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 <th...@redhat.com>
---
v3:
- Make sure that we do not advance the program counter after we've
already changed it due to injecting a program interrupt
v2:
- Inject illegal instruction program interrupt instead of emulation
assist interrupt (according to the last programming note in section
6.5.9 of Book III of the PowerISA v2.07)
arch/powerpc/kvm/book3s_emulate.c | 34 ++++++++++++++++++++++++++--------
arch/powerpc/kvm/emulate.c | 8 ++++++++
2 files changed, 34 insertions(+), 8 deletions(-)
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;
}
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index b379146..c873ffe 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -259,10 +259,18 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
struct kvm_vcpu *vcpu)
case OP_31_XOP_MFSPR:
emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
+ if (emulated == EMULATE_AGAIN) {
+ emulated = EMULATE_DONE;
+ advance = 0;
+ }
break;
case OP_31_XOP_MTSPR:
emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
+ if (emulated == EMULATE_AGAIN) {
+ emulated = EMULATE_DONE;
+ advance = 0;
+ }
break;
case OP_31_XOP_TLBSYNC:
--
1.8.3.1
