Enable Direct TLB flush feature on nVMX when: - Enlightened VMCS is in use. - Direct TLB flush flag is enabled in eVMCS. - Direct TLB flush is enabled in partition assist page. Perform synthetic vmexit to L1 after processing TLB flush call upon request (HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH). Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> --- arch/x86/kvm/vmx/evmcs.c | 20 ++++++++++++++++++++ arch/x86/kvm/vmx/evmcs.h | 3 +++ arch/x86/kvm/vmx/nested.c | 16 ++++++++++++++++ 3 files changed, 39 insertions(+) diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c index 1705c4973636..cdf7ec5cb64c 100644 --- a/arch/x86/kvm/vmx/evmcs.c +++ b/arch/x86/kvm/vmx/evmcs.c @@ -6,6 +6,7 @@ #include "../hyperv.h" #include "../cpuid.h" #include "evmcs.h" +#include "nested.h" #include "vmcs.h" #include "vmx.h" #include "trace.h" @@ -438,6 +439,25 @@ int nested_enable_evmcs(struct kvm_vcpu *vcpu, return 0; } +bool nested_evmcs_direct_flush_enabled(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs; + struct hv_vp_assist_page assist_page; + + if (!evmcs) + return false; + + if (!evmcs->hv_enlightenments_control.nested_flush_hypercall) + return false; + + if (unlikely(!kvm_hv_get_assist_page(vcpu, &assist_page))) + return false; + + return assist_page.nested_control.features.directhypercall; +} + void vmx_post_hv_direct_flush(struct kvm_vcpu *vcpu) { + nested_vmx_vmexit(vcpu, HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH, 0, 0); } diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h index 8862692a4c5d..ab0949c22d2d 100644 --- a/arch/x86/kvm/vmx/evmcs.h +++ b/arch/x86/kvm/vmx/evmcs.h @@ -65,6 +65,8 @@ DECLARE_STATIC_KEY_FALSE(enable_evmcs); #define EVMCS1_UNSUPPORTED_VMENTRY_CTRL (VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL) #define EVMCS1_UNSUPPORTED_VMFUNC (VMX_VMFUNC_EPTP_SWITCHING) +#define HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH 0x10000031 + struct evmcs_field { u16 offset; u16 clean_field; @@ -244,6 +246,7 @@ int nested_enable_evmcs(struct kvm_vcpu *vcpu, uint16_t *vmcs_version); void nested_evmcs_filter_control_msr(u32 msr_index, u64 *pdata); int nested_evmcs_check_controls(struct vmcs12 *vmcs12); +bool nested_evmcs_direct_flush_enabled(struct kvm_vcpu *vcpu); void vmx_post_hv_direct_flush(struct kvm_vcpu *vcpu); #endif /* __KVM_X86_VMX_EVMCS_H */ diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 3121b761b1ee..efed9a199c84 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -1168,6 +1168,17 @@ static void nested_vmx_transition_tlb_flush(struct kvm_vcpu *vcpu, { struct vcpu_vmx *vmx = to_vmx(vcpu); + /* + * KVM_REQ_HV_TLB_FLUSH flushes entries from either L1's VPID or + * L2's VPID upon request from the guest. Make sure we check for + * pending entries for the case when the request got misplaced (e.g. + * a transition from L2->L1 happened while processing Direct TLB flush + * request or vice versa). kvm_hv_vcpu_flush_tlb() will not flush + * anything if there are no requests in the corresponding buffer. + */ + if (to_hv_vcpu(vcpu)) + kvm_make_request(KVM_REQ_HV_TLB_FLUSH, vcpu); + /* * If vmcs12 doesn't use VPID, L1 expects linear and combined mappings * for *all* contexts to be flushed on VM-Enter/VM-Exit, i.e. it's a @@ -5972,6 +5983,11 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, * Handle L2's bus locks in L0 directly. */ return true; + case EXIT_REASON_VMCALL: + /* Hyper-V Direct TLB flush hypercall is handled by L0 */ + return kvm_hv_direct_tlb_flush_exposed(vcpu) && + nested_evmcs_direct_flush_enabled(vcpu) && + kvm_hv_is_tlb_flush_hcall(vcpu); default: break; } -- 2.35.1