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Commit 87ee613d authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
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KVM: x86: hyperv: keep track of mismatched VP indexes 



In most common cases VP index of a vcpu matches its vcpu index. Userspace
is, however, free to set any mapping it wishes and we need to account for
that when we need to find a vCPU with a particular VP index. To keep search
algorithms optimal in both cases introduce 'num_mismatched_vp_indexes'
counter showing how many vCPUs with mismatching VP index we have. In case
the counter is zero we can assume vp_index == vcpu_idx.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: default avatarRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1779a39f

arch/x86/include/asm/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -790,6 +790,9 @@ struct kvm_hv { 
	u64 hv_reenlightenment_control;

	u64 hv_tsc_emulation_control;

	u64 hv_tsc_emulation_status;



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

	atomic_t num_mismatched_vp_indexes;

};



enum kvm_irqchip_mode {

arch/x86/kvm/hyperv.c

+23 −3
Original line number Diff line number Diff line
@@ -1045,11 +1045,31 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) 
	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;



	switch (msr) {

	case HV_X64_MSR_VP_INDEX:

		if (!host || (u32)data >= KVM_MAX_VCPUS)

	case HV_X64_MSR_VP_INDEX: {

		struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;

		int vcpu_idx = kvm_vcpu_get_idx(vcpu);

		u32 new_vp_index = (u32)data;



		if (!host || new_vp_index >= KVM_MAX_VCPUS)

			return 1;

		hv_vcpu->vp_index = (u32)data;



		if (new_vp_index == hv_vcpu->vp_index)

			return 0;



		/*

		 * The VP index is initialized to vcpu_index by

		 * kvm_hv_vcpu_postcreate so they initially match.  Now the

		 * VP index is changing, adjust num_mismatched_vp_indexes if

		 * it now matches or no longer matches vcpu_idx.

		 */

		if (hv_vcpu->vp_index == vcpu_idx)

			atomic_inc(&hv->num_mismatched_vp_indexes);

		else if (new_vp_index == vcpu_idx)

			atomic_dec(&hv->num_mismatched_vp_indexes);



		hv_vcpu->vp_index = new_vp_index;

		break;

	}

	case HV_X64_MSR_VP_ASSIST_PAGE: {

		u64 gfn;

		unsigned long addr;