Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit db397571 authored by Andrey Smetanin's avatar Andrey Smetanin Committed by Paolo Bonzini
Browse files

kvm/x86: Hyper-V kvm exit 



A new vcpu exit is introduced to notify the userspace of the
changes in Hyper-V SynIC configuration triggered by guest writing to the
corresponding MSRs.

Changes v4:
* exit into userspace only if guest writes into SynIC MSR's

Changes v3:
* added KVM_EXIT_HYPERV types and structs notes into docs

Signed-off-by: default avatarAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: default avatarRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5c919412

Documentation/virtual/kvm/api.txt

+22 −0
Original line number Diff line number Diff line
@@ -3337,6 +3337,28 @@ the userspace IOAPIC should process the EOI and retrigger the interrupt if 
it is still asserted.  Vector is the LAPIC interrupt vector for which the

EOI was received.



		struct kvm_hyperv_exit {

#define KVM_EXIT_HYPERV_SYNIC          1

			__u32 type;

			union {

				struct {

					__u32 msr;

					__u64 control;

					__u64 evt_page;

					__u64 msg_page;

				} synic;

			} u;

		};

		/* KVM_EXIT_HYPERV */

                struct kvm_hyperv_exit hyperv;

Indicates that the VCPU exits into userspace to process some tasks

related to Hyper-V emulation.

Valid values for 'type' are:

	KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about

Hyper-V SynIC state change. Notification is used to remap SynIC

event/message pages and to enable/disable SynIC messages/events processing

in userspace.



		/* Fix the size of the union. */

		char padding[256];

	};

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -393,6 +393,7 @@ struct kvm_vcpu_hv { 
	u64 hv_vapic;

	s64 runtime_offset;

	struct kvm_vcpu_hv_synic synic;

	struct kvm_hyperv_exit exit;

};



struct kvm_vcpu_arch {

arch/x86/kvm/hyperv.c

+20 −0
Original line number Diff line number Diff line
@@ -130,6 +130,20 @@ static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint) 
	srcu_read_unlock(&kvm->irq_srcu, idx);

}



static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)

{

	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);

	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;



	hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNIC;

	hv_vcpu->exit.u.synic.msr = msr;

	hv_vcpu->exit.u.synic.control = synic->control;

	hv_vcpu->exit.u.synic.evt_page = synic->evt_page;

	hv_vcpu->exit.u.synic.msg_page = synic->msg_page;



	kvm_make_request(KVM_REQ_HV_EXIT, vcpu);

}



static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,

			 u32 msr, u64 data, bool host)

{
@@ -145,6 +159,8 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic, 
	switch (msr) {

	case HV_X64_MSR_SCONTROL:

		synic->control = data;

		if (!host)

			synic_exit(synic, msr);

		break;

	case HV_X64_MSR_SVERSION:

		if (!host) {
@@ -161,6 +177,8 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic, 
				break;

			}

		synic->evt_page = data;

		if (!host)

			synic_exit(synic, msr);

		break;

	case HV_X64_MSR_SIMP:

		if (data & HV_SYNIC_SIMP_ENABLE)
@@ -170,6 +188,8 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic, 
				break;

			}

		synic->msg_page = data;

		if (!host)

			synic_exit(synic, msr);

		break;

	case HV_X64_MSR_EOM: {

		int i;

arch/x86/kvm/x86.c

+6 −0
Original line number Diff line number Diff line
@@ -6482,6 +6482,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) 
			r = 0;

			goto out;

		}

		if (kvm_check_request(KVM_REQ_HV_EXIT, vcpu)) {

			vcpu->run->exit_reason = KVM_EXIT_HYPERV;

			vcpu->run->hyperv = vcpu->arch.hyperv.exit;

			r = 0;

			goto out;

		}

	}



	/*

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ static inline bool is_error_page(struct page *page) 
#define KVM_REQ_HV_CRASH          27

#define KVM_REQ_IOAPIC_EOI_EXIT   28

#define KVM_REQ_HV_RESET          29

#define KVM_REQ_HV_EXIT           30



#define KVM_USERSPACE_IRQ_SOURCE_ID		0

#define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID	1