From: Dave Young <dyoung@xxxxxxxxxx> [ 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 <dyoung@xxxxxxxxxx> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Acked-by: Matthew Garrett <mjg59@xxxxxxxxxx> Cc: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> Cc: Jerry Snitselaar <jsnitsel@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Lukas Wunner <lukas@xxxxxxxxx> Cc: Lyude Paul <lyude@xxxxxxxxxx> Cc: Octavian Purdila <octavian.purdila@xxxxxxxxx> Cc: Peter Jones <pjones@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Scott Talbert <swt@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-efi@xxxxxxxxxxxxxxx Cc: linux-integrity@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20191002165904.8819-8-ard.biesheuvel@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 a0e85f2aff7d8..b6669d326545a 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -896,9 +896,6 @@ static void __init kexec_enter_virtual_mode(void) if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX)) runtime_code_page_mkexec(); - - /* clean DUMMY object */ - efi_delete_dummy_variable(); #endif } -- 2.20.1
