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KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs

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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>
This commit is contained in:
Thomas Huth 2017-04-05 15:58:51 +02:00 committed by Paul Mackerras
parent 121f80ba68
commit feafd13c96
2 changed files with 34 additions and 8 deletions
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34
arch/powerpc/kvm/book3s_emulate.c
View file

@ -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;
}

8
arch/powerpc/kvm/emulate.c
View file

@ -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: