* [PATCH v3] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs
@ 2017-04-05 13:58 Thomas Huth
2017-04-25 7:14 ` Thomas Huth
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Huth @ 2017-04-05 13:58 UTC (permalink / raw)
To: Paul Mackerras, kvm-ppc; +Cc: kvm, linuxppc-dev
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>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v3] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs
2017-04-05 13:58 [PATCH v3] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs Thomas Huth
@ 2017-04-25 7:14 ` Thomas Huth
2017-04-26 1:07 ` Paul Mackerras
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Huth @ 2017-04-25 7:14 UTC (permalink / raw)
To: Paul Mackerras, kvm-ppc; +Cc: kvm, linuxppc-dev
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@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:
>
Ping!
Paul, does this now look OK for you this way?
Thomas
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v3] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs
2017-04-25 7:14 ` Thomas Huth
@ 2017-04-26 1:07 ` Paul Mackerras
0 siblings, 0 replies; 3+ messages in thread
From: Paul Mackerras @ 2017-04-26 1:07 UTC (permalink / raw)
To: Thomas Huth; +Cc: kvm-ppc, kvm, linuxppc-dev
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@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:
> >
>
> Ping!
>
> Paul, does this now look OK for you this way?
Yes, and I put it in, see commit feafd13c96d6.
Paul.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-04-05 13:58 [PATCH v3] KVM: PPC: Book3S PR: Do not fail emulation with mtspr/mfspr for unknown SPRs Thomas Huth
2017-04-25 7:14 ` Thomas Huth
2017-04-26 1:07 ` Paul Mackerras
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