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: Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>
Reviewed-by: Roman Kagan <rkagan@xxxxxxxxxxxxx>
Signed-off-by: Denis V. Lunev <den@xxxxxxxxxx>
CC: Gleb Natapov <gleb@xxxxxxxxxx>
CC: Paolo Bonzini <pbonzini@xxxxxxxxxx>
CC: Roman Kagan <rkagan@xxxxxxxxxxxxx>
CC: Denis V. Lunev <den@xxxxxxxxxx>
CC: qemu-devel@xxxxxxxxxx
---
Documentation/virtual/kvm/api.txt | 22 ++++++++++++++++++++++
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/hyperv.c | 20 ++++++++++++++++++++
arch/x86/kvm/x86.c | 6 ++++++
include/linux/kvm_host.h | 1 +
include/uapi/linux/kvm.h | 17 +++++++++++++++++
6 files changed, 67 insertions(+)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 16096a2..abc4f48 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -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];
};
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ad29e89..1cefa1e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -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 {
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 83a3c0c..41869a9 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -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;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 41f3030..04daf32 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6377,6 +6377,12 @@ 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;
+ }
}
/*
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a998e55..092bbd7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -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
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 27ce460..6e32f75 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -154,6 +154,20 @@ struct kvm_s390_skeys {
__u32 flags;
__u32 reserved[9];
};
+
+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;
+};
+
#define KVM_S390_GET_SKEYS_NONE 1
#define KVM_S390_SKEYS_MAX 1048576
@@ -184,6 +198,7 @@ struct kvm_s390_skeys {
#define KVM_EXIT_SYSTEM_EVENT 24
#define KVM_EXIT_S390_STSI 25
#define KVM_EXIT_IOAPIC_EOI 26
+#define KVM_EXIT_HYPERV 27
/* For KVM_EXIT_INTERNAL_ERROR */
/* Emulate instruction failed. */
@@ -338,6 +353,8 @@ struct kvm_run {
struct {
__u8 vector;
} eoi;
+ /* KVM_EXIT_HYPERV */
+ struct kvm_hyperv_exit hyperv;
/* Fix the size of the union. */
char padding[256];
};
--
2.4.3
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