diff options
| author | Michael Ellerman | 2019-11-13 21:05:44 +1100 |
|---|---|---|
| committer | Michael Ellerman | 2019-11-14 15:37:59 +1100 |
| commit | af2e8c68b9c5403f77096969c516f742f5bb29e0 (patch) | |
| tree | 57edfd525c9dc14dac4921dff158a611be3f4a9f /arch/powerpc/include/asm | |
| parent | 39e72bf96f5847ba87cc5bd7a3ce0fed813dc9ad (diff) | |
KVM: PPC: Book3S HV: Flush link stack on guest exit to host kernel
On some systems that are vulnerable to Spectre v2, it is up to
software to flush the link stack (return address stack), in order to
protect against Spectre-RSB.
When exiting from a guest we do some house keeping and then
potentially exit to C code which is several stack frames deep in the
host kernel. We will then execute a series of returns without
preceeding calls, opening up the possiblity that the guest could have
poisoned the link stack, and direct speculative execution of the host
to a gadget of some sort.
To prevent this we add a flush of the link stack on exit from a guest.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm')
| -rw-r--r-- | arch/powerpc/include/asm/asm-prototypes.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h index 3ee92f692e64..d84d1417ddb6 100644 --- a/arch/powerpc/include/asm/asm-prototypes.h +++ b/arch/powerpc/include/asm/asm-prototypes.h @@ -153,9 +153,11 @@ void _kvmppc_save_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr); extern s32 patch__call_flush_count_cache; extern s32 patch__flush_count_cache_return; extern s32 patch__flush_link_stack_return; +extern s32 patch__call_kvm_flush_link_stack; extern s32 patch__memset_nocache, patch__memcpy_nocache; extern long flush_count_cache; +extern long kvm_flush_link_stack; #ifdef CONFIG_PPC_TRANSACTIONAL_MEM void kvmppc_save_tm_hv(struct kvm_vcpu *vcpu, u64 msr, bool preserve_nv); |