KVM: PPC: Add sanity checking to vcpu_run

There are multiple features in PowerPC KVM that can now be enabled
depending on the user's wishes. Some of the combinations don't make
sense or don't work though.

So this patch adds a way to check if the executing environment would
actually be able to run the guest properly. It also adds sanity
checks if PVR is set (should always be true given the current code
flow), if PAPR is only used with book3s_64 where it works and that
HV KVM is only used in PAPR mode.

Signed-off-by: Alexander Graf <agraf@suse.de>

9 files changed, 67 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/kvm.h b/arch/powerpc/include/asm/kvm.h
index a6a253ee81bb..08fe69edcd10 100644
--- a/arch/powerpc/include/asm/kvm.h
+++ b/arch/powerpc/include/asm/kvm.h
@@ -284,6 +284,11 @@ struct kvm_guest_debug_arch {
 #define KVM_INTERRUPT_UNSET     -2U
 #define KVM_INTERRUPT_SET_LEVEL -3U
 
+#define KVM_CPU_440             1
+#define KVM_CPU_E500V2          2
+#define KVM_CPU_3S_32           3
+#define KVM_CPU_3S_64           4
+
 /* for KVM_CAP_SPAPR_TCE */
 struct kvm_create_spapr_tce {
         __u64 liobn;
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index e6813021126d..2b8284f4b4b7 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -390,6 +390,8 @@ struct kvm_vcpu_arch {
         u8 osi_needed;
         u8 osi_enabled;
         u8 papr_enabled;
+        u8 sane;
+        u8 cpu_type;
         u8 hcall_needed;
 
         u32 cpr0_cfgaddr; /* holds the last set cpr0_cfgaddr */
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index d121f49d62b8..46efd1a265c9 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -66,6 +66,7 @@ extern int kvmppc_emulate_instruction(struct kvm_run *run,
 extern int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu);
 extern void kvmppc_emulate_dec(struct kvm_vcpu *vcpu);
 extern u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb);
+extern int kvmppc_sanity_check(struct kvm_vcpu *vcpu);
 
 /* Core-specific hooks */
 
diff --git a/arch/powerpc/kvm/44x.c b/arch/powerpc/kvm/44x.c
index da3a1225c0ac..ca1f88b3dc59 100644
--- a/arch/powerpc/kvm/44x.c
+++ b/arch/powerpc/kvm/44x.c
@@ -78,6 +78,8 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu)
         for (i = 0; i < ARRAY_SIZE(vcpu_44x->shadow_refs); i++)
                 vcpu_44x->shadow_refs[i].gtlb_index = -1;
 
+        vcpu->arch.cpu_type = KVM_CPU_440;
+
         return 0;
 }
 
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index cc0d7f1b19ab..bf66ec731e8f 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -510,6 +510,9 @@ struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id)
         spin_unlock(&vcore->lock);
         vcpu->arch.vcore = vcore;
 
+        vcpu->arch.cpu_type = KVM_CPU_3S_64;
+        kvmppc_sanity_check(vcpu);
+
         return vcpu;
 
 free_vcpu:
@@ -800,6 +803,11 @@ int kvmppc_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu)
 {
         int r;
 
+        if (!vcpu->arch.sane) {
+                run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+                return -EINVAL;
+        }
+
         do {
                 r = kvmppc_run_vcpu(run, vcpu);
 
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 48558f6176e9..6e3488b09519 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -153,6 +153,7 @@ void kvmppc_set_pvr(struct kvm_vcpu *vcpu, u32 pvr)
                 if (!to_book3s(vcpu)->hior_sregs)
                         to_book3s(vcpu)->hior = 0xfff00000;
                 to_book3s(vcpu)->msr_mask = 0xffffffffffffffffULL;
+                vcpu->arch.cpu_type = KVM_CPU_3S_64;
         } else
 #endif
         {
@@ -160,8 +161,11 @@ void kvmppc_set_pvr(struct kvm_vcpu *vcpu, u32 pvr)
                 if (!to_book3s(vcpu)->hior_sregs)
                         to_book3s(vcpu)->hior = 0;
                 to_book3s(vcpu)->msr_mask = 0xffffffffULL;
+                vcpu->arch.cpu_type = KVM_CPU_3S_32;
         }
 
+        kvmppc_sanity_check(vcpu);
+
         /* If we are in hypervisor level on 970, we can tell the CPU to
          * treat DCBZ as 32 bytes store */
         vcpu->arch.hflags &= ~BOOK3S_HFLAG_DCBZ32;
@@ -938,6 +942,12 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 #endif
         ulong ext_msr;
 
+        /* Check if we can run the vcpu at all */
+        if (!vcpu->arch.sane) {
+                kvm_run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+                return -EINVAL;
+        }
+
         /* No need to go into the guest when all we do is going out */
         if (signal_pending(current)) {
                 kvm_run->exit_reason = KVM_EXIT_INTR;
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index ee45fa01220e..bb6c988f010a 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -316,6 +316,11 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 {
         int ret;
 
+        if (!vcpu->arch.sane) {
+                kvm_run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+                return -EINVAL;
+        }
+
         local_irq_disable();
         kvm_guest_enter();
         ret = __kvmppc_vcpu_run(kvm_run, vcpu);
@@ -618,6 +623,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
         int i;
+        int r;
 
         vcpu->arch.pc = 0;
         vcpu->arch.shared->msr = 0;
@@ -634,7 +640,9 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 
         kvmppc_init_timing_stats(vcpu);
 
-        return kvmppc_core_vcpu_setup(vcpu);
+        r = kvmppc_core_vcpu_setup(vcpu);
+        kvmppc_sanity_check(vcpu);
+        return r;
 }
 
 int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
diff --git a/arch/powerpc/kvm/e500.c b/arch/powerpc/kvm/e500.c
index 797a7447c268..26d20903f2bc 100644
--- a/arch/powerpc/kvm/e500.c
+++ b/arch/powerpc/kvm/e500.c
@@ -73,6 +73,8 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu)
         /* Since booke kvm only support one core, update all vcpus' PIR to 0 */
         vcpu->vcpu_id = 0;
 
+        vcpu->arch.cpu_type = KVM_CPU_E500V2;
+
         return 0;
 }
 
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 13bc798a4441..a8000ce562b0 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -95,6 +95,31 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
         return r;
 }
 
+int kvmppc_sanity_check(struct kvm_vcpu *vcpu)
+{
+        int r = false;
+
+        /* We have to know what CPU to virtualize */
+        if (!vcpu->arch.pvr)
+                goto out;
+
+        /* PAPR only works with book3s_64 */
+        if ((vcpu->arch.cpu_type != KVM_CPU_3S_64) && vcpu->arch.papr_enabled)
+                goto out;
+
+#ifdef CONFIG_KVM_BOOK3S_64_HV
+        /* HV KVM can only do PAPR mode for now */
+        if (!vcpu->arch.papr_enabled)
+                goto out;
+#endif
+
+        r = true;
+
+out:
+        vcpu->arch.sane = r;
+        return r ? 0 : -EINVAL;
+}
+
 int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu)
 {
         enum emulation_result er;
@@ -582,6 +607,9 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
                 break;
         }
 
+        if (!r)
+                r = kvmppc_sanity_check(vcpu);
+
         return r;
 }