On Tue, Apr 25, 2017 at 09:14:01AM +0200, Thomas Huth wrote:
> On 05.04.2017 15:58, Thomas Huth wrote:
> > 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@xxxxxxxxxx>
> > ---
> > 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:
> >
>
> Ping!
>
> Paul, does this now look OK for you this way?
Yes, and I put it in, see commit feafd13c96d6.
Paul.
