[PATCH v9 18/40] KVM: x86: hyper-v: Introduce fast guest_hv_cpuid_has_l2_tlb_flush() check
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: 2022-08-03 13:46:49
Also in:
kvm, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), kvm x86 hyper-v (kvm/hyper-v), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Vitaly Kuznetsov, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Introduce a helper to quickly check if KVM needs to handle VMCALL/VMMCALL from L2 in L0 to process L2 TLB flush requests. Reviewed-by: Maxim Levitsky <redacted> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/hyperv.c | 6 ++++++ arch/x86/kvm/hyperv.h | 7 +++++++ 3 files changed, 14 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 75b95598b9fc..55845ece64f2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h@@ -641,6 +641,7 @@ struct kvm_vcpu_hv { u32 enlightenments_eax; /* HYPERV_CPUID_ENLIGHTMENT_INFO.EAX */ u32 enlightenments_ebx; /* HYPERV_CPUID_ENLIGHTMENT_INFO.EBX */ u32 syndbg_cap_eax; /* HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES.EAX */ + u32 nested_features_eax; /* HYPERV_CPUID_NESTED_FEATURES.EAX */ } cpuid_cache; struct kvm_vcpu_hv_tlb_flush_fifo tlb_flush_fifo[HV_NR_TLB_FLUSH_FIFOS];
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index be25a8ddab9d..42498a9132a5 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c@@ -2229,6 +2229,12 @@ void kvm_hv_set_cpuid(struct kvm_vcpu *vcpu) hv_vcpu->cpuid_cache.syndbg_cap_eax = entry->eax; else hv_vcpu->cpuid_cache.syndbg_cap_eax = 0; + + entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_NESTED_FEATURES); + if (entry) + hv_vcpu->cpuid_cache.nested_features_eax = entry->eax; + else + hv_vcpu->cpuid_cache.nested_features_eax = 0; } int kvm_hv_set_enforce_cpuid(struct kvm_vcpu *vcpu, bool enforce)
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 892c252b9bc3..0985c4beb69e 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h@@ -170,6 +170,13 @@ static inline void kvm_hv_vcpu_empty_flush_tlb(struct kvm_vcpu *vcpu) kfifo_reset_out(&tlb_flush_fifo->entries); } +static inline bool guest_hv_cpuid_has_l2_tlb_flush(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); + + return hv_vcpu && (hv_vcpu->cpuid_cache.nested_features_eax & HV_X64_NESTED_DIRECT_FLUSH); +} + static inline bool kvm_hv_is_tlb_flush_hcall(struct kvm_vcpu *vcpu) { struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
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2.35.3