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Commit 6f6a657c authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
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KVM/Hyper-V/VMX: Add direct tlb flush support 



Hyper-V provides direct tlb flush function which helps
L1 Hypervisor to handle Hyper-V tlb flush request from
L2 guest. Add the function support for VMX.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarTianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 344c6c80

arch/x86/include/asm/hyperv-tlfs.h

+4 −0
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ 
#define HV_X64_ENLIGHTENED_VMCS_RECOMMENDED		BIT(14)



/* Nested features. These are HYPERV_CPUID_NESTED_FEATURES.EAX bits. */

#define HV_X64_NESTED_DIRECT_FLUSH			BIT(17)

#define HV_X64_NESTED_GUEST_MAPPING_FLUSH		BIT(18)

#define HV_X64_NESTED_MSR_BITMAP			BIT(19)
@@ -892,4 +893,7 @@ struct hv_tlb_flush_ex { 
	u64 gva_list[];

} __packed;



struct hv_partition_assist_pg {

	u32 tlb_lock_count;

};

#endif

arch/x86/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -844,6 +844,8 @@ struct kvm_hv { 


	/* How many vCPUs have VP index != vCPU index */

	atomic_t num_mismatched_vp_indexes;



	struct hv_partition_assist_pg *hv_pa_pg;

};



enum kvm_irqchip_mode {

arch/x86/kvm/vmx/evmcs.h

+2 −0
Original line number Diff line number Diff line
@@ -178,6 +178,8 @@ static inline void evmcs_load(u64 phys_addr) 
	struct hv_vp_assist_page *vp_ap =

		hv_get_vp_assist_page(smp_processor_id());



	if (current_evmcs->hv_enlightenments_control.nested_flush_hypercall)

		vp_ap->nested_control.features.directhypercall = 1;

	vp_ap->current_nested_vmcs = phys_addr;

	vp_ap->enlighten_vmentry = 1;

}

arch/x86/kvm/vmx/vmx.c

+39 −0
Original line number Diff line number Diff line
@@ -486,6 +486,35 @@ static int hv_remote_flush_tlb(struct kvm *kvm) 
	return hv_remote_flush_tlb_with_range(kvm, NULL);

}



static int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu)

{

	struct hv_enlightened_vmcs *evmcs;

	struct hv_partition_assist_pg **p_hv_pa_pg =

			&vcpu->kvm->arch.hyperv.hv_pa_pg;

	/*

	 * Synthetic VM-Exit is not enabled in current code and so All

	 * evmcs in singe VM shares same assist page.

	 */

	if (!*p_hv_pa_pg) {

		*p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL);

		if (!*p_hv_pa_pg)

			return -ENOMEM;

		pr_debug("KVM: Hyper-V: allocated PA_PG for %llx\n",

		       (u64)&vcpu->kvm);

	}



	evmcs = (struct hv_enlightened_vmcs *)to_vmx(vcpu)->loaded_vmcs->vmcs;



	evmcs->partition_assist_page =

		__pa(*p_hv_pa_pg);

	evmcs->hv_vm_id = (u64)vcpu->kvm;

	evmcs->hv_enlightenments_control.nested_flush_hypercall = 1;



	pr_debug("KVM: Hyper-V: enabled DIRECT flush for %llx\n",

		 (u64)vcpu->kvm);

	return 0;

}



#endif /* IS_ENABLED(CONFIG_HYPERV) */



/*
@@ -6511,6 +6540,9 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) 
		current_evmcs->hv_clean_fields |=

			HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL;



	if (static_branch_unlikely(&enable_evmcs))

		current_evmcs->hv_vp_id = vcpu->arch.hyperv.vp_index;



	/* MSR_IA32_DEBUGCTLMSR is zeroed on vmexit. Restore it if needed */

	if (vmx->host_debugctlmsr)

		update_debugctlmsr(vmx->host_debugctlmsr);
@@ -6578,6 +6610,7 @@ static struct kvm *vmx_vm_alloc(void) 


static void vmx_vm_free(struct kvm *kvm)

{

	kfree(kvm->arch.hyperv.hv_pa_pg);

	vfree(to_kvm_vmx(kvm));

}
@@ -7837,6 +7870,7 @@ static void vmx_exit(void) 
			if (!vp_ap)

				continue;



			vp_ap->nested_control.features.directhypercall = 0;

			vp_ap->current_nested_vmcs = 0;

			vp_ap->enlighten_vmentry = 0;

		}
@@ -7876,6 +7910,11 @@ static int __init vmx_init(void) 
			pr_info("KVM: vmx: using Hyper-V Enlightened VMCS\n");

			static_branch_enable(&enable_evmcs);

		}



		if (ms_hyperv.nested_features & HV_X64_NESTED_DIRECT_FLUSH)

			vmx_x86_ops.enable_direct_tlbflush

				= hv_enable_direct_tlbflush;



	} else {

		enlightened_vmcs = false;

	}