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Subject[PATCH AUTOSEL 4.19 076/100] efi/x86: Do not clean dummy variable in kexec path
From: Dave Young <>

[ Upstream commit 2ecb7402cfc7f22764e7bbc80790e66eadb20560 ]

kexec reboot fails randomly in UEFI based KVM guest. The firmware
just resets 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 the 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 a dummy object.

Drop the efi_delete_dummy_variable so that kexec reboot can work.

Signed-off-by: Dave Young <>
Signed-off-by: Ard Biesheuvel <>
Acked-by: Matthew Garrett <>
Cc: Ben Dooks <>
Cc: Jarkko Sakkinen <>
Cc: Jerry Snitselaar <>
Cc: Linus Torvalds <>
Cc: Lukas Wunner <>
Cc: Lyude Paul <>
Cc: Octavian Purdila <>
Cc: Peter Jones <>
Cc: Peter Zijlstra <>
Cc: Scott Talbert <>
Cc: Thomas Gleixner <>
Signed-off-by: Ingo Molnar <>
Signed-off-by: Sasha Levin <>
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 9061babfbc83d..335a62e74a2e9 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -893,9 +893,6 @@ 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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