From 2ecb7402cfc7f22764e7bbc80790e66eadb20560 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Wed, 2 Oct 2019 18:59:04 +0200 Subject: [PATCH] efi/x86: Do not clean dummy variable in kexec path 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 Cc: linux-efi@vger.kernel.org Cc: linux-integrity@vger.kernel.org Link: https://lkml.kernel.org/r/20191002165904.8819-8-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- 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)) runtime_code_page_mkexec(); - - /* clean DUMMY object */ - efi_delete_dummy_variable(); #endif }