Patch "x86/xen/efi: Initialize only the EFI struct members used by Xen" has been added to the 4.12-stable tree

Patch "x86/xen/efi: Initialize only the EFI struct members used by Xen" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    x86/xen/efi: Initialize only the EFI struct members used by Xen

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-xen-efi-initialize-only-the-efi-struct-members-used-by-xen.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6c64447ec58b0bac612732303f7ab04562124587 Mon Sep 17 00:00:00 2001
From: Daniel Kiper <daniel.kiper@oracle.com>
Date: Thu, 22 Jun 2017 12:51:37 +0200
Subject: x86/xen/efi: Initialize only the EFI struct members used by Xen

From: Daniel Kiper <daniel.kiper@oracle.com>

commit 6c64447ec58b0bac612732303f7ab04562124587 upstream.

The current approach, which is the wholesale efi struct initialization from
a 'efi_xen' local template is not robust. Usually if new member is defined
then it is properly initialized in drivers/firmware/efi/efi.c, but not in
arch/x86/xen/efi.c.

The effect is that the Xen initialization clears any fields the generic code
might have set and the Xen code does not know about yet.

I saw this happen a few times, so let's initialize only the EFI struct members
used by Xen and maintain no local duplicate, to avoid such issues in the future.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andrew.cooper3@citrix.com
Cc: jgross@suse.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1498128697-12943-3-git-send-email-daniel.kiper@oracle.com
[ Clarified the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/xen/efi.c |   45 ++++++++++++---------------------------------
 1 file changed, 12 insertions(+), 33 deletions(-)

--- a/arch/x86/xen/efi.c
+++ b/arch/x86/xen/efi.c
@@ -54,38 +54,6 @@ static efi_system_table_t efi_systab_xen
 	.tables		= EFI_INVALID_TABLE_ADDR  /* Initialized later. */
 };
 
-static const struct efi efi_xen __initconst = {
-	.systab                   = NULL, /* Initialized later. */
-	.runtime_version	  = 0,    /* Initialized later. */
-	.mps                      = EFI_INVALID_TABLE_ADDR,
-	.acpi                     = EFI_INVALID_TABLE_ADDR,
-	.acpi20                   = EFI_INVALID_TABLE_ADDR,
-	.smbios                   = EFI_INVALID_TABLE_ADDR,
-	.smbios3                  = EFI_INVALID_TABLE_ADDR,
-	.sal_systab               = EFI_INVALID_TABLE_ADDR,
-	.boot_info                = EFI_INVALID_TABLE_ADDR,
-	.hcdp                     = EFI_INVALID_TABLE_ADDR,
-	.uga                      = EFI_INVALID_TABLE_ADDR,
-	.uv_systab                = EFI_INVALID_TABLE_ADDR,
-	.fw_vendor                = EFI_INVALID_TABLE_ADDR,
-	.runtime                  = EFI_INVALID_TABLE_ADDR,
-	.config_table             = EFI_INVALID_TABLE_ADDR,
-	.get_time                 = xen_efi_get_time,
-	.set_time                 = xen_efi_set_time,
-	.get_wakeup_time          = xen_efi_get_wakeup_time,
-	.set_wakeup_time          = xen_efi_set_wakeup_time,
-	.get_variable             = xen_efi_get_variable,
-	.get_next_variable        = xen_efi_get_next_variable,
-	.set_variable             = xen_efi_set_variable,
-	.query_variable_info      = xen_efi_query_variable_info,
-	.update_capsule           = xen_efi_update_capsule,
-	.query_capsule_caps       = xen_efi_query_capsule_caps,
-	.get_next_high_mono_count = xen_efi_get_next_high_mono_count,
-	.reset_system             = xen_efi_reset_system,
-	.set_virtual_address_map  = NULL, /* Not used under Xen. */
-	.flags			  = 0     /* Initialized later. */
-};
-
 static efi_system_table_t __init *xen_efi_probe(void)
 {
 	struct xen_platform_op op = {
@@ -102,7 +70,18 @@ static efi_system_table_t __init *xen_ef
 
 	/* Here we know that Xen runs on EFI platform. */
 
-	efi = efi_xen;
+	efi.get_time                 = xen_efi_get_time;
+	efi.set_time                 = xen_efi_set_time;
+	efi.get_wakeup_time          = xen_efi_get_wakeup_time;
+	efi.set_wakeup_time          = xen_efi_set_wakeup_time;
+	efi.get_variable             = xen_efi_get_variable;
+	efi.get_next_variable        = xen_efi_get_next_variable;
+	efi.set_variable             = xen_efi_set_variable;
+	efi.query_variable_info      = xen_efi_query_variable_info;
+	efi.update_capsule           = xen_efi_update_capsule;
+	efi.query_capsule_caps       = xen_efi_query_capsule_caps;
+	efi.get_next_high_mono_count = xen_efi_get_next_high_mono_count;
+	efi.reset_system             = xen_efi_reset_system;
 
 	efi_systab_xen.tables = info->cfg.addr;
 	efi_systab_xen.nr_tables = info->cfg.nent;


Patches currently in stable-queue which might be from daniel.kiper@oracle.com are

queue-4.12/efi-process-the-memattr-table-only-if-efi_memmap-is-enabled.patch
queue-4.12/x86-xen-efi-initialize-only-the-efi-struct-members-used-by-xen.patch

Re: Patch "x86/xen/efi: Initialize only the EFI struct members used by Xen" has been added to the 4.12-stable tree

[Greg KH]

On Tue, Jul 18, 2017 at 05:16:30PM +0200, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     x86/xen/efi: Initialize only the EFI struct members used by Xen
> 
> to the 4.12-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      x86-xen-efi-initialize-only-the-efi-struct-members-used-by-xen.patch
> and it can be found in the queue-4.12 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.

Nope, now dropped it, it isn't stable kernel material.

thanks,

greg k-h