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

xen, x86/entry/64: Add xen NMI trap entry

to the 4.14-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: xen-x86-entry-64-add-xen-nmi-trap-entry.patch and it can be found in the queue-4.14 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 43e4111086a70c78bedb6ad990bee97f17b27a6e Mon Sep 17 00:00:00 2001

From: Juergen Gross jgross@suse.com Date: Thu, 2 Nov 2017 00:59:07 -0700 Subject: xen, x86/entry/64: Add xen NMI trap entry

From: Juergen Gross jgross@suse.com

commit 43e4111086a70c78bedb6ad990bee97f17b27a6e upstream.

Instead of trying to execute any NMI via the bare metal's NMI trap handler use a Xen specific one for PV domains, like we do for e.g. debug traps. As in a PV domain the NMI is handled via the normal kernel stack this is the correct thing to do.

This will enable us to get rid of the very fragile and questionable dependencies between the bare metal NMI handler and Xen assumptions believed to be broken anyway.

Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bpetkov@suse.de Cc: Brian Gerst brgerst@gmail.com Cc: Dave Hansen dave.hansen@intel.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/5baf5c0528d58402441550c5770b98e7961e7680.1509609304... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/entry/entry_64.S | 2 +- arch/x86/include/asm/traps.h | 2 +- arch/x86/xen/enlighten_pv.c | 2 +- arch/x86/xen/xen-asm_64.S | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1079,6 +1079,7 @@ idtentry int3 do_int3 has_error_code idtentry stack_segment do_stack_segment has_error_code=1

#ifdef CONFIG_XEN +idtentry xennmi do_nmi has_error_code=0 idtentry xendebug do_debug has_error_code=0 idtentry xenint3 do_int3 has_error_code=0 #endif @@ -1241,7 +1242,6 @@ ENTRY(error_exit) END(error_exit)

/* Runs on exception stack */ -/* XXX: broken on Xen PV */ ENTRY(nmi) UNWIND_HINT_IRET_REGS /* --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -38,9 +38,9 @@ asmlinkage void simd_coprocessor_error(v

#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV) asmlinkage void xen_divide_error(void); +asmlinkage void xen_xennmi(void); asmlinkage void xen_xendebug(void); asmlinkage void xen_xenint3(void); -asmlinkage void xen_nmi(void); asmlinkage void xen_overflow(void); asmlinkage void xen_bounds(void); asmlinkage void xen_invalid_op(void); --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -601,7 +601,7 @@ static struct trap_array_entry trap_arra #ifdef CONFIG_X86_MCE { machine_check, xen_machine_check, true }, #endif - { nmi, xen_nmi, true }, + { nmi, xen_xennmi, true }, { overflow, xen_overflow, false }, #ifdef CONFIG_IA32_EMULATION { entry_INT80_compat, xen_entry_INT80_compat, false }, --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S @@ -30,7 +30,7 @@ xen_pv_trap debug xen_pv_trap xendebug xen_pv_trap int3 xen_pv_trap xenint3 -xen_pv_trap nmi +xen_pv_trap xennmi xen_pv_trap overflow xen_pv_trap bounds xen_pv_trap invalid_op

Patches currently in stable-queue which might be from jgross@suse.com are

queue-4.14/x86-entry-64-move-the-ist-stacks-into-struct-cpu_entry_area.patch queue-4.14/x86-dumpstack-add-get_stack_info-support-for-the-sysenter-stack.patch queue-4.14/x86-virt-add-enum-for-hypervisors-to-replace-x86_hyper.patch queue-4.14/x86-xen-provide-pre-built-page-tables-only-for-config_xen_pv-y-and-config_xen_pvh-y.patch queue-4.14/x86-entry-remap-the-tss-into-the-cpu-entry-area.patch queue-4.14/x86-entry-64-paravirt-use-paravirt-safe-macro-to-access-eflags.patch queue-4.14/x86-mm-fixmap-generalize-the-gdt-fixmap-mechanism-introduce-struct-cpu_entry_area.patch queue-4.14/x86-xen-drop-5-level-paging-support-code-from-the-xen_pv-code.patch queue-4.14/x86-paravirt-dont-patch-flush_tlb_single.patch queue-4.14/x86-dumpstack-handle-stack-overflow-on-all-stacks.patch queue-4.14/x86-entry-64-return-to-userspace-from-the-trampoline-stack.patch queue-4.14/x86-paravirt-provide-a-way-to-check-for-hypervisors.patch queue-4.14/xen-x86-entry-64-add-xen-nmi-trap-entry.patch queue-4.14/x86-entry-64-create-a-per-cpu-syscall-entry-trampoline.patch queue-4.14/x86-xen-64-x86-entry-64-clean-up-sp-code-in-cpu_initialize_context.patch queue-4.14/x86-entry-64-de-xen-ify-our-nmi-code.patch queue-4.14/objtool-don-t-report-end-of-section-error-after-an-empty-unwind-hint.patch queue-4.14/x86-entry-64-use-a-per-cpu-trampoline-stack-for-idt-entries.patch queue-4.14/x86-cpufeatures-make-cpu-bugs-sticky.patch queue-4.14/x86-espfix-64-stop-assuming-that-pt_regs-is-on-the-entry-stack.patch queue-4.14/x86-xen-fix-xen-head-elf-annotations.patch queue-4.14/x86-entry-move-sysenter_stack-to-the-beginning-of-struct-tss_struct.patch queue-4.14/x86-entry-64-allocate-and-enable-the-sysenter-stack.patch queue-4.14/x86-unwinder-orc-dont-bail-on-stack-overflow.patch queue-4.14/x86-head-fix-head-elf-function-annotations.patch queue-4.14/x86-head-add-unwind-hint-annotations.patch queue-4.14/x86-head-remove-unused-bad_address-code.patch queue-4.14/x86-xen-add-unwind-hint-annotations.patch queue-4.14/x86-kasan-64-teach-kasan-about-the-cpu_entry_area.patch queue-4.14/x86-head-remove-confusing-comment.patch queue-4.14/x86-entry-64-remove-the-sysenter-stack-canary.patch queue-4.14/x86-entry-gdt-put-per-cpu-gdt-remaps-in-ascending-order.patch queue-4.14/x86-entry-fix-assumptions-that-the-hw-tss-is-at-the-beginning-of-cpu_tss.patch queue-4.14/x86-entry-64-make-cpu_entry_area.tss-read-only.patch queue-4.14/x86-virt-x86-platform-merge-struct-x86_hyper-into-struct-x86_platform-and-struct-x86_init.patch queue-4.14/x86-unwinder-handle-stack-overflows-more-gracefully.patch queue-4.14/x86-irq-64-print-the-offending-ip-in-the-stack-overflow-warning.patch queue-4.14/x86-entry-clean-up-the-sysenter_stack-code.patch queue-4.14/x86-entry-64-separate-cpu_current_top_of_stack-from-tss.sp0.patch queue-4.14/x86-boot-annotate-verify_cpu-as-a-callable-function.patch queue-4.14/x86-irq-remove-an-old-outdated-comment-about-context-tracking-races.patch