[PATCH 03/10] KVM: PPC: Check privilege level on SPRs
From: Alexander Graf <hidden>
Date: 2011-08-09 16:32:00
Also in:
kvm
Subsystem:
kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
We have 3 privilege levels: problem state, supervisor state and hypervisor state. Each of them can access different SPRs, so we need to check on every SPR if it's accessible in the respective mode. Signed-off-by: Alexander Graf <redacted> --- arch/powerpc/kvm/book3s_emulate.c | 25 +++++++++++++++++++++++++ 1 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 4668465..bf0ddcd 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c@@ -63,6 +63,25 @@ * function pointers, so let's just disable the define. */ #undef mfsrin +enum priv_level { + PRIV_PROBLEM = 0, + PRIV_SUPER = 1, + PRIV_HYPER = 2, +}; + +static bool spr_allowed(struct kvm_vcpu *vcpu, enum priv_level level) +{ + /* PAPR VMs only access supervisor SPRs */ + if (vcpu->arch.papr_enabled && (level > PRIV_SUPER)) + return false; + + /* Limit user space to its own small SPR set */ + if ((vcpu->arch.shared->msr & MSR_PR) && level > PRIV_PROBLEM) + return false; + + return true; +} + int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu, unsigned int inst, int *advance) {
@@ -296,6 +315,8 @@ int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs) switch (sprn) { case SPRN_SDR1: + if (!spr_allowed(vcpu, PRIV_HYPER)) + goto unprivileged; to_book3s(vcpu)->sdr1 = spr_val; break; case SPRN_DSISR:
@@ -390,6 +411,7 @@ int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs) case SPRN_PMC4_GEKKO: case SPRN_WPAR_GEKKO: break; +unprivileged: default: printk(KERN_INFO "KVM: invalid SPR write: %d\n", sprn); #ifndef DEBUG_SPR
@@ -421,6 +443,8 @@ int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt) break; } case SPRN_SDR1: + if (!spr_allowed(vcpu, PRIV_HYPER)) + goto unprivileged; kvmppc_set_gpr(vcpu, rt, to_book3s(vcpu)->sdr1); break; case SPRN_DSISR:
@@ -476,6 +500,7 @@ int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt) kvmppc_set_gpr(vcpu, rt, 0); break; default: +unprivileged: printk(KERN_INFO "KVM: invalid SPR read: %d\n", sprn); #ifndef DEBUG_SPR emulated = EMULATE_FAIL;
--
1.6.0.2