From 47b64e9de8bba4e6ccd0976bce6cf99446daf82e Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Thu, 2 Nov 2017 00:59:07 -0700 Subject: [PATCH 095/242] xen, x86/entry/64: Add xen NMI trap entry MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit CVE-2017-5754 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 Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/5baf5c0528d58402441550c5770b98e7961e7680.1509609304.git.luto@kernel.org Signed-off-by: Ingo Molnar (cherry picked from commit 43e4111086a70c78bedb6ad990bee97f17b27a6e) Signed-off-by: Andy Whitcroft Signed-off-by: Kleber Sacilotto de Souza (cherry picked from commit 20c970e03b42141abf6c45938ce6d4fdc3555921) Signed-off-by: Fabian Grünbichler --- arch/x86/include/asm/traps.h | 2 +- arch/x86/xen/enlighten_pv.c | 2 +- arch/x86/entry/entry_64.S | 2 +- arch/x86/xen/xen-asm_64.S | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 8e5bf86f87e5..b052a7621ca1 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -55,9 +55,9 @@ asmlinkage void simd_coprocessor_error(void); #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); diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 69b9deff7e5c..8da4eff19c2a 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -600,7 +600,7 @@ static struct trap_array_entry trap_array[] = { #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 }, diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 4eff3aca54ed..5a6aba7cf3bd 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1091,6 +1091,7 @@ idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK 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 @@ -1253,7 +1254,6 @@ ENTRY(error_exit) END(error_exit) /* Runs on exception stack */ -/* XXX: broken on Xen PV */ ENTRY(nmi) UNWIND_HINT_IRET_REGS /* diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S index dae2cc33afb5..286ecc198562 100644 --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S @@ -29,7 +29,7 @@ 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 -- 2.14.2