KVM: PPC: booke: category E.HV (GS-mode) support

Chips such as e500mc that implement category E.HV in Power ISA 2.06
provide hardware virtualization features, including a new MSR mode for
guest state.  The guest OS can perform many operations without trapping
into the hypervisor, including transitions to and from guest userspace.

Since we can use SRR1[GS] to reliably tell whether an exception came from
guest state, instead of messing around with IVPR, we use DO_KVM similarly
to book3s.

Current issues include:
 - Machine checks from guest state are not routed to the host handler.
 - The guest can cause a host oops by executing an emulated instruction
   in a page that lacks read permission.  Existing e500/4xx support has
   the same problem.

Includes work by Ashish Kalra <Ashish.Kalra@freescale.com>,
Varun Sethi <Varun.Sethi@freescale.com>, and
Liu Yu <yu.liu@freescale.com>.

Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: remove pt_regs usage]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 20 insertions, 3 deletions

diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 3e652da36534..904412bbea40 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -99,6 +99,12 @@ int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
         return emulated;
 }
 
+/*
+ * NOTE: some of these registers are not emulated on BOOKE_HV (GS-mode).
+ * Their backing store is in real registers, and these functions
+ * will return the wrong result if called for them in another context
+ * (such as debugging).
+ */
 int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
 {
         int emulated = EMULATE_DONE;
@@ -122,9 +128,11 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
                 kvmppc_set_tcr(vcpu, spr_val);
                 break;
 
-        /* Note: SPRG4-7 are user-readable. These values are
-         * loaded into the real SPRGs when resuming the
-         * guest. */
+        /*
+         * Note: SPRG4-7 are user-readable.
+         * These values are loaded into the real SPRGs when resuming the
+         * guest (PR-mode only).
+         */
         case SPRN_SPRG4:
                 vcpu->arch.shared->sprg4 = spr_val; break;
         case SPRN_SPRG5:
@@ -136,6 +144,9 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
 
         case SPRN_IVPR:
                 vcpu->arch.ivpr = spr_val;
+#ifdef CONFIG_KVM_BOOKE_HV
+                mtspr(SPRN_GIVPR, spr_val);
+#endif
                 break;
         case SPRN_IVOR0:
                 vcpu->arch.ivor[BOOKE_IRQPRIO_CRITICAL] = spr_val;
@@ -145,6 +156,9 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
                 break;
         case SPRN_IVOR2:
                 vcpu->arch.ivor[BOOKE_IRQPRIO_DATA_STORAGE] = spr_val;
+#ifdef CONFIG_KVM_BOOKE_HV
+                mtspr(SPRN_GIVOR2, spr_val);
+#endif
                 break;
         case SPRN_IVOR3:
                 vcpu->arch.ivor[BOOKE_IRQPRIO_INST_STORAGE] = spr_val;
@@ -163,6 +177,9 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
                 break;
         case SPRN_IVOR8:
                 vcpu->arch.ivor[BOOKE_IRQPRIO_SYSCALL] = spr_val;
+#ifdef CONFIG_KVM_BOOKE_HV
+                mtspr(SPRN_GIVOR8, spr_val);
+#endif
                 break;
         case SPRN_IVOR9:
                 vcpu->arch.ivor[BOOKE_IRQPRIO_AP_UNAVAIL] = spr_val;