diff options
| author | Diana Craciun <diana.craciun@nxp.com> | 2018-12-12 15:03:03 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-12-20 12:59:03 +0100 |
| commit | 98518c4d8728656db349f875fcbbc7c126d4c973 (patch) | |
| tree | a0291c2161d8120adc257b786e2097160de54441 | |
| parent | powerpc/fsl: Fix spectre_v2 mitigations reporting (diff) | |
| download | linux-98518c4d8728656db349f875fcbbc7c126d4c973.tar.xz linux-98518c4d8728656db349f875fcbbc7c126d4c973.zip | |
powerpc/fsl: Emulate SPRN_BUCSR register
In order to flush the branch predictor the guest kernel performs
writes to the BUCSR register which is hypervisor privilleged. However,
the branch predictor is flushed at each KVM entry, so the branch
predictor has been already flushed, so just return as soon as possible
to guest.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
[mpe: Tweak comment formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| -rw-r--r-- | arch/powerpc/kvm/e500_emulate.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c index 3f8189eb56ed..fde1de08b4d7 100644 --- a/arch/powerpc/kvm/e500_emulate.c +++ b/arch/powerpc/kvm/e500_emulate.c @@ -277,6 +277,13 @@ int kvmppc_core_emulate_mtspr_e500(struct kvm_vcpu *vcpu, int sprn, ulong spr_va vcpu->arch.pwrmgtcr0 = spr_val; break; + case SPRN_BUCSR: + /* + * If we are here, it means that we have already flushed the + * branch predictor, so just return to guest. + */ + break; + /* extra exceptions */ #ifdef CONFIG_SPE_POSSIBLE case SPRN_IVOR32: |