KVM: selftests: Add helpers to get and modify a vCPU's CPUID entries

Add helpers to get a specific CPUID entry for a given vCPU, and to toggle
a specific CPUID-based feature for a vCPU.  The helpers will reduce the
amount of boilerplate code needed to tweak a vCPU's CPUID model, improve
code clarity, and most importantly move tests away from modifying the
static "cpuid" returned by kvm_get_supported_cpuid().

Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220614200707.3315957-23-seanjc@google.com

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index db8d8a84fbc31640fcfbedec9a689a5b2d3a928b..25b99eab7e7151bc66f1a483dfadb50e33d20c0f 100644 (file)
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -622,6 +622,19 @@ struct kvm_cpuid_entry2 *get_cpuid_entry(struct kvm_cpuid2 *cpuid,
                                         uint32_t function, uint32_t index);
 void vcpu_init_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid);
 
+static inline struct kvm_cpuid_entry2 *__vcpu_get_cpuid_entry(struct kvm_vcpu *vcpu,
+                                                             uint32_t function,
+                                                             uint32_t index)
+{
+       return get_cpuid_entry(vcpu->cpuid, function, index);
+}
+
+static inline struct kvm_cpuid_entry2 *vcpu_get_cpuid_entry(struct kvm_vcpu *vcpu,
+                                                           uint32_t function)
+{
+       return __vcpu_get_cpuid_entry(vcpu, function, 0);
+}
+
 static inline int __vcpu_set_cpuid(struct kvm_vcpu *vcpu)
 {
        int r;
@@ -645,6 +658,23 @@ static inline void vcpu_set_cpuid(struct kvm_vcpu *vcpu)
        vcpu_ioctl(vcpu, KVM_GET_CPUID2, vcpu->cpuid);
 }
 
+void vcpu_set_or_clear_cpuid_feature(struct kvm_vcpu *vcpu,
+                                    struct kvm_x86_cpu_feature feature,
+                                    bool set);
+
+static inline void vcpu_set_cpuid_feature(struct kvm_vcpu *vcpu,
+                                         struct kvm_x86_cpu_feature feature)
+{
+       vcpu_set_or_clear_cpuid_feature(vcpu, feature, true);
+
+}
+
+static inline void vcpu_clear_cpuid_feature(struct kvm_vcpu *vcpu,
+                                           struct kvm_x86_cpu_feature feature)
+{
+       vcpu_set_or_clear_cpuid_feature(vcpu, feature, false);
+}
+
 static inline struct kvm_cpuid_entry2 *kvm_get_supported_cpuid_index(uint32_t function,
                                                                     uint32_t index)
 {

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 5f359314a6ec8c0127b7cfe8bffc4a3b9e719df7..72aac618e0e4caa8e383e4e578f810d8147ec6dc 100644 (file)
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -766,6 +766,24 @@ void vcpu_init_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid)
        vcpu_set_cpuid(vcpu);
 }
 
+void vcpu_set_or_clear_cpuid_feature(struct kvm_vcpu *vcpu,
+                                    struct kvm_x86_cpu_feature feature,
+                                    bool set)
+{
+       struct kvm_cpuid_entry2 *entry;
+       u32 *reg;
+
+       entry = __vcpu_get_cpuid_entry(vcpu, feature.function, feature.index);
+       reg = (&entry->eax) + feature.reg;
+
+       if (set)
+               *reg |= BIT(feature.bit);
+       else
+               *reg &= ~BIT(feature.bit);
+
+       vcpu_set_cpuid(vcpu);
+}
+
 uint64_t vcpu_get_msr(struct kvm_vcpu *vcpu, uint64_t msr_index)
 {
        struct {