KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs
According to the PowerISA 2.07, mtspr and mfspr should not always
generate an illegal instruction exception when being used with an
undefined SPR, but rather treat the instruction as a NOP or inject a
privilege exception in some cases, too - depending on the SPR number.
Also turn the printk here into a ratelimited print statement, so that
the guest can not flood the dmesg log of the host by issueing lots of
illegal mtspr/mfspr instruction here.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 8359752..68d6898 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -503,10 +503,18 @@ int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
break;
unprivileged:
default:
- printk(KERN_INFO "KVM: invalid SPR write: %d\n", sprn);
-#ifndef DEBUG_SPR
- emulated = EMULATE_FAIL;
-#endif
+ pr_info_ratelimited("KVM: invalid SPR write: %d\n", sprn);
+ if (sprn & 0x10) {
+ if (kvmppc_get_msr(vcpu) & MSR_PR) {
+ kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV);
+ emulated = EMULATE_AGAIN;
+ }
+ } else {
+ if ((kvmppc_get_msr(vcpu) & MSR_PR) || sprn == 0) {
+ kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+ emulated = EMULATE_AGAIN;
+ }
+ }
break;
}
@@ -648,10 +656,20 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val
break;
default:
unprivileged:
- printk(KERN_INFO "KVM: invalid SPR read: %d\n", sprn);
-#ifndef DEBUG_SPR
- emulated = EMULATE_FAIL;
-#endif
+ pr_info_ratelimited("KVM: invalid SPR read: %d\n", sprn);
+ if (sprn & 0x10) {
+ if (kvmppc_get_msr(vcpu) & MSR_PR) {
+ kvmppc_core_queue_program(vcpu, SRR1_PROGPRIV);
+ emulated = EMULATE_AGAIN;
+ }
+ } else {
+ if ((kvmppc_get_msr(vcpu) & MSR_PR) || sprn == 0 ||
+ sprn == 4 || sprn == 5 || sprn == 6) {
+ kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+ emulated = EMULATE_AGAIN;
+ }
+ }
+
break;
}