@@ -97,4 +97,10 @@
#define RESUME_HOST RESUME_FLAG_HOST
#define RESUME_HOST_NV (RESUME_FLAG_HOST|RESUME_FLAG_NV)
+#define KVM_GUEST_MODE_NONE 0
+#define KVM_GUEST_MODE_GUEST 1
+#define KVM_GUEST_MODE_SKIP 2
+
+#define KVM_INST_FETCH_FAILED -1
+
#endif /* __POWERPC_KVM_ASM_H__ */
@@ -49,7 +49,7 @@ kvmppc_trampoline_\intno:
mfcr r12
stw r12, PACA_KVM_SCRATCH1(r13)
lbz r12, PACA_KVM_IN_GUEST(r13)
- cmpwi r12, 0
+ cmpwi r12, KVM_GUEST_MODE_NONE
bne ..kvmppc_handler_hasmagic_\intno
/* No KVM guest? Then jump back to the Linux handler! */
lwz r12, PACA_KVM_SCRATCH1(r13)
@@ -60,6 +60,11 @@ kvmppc_trampoline_\intno:
/* Now we know we're handling a KVM guest */
..kvmppc_handler_hasmagic_\intno:
+
+ /* Should we just skip the faulting instruction? */
+ cmpwi r12, KVM_GUEST_MODE_SKIP
+ beq kvmppc_handler_skip_ins
+
/* Let's store which interrupt we're handling */
li r12, \intno
@@ -86,6 +91,38 @@ INTERRUPT_TRAMPOLINE BOOK3S_INTERRUPT_ALTIVEC
INTERRUPT_TRAMPOLINE BOOK3S_INTERRUPT_VSX
/*
+ * Bring us back to the faulting code, but skip the
+ * faulting instruction.
+ *
+ * This is a generic exit path from the interrupt
+ * trampolines above.
+ *
+ * Input Registers:
+ *
+ * R12 = free
+ * R13 = PACA
+ * PACA.KVM.SCRATCH0 = guest R12
+ * PACA.KVM.SCRATCH1 = guest CR
+ * SPRG_SCRATCH0 = guest R13
+ *
+ */
+kvmppc_handler_skip_ins:
+
+ /* Patch the IP to the next instruction */
+ mfsrr0 r12
+ addi r12, r12, 4
+ mtsrr0 r12
+
+ /* Clean up all state */
+ lwz r12, PACA_KVM_SCRATCH1(r13)
+ mtcr r12
+ ld r12, PACA_KVM_SCRATCH0(r13)
+ mfspr r13, SPRN_SPRG_SCRATCH0
+
+ /* And get back into the code */
+ RFI
+
+/*
* This trampoline brings us back to a real mode handler
*
* Input Registers:
@@ -212,10 +212,6 @@ kvmppc_handler_trampoline_exit:
mfdar r5
mfdsisr r6
- /* Unset guest state */
- li r9, 0
- stb r9, PACA_KVM_IN_GUEST(r13)
-
/*
* In order for us to easily get the last instruction,
* we got the #vmexit at, we exploit the fact that the
@@ -233,18 +229,28 @@ kvmppc_handler_trampoline_exit:
ld_last_inst:
/* Save off the guest instruction we're at */
+
+ /* Set guest mode to 'jump over instruction' so if lwz faults
+ * we'll just continue at the next IP. */
+ li r9, KVM_GUEST_MODE_SKIP
+ stb r9, PACA_KVM_IN_GUEST(r13)
+
/* 1) enable paging for data */
mfmsr r9
ori r11, r9, MSR_DR /* Enable paging for data */
mtmsr r11
/* 2) fetch the instruction */
- /* XXX implement PACA_KVM_IN_GUEST=2 path to safely jump over this */
+ li r0, KVM_INST_FETCH_FAILED /* In case lwz faults */
lwz r0, 0(r3)
/* 3) disable paging again */
mtmsr r9
no_ld_last_inst:
+ /* Unset guest mode */
+ li r9, KVM_GUEST_MODE_NONE
+ stb r9, PACA_KVM_IN_GUEST(r13)
+
/* Restore bolted entries from the shadow and fix it along the way */
/* We don't store anything in entry 0, so we don't need to take care of it */
@@ -143,6 +143,10 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
pr_debug(KERN_INFO "Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
+ /* Try again next time */
+ if (inst == KVM_INST_FETCH_FAILED)
+ return EMULATE_DONE;
+
switch (get_op(inst)) {
case OP_TRAP:
#ifdef CONFIG_PPC64