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

x86/kaiser: Move feature detection up

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-kaiser-move-feature-detection-up.patch and it can be found in the queue-4.4 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 foo@baz Wed Jan 3 18:58:12 CET 2018

From: Borislav Petkov bp@suse.de Date: Mon, 25 Dec 2017 13:57:16 +0100 Subject: x86/kaiser: Move feature detection up

From: Borislav Petkov bp@suse.de

... before the first use of kaiser_enabled as otherwise funky things happen:

about to get started... (XEN) d0v0 Unhandled page fault fault/trap [#14, ec=0000] (XEN) Pagetable walk from ffff88022a449090: (XEN) L4[0x110] = 0000000229e0e067 0000000000001e0e (XEN) L3[0x008] = 0000000000000000 ffffffffffffffff (XEN) domain_crash_sync called from entry.S: fault at ffff82d08033fd08 entry.o#create_bounce_frame+0x135/0x14d (XEN) Domain 0 (vcpu#0) crashed on cpu#0: (XEN) ----[ Xen-4.9.1_02-3.21 x86_64 debug=n Not tainted ]---- (XEN) CPU: 0 (XEN) RIP: e033:[<ffffffff81007460>] (XEN) RFLAGS: 0000000000000286 EM: 1 CONTEXT: pv guest (d0v0)

Signed-off-by: Borislav Petkov bp@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/kaiser.h | 2 ++ arch/x86/kernel/setup.c | 7 +++++++ arch/x86/mm/kaiser.c | 2 -- 3 files changed, 9 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/kaiser.h +++ b/arch/x86/include/asm/kaiser.h @@ -96,8 +96,10 @@ DECLARE_PER_CPU(unsigned long, x86_cr3_p extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];

extern int kaiser_enabled; +extern void __init kaiser_check_boottime_disable(void); #else #define kaiser_enabled 0 +static inline void __init kaiser_check_boottime_disable(void) {} #endif /* CONFIG_KAISER */

/* --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -112,6 +112,7 @@ #include <asm/alternative.h> #include <asm/prom.h> #include <asm/microcode.h> +#include <asm/kaiser.h>

/* * max_low_pfn_mapped: highest direct mapped pfn under 4GB @@ -1016,6 +1017,12 @@ void __init setup_arch(char **cmdline_p) */ init_hypervisor_platform();

+ /* + * This needs to happen right after XENPV is set on xen and + * kaiser_enabled is checked below in cleanup_highmap(). + */ + kaiser_check_boottime_disable(); + x86_init.resources.probe_roms();

/* after parse_early_param, so could debug it */ --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -311,8 +311,6 @@ void __init kaiser_init(void) { int cpu;

- kaiser_check_boottime_disable(); - if (!kaiser_enabled) return;

Patches currently in stable-queue which might be from bp@suse.de are

queue-4.4/x86-paravirt-dont-patch-flush_tlb_single.patch queue-4.4/x86-kaiser-reenable-paravirt.patch queue-4.4/x86-kaiser-rename-and-simplify-x86_feature_kaiser-handling.patch queue-4.4/x86-kaiser-check-boottime-cmdline-params.patch queue-4.4/x86-kaiser-move-feature-detection-up.patch