[PATCH v8 3/8] KVM: x86: Add infrastructure for MSR filtering

[Alexander Graf <graf@amazon.com>]

In the following commits we will add pieces of MSR filtering.
To ensure that code compiles even with the feature half-merged, let's add
a few stubs and struct definitions before the real patches start.

Signed-off-by: Alexander Graf <graf@amazon.com>

---

v7 -> v8:

  s/KVM_MSR_ALLOW/KVM_MSR_FILTER/g
---
 arch/x86/include/asm/kvm_host.h | 1 +
 arch/x86/include/uapi/asm/kvm.h | 2 ++
 arch/x86/kvm/x86.c              | 6 ++++++
 arch/x86/kvm/x86.h              | 1 +
 4 files changed, 10 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 12c3f048f18b..9bc4fa34c90b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1230,6 +1230,7 @@ struct kvm_x86_ops {
 	int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
 
 	void (*migrate_timers)(struct kvm_vcpu *vcpu);
+	void (*msr_filter_changed)(struct kvm_vcpu *vcpu);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 0780f97c1850..c2fd0aa2f587 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -192,6 +192,8 @@ struct kvm_msr_list {
 	__u32 indices[0];
 };
 
+#define KVM_MSR_FILTER_READ  (1 << 0)
+#define KVM_MSR_FILTER_WRITE (1 << 1)
 
 struct kvm_cpuid_entry {
 	__u32 function;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5f0fbd49c65c..8fe7d9730182 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1487,6 +1487,12 @@ void kvm_enable_efer_bits(u64 mask)
 }
 EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);
 
+bool kvm_msr_allowed(struct kvm_vcpu *vcpu, u32 index, u32 type)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(kvm_msr_allowed);
+
 /*
  * Write @data into the MSR specified by @index.  Select MSR specific fault
  * checks are bypassed if @host_initiated is %true.
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 941f288c38aa..3900ab0c6004 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -374,6 +374,7 @@ bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu);
 int kvm_handle_memory_failure(struct kvm_vcpu *vcpu, int r,
 			      struct x86_exception *e);
 int kvm_handle_invpcid(struct kvm_vcpu *vcpu, unsigned long type, gva_t gva);
+bool kvm_msr_allowed(struct kvm_vcpu *vcpu, u32 index, u32 type);
 
 #define  KVM_MSR_RET_INVALID  2
 
-- 
2.28.0.394.ge197136389




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