Revert "KVM: Support vCPU-based gfn->hva cache"

This reverts commit bbd6411513aa8ef3ea02abab61318daf87c1af1e.

I've been sitting on this revert for too long and it unfortunately
missed 4.11.  It's also the reason why I haven't merged ring-based
dirty tracking for 4.12.

Using kvm_vcpu_memslots in kvm_gfn_to_hva_cache_init and
kvm_vcpu_write_guest_offset_cached means that the MSR value can
now be used to access SMRAM, simply by making it point to an SMRAM
physical address.  This is problematic because it lets the guest
OS overwrite memory that it shouldn't be able to touch.

Cc: stable@vger.kernel.org
Fixes: bbd6411513aa8ef3ea02abab61318daf87c1af1e
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 21 insertions, 20 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2fe9aa116288..b38a302858a0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1785,7 +1785,7 @@ static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
 	struct kvm_vcpu_arch *vcpu = &v->arch;
 	struct pvclock_vcpu_time_info guest_hv_clock;
 
-	if (unlikely(kvm_vcpu_read_guest_cached(v, &vcpu->pv_time,
+	if (unlikely(kvm_read_guest_cached(v->kvm, &vcpu->pv_time,
 		&guest_hv_clock, sizeof(guest_hv_clock))))
 		return;
 
@@ -1806,9 +1806,9 @@ static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
 	BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);
 
 	vcpu->hv_clock.version = guest_hv_clock.version + 1;
-	kvm_vcpu_write_guest_cached(v, &vcpu->pv_time,
-				    &vcpu->hv_clock,
-				    sizeof(vcpu->hv_clock.version));
+	kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
+				&vcpu->hv_clock,
+				sizeof(vcpu->hv_clock.version));
 
 	smp_wmb();
 
@@ -1822,16 +1822,16 @@ static void kvm_setup_pvclock_page(struct kvm_vcpu *v)
 
 	trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock);
 
-	kvm_vcpu_write_guest_cached(v, &vcpu->pv_time,
-				    &vcpu->hv_clock,
-				    sizeof(vcpu->hv_clock));
+	kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
+				&vcpu->hv_clock,
+				sizeof(vcpu->hv_clock));
 
 	smp_wmb();
 
 	vcpu->hv_clock.version++;
-	kvm_vcpu_write_guest_cached(v, &vcpu->pv_time,
-				    &vcpu->hv_clock,
-				    sizeof(vcpu->hv_clock.version));
+	kvm_write_guest_cached(v->kvm, &vcpu->pv_time,
+				&vcpu->hv_clock,
+				sizeof(vcpu->hv_clock.version));
 }
 
 static int kvm_guest_time_update(struct kvm_vcpu *v)
@@ -2064,7 +2064,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
 		return 0;
 	}
 
-	if (kvm_vcpu_gfn_to_hva_cache_init(vcpu, &vcpu->arch.apf.data, gpa,
+	if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa,
 					sizeof(u32)))
 		return 1;
 
@@ -2083,7 +2083,7 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
 	if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
 		return;
 
-	if (unlikely(kvm_vcpu_read_guest_cached(vcpu, &vcpu->arch.st.stime,
+	if (unlikely(kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
 		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
 		return;
 
@@ -2094,7 +2094,7 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
 
 	vcpu->arch.st.steal.version += 1;
 
-	kvm_vcpu_write_guest_cached(vcpu, &vcpu->arch.st.stime,
+	kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
 		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time));
 
 	smp_wmb();
@@ -2103,14 +2103,14 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
 		vcpu->arch.st.last_steal;
 	vcpu->arch.st.last_steal = current->sched_info.run_delay;
 
-	kvm_vcpu_write_guest_cached(vcpu, &vcpu->arch.st.stime,
+	kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
 		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time));
 
 	smp_wmb();
 
 	vcpu->arch.st.steal.version += 1;
 
-	kvm_vcpu_write_guest_cached(vcpu, &vcpu->arch.st.stime,
+	kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
 		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time));
 }
 
@@ -2215,7 +2215,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (!(data & 1))
 			break;
 
-		if (kvm_vcpu_gfn_to_hva_cache_init(vcpu,
+		if (kvm_gfn_to_hva_cache_init(vcpu->kvm,
 		     &vcpu->arch.pv_time, data & ~1ULL,
 		     sizeof(struct pvclock_vcpu_time_info)))
 			vcpu->arch.pv_time_enabled = false;
@@ -2236,7 +2236,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (data & KVM_STEAL_RESERVED_MASK)
 			return 1;
 
-		if (kvm_vcpu_gfn_to_hva_cache_init(vcpu, &vcpu->arch.st.stime,
+		if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.st.stime,
 						data & KVM_STEAL_VALID_BITS,
 						sizeof(struct kvm_steal_time)))
 			return 1;
@@ -2858,7 +2858,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
 
 	vcpu->arch.st.steal.preempted = 1;
 
-	kvm_vcpu_write_guest_offset_cached(vcpu, &vcpu->arch.st.stime,
+	kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,
 			&vcpu->arch.st.steal.preempted,
 			offsetof(struct kvm_steal_time, preempted),
 			sizeof(vcpu->arch.st.steal.preempted));
@@ -8527,8 +8527,9 @@ static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
 
 static int apf_put_user(struct kvm_vcpu *vcpu, u32 val)
 {
-	return kvm_vcpu_write_guest_cached(vcpu, &vcpu->arch.apf.data, &val,
-					   sizeof(val));
+
+	return kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.apf.data, &val,
+				      sizeof(val));
 }
 
 void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,