linux/arch/x86/kvm
Josh Poimboeuf 3d9606b0e0 x86/kvm: Fix "missing ENDBR" BUG for fastop functions
The following BUG was reported:

  traps: Missing ENDBR: andw_ax_dx+0x0/0x10 [kvm]
  ------------[ cut here ]------------
  kernel BUG at arch/x86/kernel/traps.c:253!
  invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
   <TASK>
   asm_exc_control_protection+0x2b/0x30
  RIP: 0010:andw_ax_dx+0x0/0x10 [kvm]
  Code: c3 cc cc cc cc 0f 1f 44 00 00 66 0f 1f 00 48 19 d0 c3 cc cc cc
        cc 0f 1f 40 00 f3 0f 1e fa 20 d0 c3 cc cc cc cc 0f 1f 44 00 00
        <66> 0f 1f 00 66 21 d0 c3 cc cc cc cc 0f 1f 40 00 66 0f 1f 00 21
        d0

   ? andb_al_dl+0x10/0x10 [kvm]
   ? fastop+0x5d/0xa0 [kvm]
   x86_emulate_insn+0x822/0x1060 [kvm]
   x86_emulate_instruction+0x46f/0x750 [kvm]
   complete_emulated_mmio+0x216/0x2c0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x604/0x650 [kvm]
   kvm_vcpu_ioctl+0x2f4/0x6b0 [kvm]
   ? wake_up_q+0xa0/0xa0

The BUG occurred because the ENDBR in the andw_ax_dx() fastop function
had been incorrectly "sealed" (converted to a NOP) by apply_ibt_endbr().

Objtool marked it to be sealed because KVM has no compile-time
references to the function.  Instead KVM calculates its address at
runtime.

Prevent objtool from annotating fastop functions as sealable by creating
throwaway dummy compile-time references to the functions.

Fixes: 6649fa876d ("x86/ibt,kvm: Add ENDBR to fastops")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Debugged-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Message-Id: <0d4116f90e9d0c1b754bb90c585e6f0415a1c508.1660837839.git.jpoimboe@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19 04:05:42 -04:00
..
mmu KVM: Rename mmu_notifier_* to mmu_invalidate_* 2022-08-19 04:05:41 -04:00
svm KVM: SVM: Disable SEV-ES support if MMIO caching is disable 2022-08-10 15:08:25 -04:00
vmx * Xen timer fixes 2022-08-11 12:10:08 -07:00
cpuid.c KVM: x86: Add dedicated helper to get CPUID entry with significant index 2022-07-14 11:38:32 -04:00
cpuid.h KVM: x86: Add dedicated helper to get CPUID entry with significant index 2022-07-14 11:38:32 -04:00
debugfs.c KVM: x86: Introduce "struct kvm_caps" to track misc caps/settings 2022-06-08 05:21:16 -04:00
emulate.c x86/kvm: Fix "missing ENDBR" BUG for fastop functions 2022-08-19 04:05:42 -04:00
fpu.h
hyperv.c KVM: x86: Add dedicated helper to get CPUID entry with significant index 2022-07-14 11:38:32 -04:00
hyperv.h KVM: x86: hyper-v: Avoid writing to TSC page without an active vCPU 2022-04-11 13:29:51 -04:00
i8254.c KVM: x86: PIT: Preserve state of speaker port data bit 2022-06-08 13:06:20 -04:00
i8254.h KVM: x86: PIT: Preserve state of speaker port data bit 2022-06-08 13:06:20 -04:00
i8259.c KVM: x86/i8259: Remove a dead store of irq in a conditional block 2022-04-02 05:41:19 -04:00
ioapic.c KVM: x86/ioapic: Remove unused "addr" and "length" of ioapic_read_indirect() 2022-02-10 13:47:13 -05:00
ioapic.h x86/kvm: remove unused ack_notifier callbacks 2021-11-18 07:05:57 -05:00
irq_comm.c KVM: x86/xen: Make kvm_xen_set_evtchn() reusable from other places 2022-04-02 05:41:14 -04:00
irq.c KVM: x86/xen: handle PV timers oneshot mode 2022-04-02 05:41:16 -04:00
irq.h x86/kvm: remove unused ack_notifier callbacks 2021-11-18 07:05:57 -05:00
Kconfig KVM: x86/mmu: Remove MMU auditing 2022-02-18 13:46:23 -05:00
kvm_cache_regs.h KVM: X86: Remove kvm_register_clear_available() 2021-12-08 04:25:03 -05:00
kvm_emulate.h KVM: x86: Bug the VM if the emulator accesses a non-existent GPR 2022-06-10 10:01:33 -04:00
kvm_onhyperv.c KVM: x86: Uninline and export hv_track_root_tdp() 2022-02-10 13:47:19 -05:00
kvm_onhyperv.h KVM: x86: Uninline and export hv_track_root_tdp() 2022-02-10 13:47:19 -05:00
lapic.c KVM: x86: Bug the VM if an accelerated x2APIC trap occurs on a "bad" reg 2022-08-10 15:08:23 -04:00
lapic.h KVM: x86: Fix handling of APIC LVT updates when userspace changes MCG_CAP 2022-07-08 15:58:16 -07:00
Makefile KVM: Add Makefile.kvm for common files, use it for x86 2021-12-09 12:56:02 -05:00
mmu.h KVM: SVM: Disable SEV-ES support if MMIO caching is disable 2022-08-10 15:08:25 -04:00
mtrr.c
pmu.c Revert "KVM: x86: always allow host-initiated writes to PMU MSRs" 2022-06-20 11:49:46 -04:00
pmu.h Revert "KVM: x86: always allow host-initiated writes to PMU MSRs" 2022-06-20 11:49:46 -04:00
reverse_cpuid.h
trace.h KVM: x86: move all vcpu->arch.pio* setup in emulator_pio_in_out() 2022-06-24 12:53:50 -04:00
tss.h
x86.c * Xen timer fixes 2022-08-11 12:10:08 -07:00
x86.h KVM: x86: Split kvm_is_valid_cr4() and export only the non-vendor bits 2022-07-28 13:22:25 -04:00
xen.c KVM: x86/xen: Stop Xen timer before changing IRQ 2022-08-10 15:08:25 -04:00
xen.h KVM: x86: do not set st->preempted when going back to user space 2022-06-08 04:21:06 -04:00