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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-kernel@vger.kernel.org,
	Ben Dooks <ben.dooks@codethink.co.uk>,
	Dave Young <dyoung@redhat.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Jerry Snitselaar <jsnitsel@redhat.com>,
	linux-integrity@vger.kernel.org, Lukas Wunner <lukas@wunner.de>,
	Lyude Paul <lyude@redhat.com>, Matthew Garrett <mjg59@google.com>,
	Octavian Purdila <octavian.purdila@intel.com>,
	Peter Jones <pjones@redhat.com>, Scott Talbert <swt@techie.net>
Subject: [PATCH 7/7] efi/x86: do not clean dummy variable in kexec path
Date: Wed,  2 Oct 2019 18:59:04 +0200
Message-ID: <20191002165904.8819-8-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20191002165904.8819-1-ard.biesheuvel@linaro.org>

From: Dave Young <dyoung@redhat.com>

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 <dyoung@redhat.com>
Acked-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 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
 }
 
-- 
2.20.1


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-02 16:58 [GIT PULL 0/7] EFI fixes for v5.4 Ard Biesheuvel
2019-10-02 16:58 ` [PATCH 1/7] efi: cper: Fix endianness of PCIe class code Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/cper: " tip-bot2 for Lukas Wunner
2019-10-02 16:58 ` [PATCH 2/7] efivar/ssdt: don't iterate over EFI vars if no SSDT override was specified Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efivar/ssdt: Don't " tip-bot2 for Ard Biesheuvel
2019-10-02 16:59 ` [PATCH 3/7] efi/tpm: Don't access event->count when it isn't mapped Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] " tip-bot2 for Peter Jones
2019-10-02 16:59 ` [PATCH 4/7] efi/tpm: don't traverse an event log with no events Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/tpm: Don't " tip-bot2 for Peter Jones
2019-10-02 16:59 ` [PATCH 5/7] efi/tpm: only set efi_tpm_final_log_size after successful event log parsing Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi/tpm: Only set 'efi_tpm_final_log_size' " tip-bot2 for Jerry Snitselaar
2019-10-02 16:59 ` [PATCH 6/7] efi: make unexported efi_rci2_sysfs_init static Ard Biesheuvel
2019-10-07 14:49   ` [tip: efi/urgent] efi: Make unexported efi_rci2_sysfs_init() static tip-bot2 for Ben Dooks
2019-10-02 16:59 ` Ard Biesheuvel [this message]
2019-10-07 14:49   ` [tip: efi/urgent] efi/x86: Do not clean dummy variable in kexec path tip-bot2 for Dave Young

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