummy_variable();

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