From: Dave Young <dyoung@redhat.com>
Date: Wed, 2 Oct 2019 18:59:04 +0200
Subject: efi/x86: Do not clean dummy variable in kexec path
Git-commit: 2ecb7402cfc7f22764e7bbc80790e66eadb20560
Patch-mainline: 5.4-rc3
References: bnc#1151927 5.3.9
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@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Matthew Garrett <mjg59@google.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Octavian Purdila <octavian.purdila@intel.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Talbert <swt@techie.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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
}
--
2.24.0