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a8b48a4dcc
This fixes a bug where the trap number that is returned by
__kvmppc_vcore_entry gets corrupted. The effect of the corruption
is that IPIs get ignored on POWER9 systems when the IPI is sent via
a doorbell interrupt to a CPU which is executing in a KVM guest.
The effect of the IPI being ignored is often that another CPU locks
up inside smp_call_function_many() (and if that CPU is holding a
spinlock, other CPUs then lock up inside raw_spin_lock()).
The trap number is currently held in register r12 for most of the
assembly-language part of the guest exit path. In that path, we
call kvmppc_subcore_exit_guest(), which is a C function, without
restoring r12 afterwards. Depending on the kernel config and the
compiler, it may modify r12 or it may not, so some config/compiler
combinations see the bug and others don't.
To fix this, we arrange for the trap number to be stored on the
stack from the 'guest_bypass:' label until the end of the function,
then the trap number is loaded and returned in r12 as before.
Cc: stable@vger.kernel.org # v4.8+
Fixes:
|
||
|---|---|---|
| .. | ||
| book3s_32_mmu_host.c | ||
| book3s_32_mmu.c | ||
| book3s_32_sr.S | ||
| book3s_64_mmu_host.c | ||
| book3s_64_mmu_hv.c | ||
| book3s_64_mmu_radix.c | ||
| book3s_64_mmu.c | ||
| book3s_64_slb.S | ||
| book3s_64_vio_hv.c | ||
| book3s_64_vio.c | ||
| book3s_emulate.c | ||
| book3s_exports.c | ||
| book3s_hv_builtin.c | ||
| book3s_hv_hmi.c | ||
| book3s_hv_interrupts.S | ||
| book3s_hv_ras.c | ||
| book3s_hv_rm_mmu.c | ||
| book3s_hv_rm_xics.c | ||
| book3s_hv_rm_xive.c | ||
| book3s_hv_rmhandlers.S | ||
| book3s_hv.c | ||
| book3s_interrupts.S | ||
| book3s_mmu_hpte.c | ||
| book3s_paired_singles.c | ||
| book3s_pr_papr.c | ||
| book3s_pr.c | ||
| book3s_rmhandlers.S | ||
| book3s_rtas.c | ||
| book3s_segment.S | ||
| book3s_xics.c | ||
| book3s_xics.h | ||
| book3s_xive_template.c | ||
| book3s_xive.c | ||
| book3s_xive.h | ||
| book3s.c | ||
| book3s.h | ||
| booke_emulate.c | ||
| booke_interrupts.S | ||
| booke.c | ||
| booke.h | ||
| bookehv_interrupts.S | ||
| e500_emulate.c | ||
| e500_mmu_host.c | ||
| e500_mmu_host.h | ||
| e500_mmu.c | ||
| e500.c | ||
| e500.h | ||
| e500mc.c | ||
| emulate_loadstore.c | ||
| emulate.c | ||
| fpu.S | ||
| irq.h | ||
| Kconfig | ||
| Makefile | ||
| mpic.c | ||
| powerpc.c | ||
| timing.c | ||
| timing.h | ||
| trace_book3s.h | ||
| trace_booke.h | ||
| trace_hv.h | ||
| trace_pr.h | ||
| trace.h | ||