[PATCH 02/18] KVM: x86: hyper-v: Introduce helpers to check if VSM is exposed to guest

Nicolas Saenz Julienne
2024-06-09T15:51:35Z

Introduce a helper function to check if the guest exposes the VSM CPUID
bit.

Signed-off-by: Nicolas Saenz Julienne <nsaenz@amazon.com>
---
arch/x86/kvm/hyperv.h | 10 ++++++++++
include/asm-generic/hyperv-tlfs.h | 1 +
2 files changed, 11 insertions(+)

diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 923e64903da9a..d007d2203e0e4 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -265,6 +265,12 @@ static inline void kvm_hv_nested_transtion_tlb_flush(struct kvm_vcpu *vcpu,
}

int kvm_hv_vcpu_flush_tlb(struct kvm_vcpu *vcpu);
+static inline bool kvm_hv_cpuid_vsm_enabled(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
+
+ return hv_vcpu && (hv_vcpu->cpuid_cache.features_ebx & HV_ACCESS_VSM);
+}
#else /* CONFIG_KVM_HYPERV */
static inline void kvm_hv_setup_tsc_page(struct kvm *kvm,
struct pvclock_vcpu_time_info *hv_clock) {}
@@ -322,6 +328,10 @@ static inline u32 kvm_hv_get_vpindex(struct kvm_vcpu *vcpu)
return vcpu->vcpu_idx;
}
static inline void kvm_hv_nested_transtion_tlb_flush(struct kvm_vcpu *vcpu, bool tdp_enabled) {}
+static inline bool kvm_hv_cpuid_vsm_enabled(struct kvm_vcpu *vcpu)
+{
+ return false;
+}
#endif /* CONFIG_KVM_HYPERV */

#endif /* __ARCH_X86_KVM_HYPERV_H__ */
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 814207e7c37fc..ffac04bbd0c19 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -89,6 +89,7 @@
#define HV_ACCESS_STATS BIT(8)
#define HV_DEBUGGING BIT(11)
#define HV_CPU_MANAGEMENT BIT(12)
+#define HV_ACCESS_VSM BIT(16)
#define HV_ENABLE_EXTENDED_HYPERCALLS BIT(20)
#define HV_ISOLATION BIT(22)

--
2.40.1