KVM: PPC: Allow kvmppc_get_last_inst() to fail
On book3e, guest last instruction is read on the exit path using load
external pid (lwepx) dedicated instruction. This load operation may fail
due to TLB eviction and execute-but-not-read entries.
This patch lay down the path for an alternative solution to read the guest
last instruction, by allowing kvmppc_get_lat_inst() function to fail.
Architecture specific implmentations of kvmppc_load_last_inst() may read
last guest instruction and instruct the emulation layer to re-execute the
guest in case of failure.
Make kvmppc_get_last_inst() definition common between architectures.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index da86d9b..c5c64b6 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -224,19 +224,25 @@
* from opcode tables in the future. */
int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
- u32 inst = kvmppc_get_last_inst(vcpu);
- int ra = get_ra(inst);
- int rs = get_rs(inst);
- int rt = get_rt(inst);
- int sprn = get_sprn(inst);
- enum emulation_result emulated = EMULATE_DONE;
+ u32 inst;
+ int ra, rs, rt, sprn;
+ enum emulation_result emulated;
int advance = 1;
/* this default type might be overwritten by subcategories */
kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
+ emulated = kvmppc_get_last_inst(vcpu, false, &inst);
+ if (emulated != EMULATE_DONE)
+ return emulated;
+
pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
+ ra = get_ra(inst);
+ rs = get_rs(inst);
+ rt = get_rt(inst);
+ sprn = get_sprn(inst);
+
switch (get_op(inst)) {
case OP_TRAP:
#ifdef CONFIG_PPC_BOOK3S