[Qemu-devel] [PATCH 0/2] Hyper-V synthetic interrupt controller

[Qemu-devel] [PATCH 0/2] Hyper-V synthetic interrupt controller

[Denis V. Lunev]

This patchset implements the KVM part of the synthetic interrupt
controller (synic) which is a building block of the Hyper-V
paravirtualized device bus (vmbus).

Synic is a lapic extension, which is controlled via MSRs and maintains
for each vCPU
 - 16 synthetic interrupt "lines" (SINT's); each can be configured to
   trigger a specific interrupt vector optionally with auto-EOI
   semantics
 - a message page in the guest memory with 16 256-byte per-SINT message
   slots
 - an event flag page in the guest memory with 16 2048-bit per-SINT
   event flag areas

The host triggers a SINT whenever it delivers a new message to the
corresponding slot or flips an event flag bit in the corresponding area.
The guest informs the host that it can try delivering a message by
explicitly asserting EOI in lapic or writing to End-Of-Message (EOM)
MSR.

The userspace (qemu) triggers interrupts and receives EOM notifications
via irqfd with resampler; for that, a GSI is allocated for each
configured SINT, and irq_routing api is extended to support GSI-SINT
mapping.

Besides, a new vcpu exit is introduced to notify the userspace of the
changes in synic configuraion triggered by guest writing to the
corresponding MSRs.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>

[Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Denis V. Lunev]

From: Andrey Smetanin <asmetanin@virtuozzo.com>

Synic is a lapic extension, which is controlled via MSRs and maintains
for each vCPU
 - 16 synthetic interrupt "lines" (SINT's); each can be configured to
   trigger a specific interrupt vector optionally with auto-EOI
   semantics
 - a message page in the guest memory with 16 256-byte per-SINT message
   slots
 - an event flag page in the guest memory with 16 2048-bit per-SINT
   event flag areas

The host triggers a SINT whenever it delivers a new message to the
corresponding slot or flips an event flag bit in the corresponding area.
The guest informs the host that it can try delivering a message by
explicitly asserting EOI in lapic or writing to End-Of-Message (EOM)
MSR.

The userspace (qemu) triggers interrupts and receives EOM notifications
via irqfd with resampler; for that, a GSI is allocated for each
configured SINT, and irq_routing api is extended to support GSI-SINT
mapping.

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/powerpc/kvm/mpic.c         |  18 +++
 arch/s390/kvm/interrupt.c       |  18 +++
 arch/x86/include/asm/kvm_host.h |  14 +++
 arch/x86/kvm/hyperv.c           | 266 ++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/hyperv.h           |  20 +++
 arch/x86/kvm/irq_comm.c         |  16 +++
 arch/x86/kvm/lapic.c            |  15 ++-
 arch/x86/kvm/lapic.h            |   5 +
 arch/x86/kvm/x86.c              |   4 +
 drivers/hv/hyperv_vmbus.h       |   5 -
 include/linux/kvm_host.h        |  12 ++
 include/uapi/linux/hyperv.h     |  12 ++
 include/uapi/linux/kvm.h        |   8 ++
 virt/kvm/arm/vgic.c             |  18 +++
 virt/kvm/eventfd.c              |  35 +++++-
 virt/kvm/irqchip.c              |  24 +++-
 16 files changed, 475 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/kvm/mpic.c b/arch/powerpc/kvm/mpic.c
index 6249cdc..01e7fb4 100644
--- a/arch/powerpc/kvm/mpic.c
+++ b/arch/powerpc/kvm/mpic.c
@@ -1850,3 +1850,21 @@ int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
 out:
 	return r;
 }
+
+/* Hyper-V Synic not implemented */
+int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
+		    struct kvm *kvm, int irq_source_id, int level,
+		    bool line_status)
+{
+	return -ENOTSUP;
+}
+
+int kvm_hv_get_sint_gsi(struct kvm_vcpu *vcpu, u32 sint)
+{
+	return -ENOTSUP;
+}
+
+int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vcpu_id, u32 sint, int gsi)
+{
+	return -ENOTSUP;
+}
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 5c2c169..7fa8d9d 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2285,3 +2285,21 @@ int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len)
 
 	return n;
 }
+
+/* Hyper-V Synic not implemented */
+int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
+		    struct kvm *kvm, int irq_source_id, int level,
+		    bool line_status)
+{
+	return -ENOTSUP;
+}
+
+int kvm_hv_get_sint_gsi(struct kvm_vcpu *vcpu, u32 sint)
+{
+	return -ENOTSUP;
+}
+
+int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vcpu_id, u32 sint, int gsi)
+{
+	return -ENOTSUP;
+}
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cdbdb55..e614a543 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -25,6 +25,7 @@
 #include <linux/pvclock_gtod.h>
 #include <linux/clocksource.h>
 #include <linux/irqbypass.h>
+#include <linux/hyperv.h>
 
 #include <asm/pvclock-abi.h>
 #include <asm/desc.h>
@@ -374,10 +375,23 @@ struct kvm_mtrr {
 	struct list_head head;
 };
 
+/* Hyper-V synthetic interrupt controller */
+struct kvm_vcpu_hv_synic {
+	u64 version;
+	u64 control;
+	u64 msg_page;
+	u64 evt_page;
+	atomic64_t sint[HV_SYNIC_SINT_COUNT];
+	atomic_t sint_to_gsi[HV_SYNIC_SINT_COUNT];
+	DECLARE_BITMAP(auto_eoi_bitmap, 256);
+	DECLARE_BITMAP(vec_bitmap, 256);
+};
+
 /* Hyper-V per vcpu emulation context */
 struct kvm_vcpu_hv {
 	u64 hv_vapic;
 	s64 runtime_offset;
+	struct kvm_vcpu_hv_synic synic;
 };
 
 struct kvm_vcpu_arch {
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 62cf8c9..15c3c02 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -23,13 +23,265 @@
 
 #include "x86.h"
 #include "lapic.h"
+#include "ioapic.h"
 #include "hyperv.h"
 
 #include <linux/kvm_host.h>
+#include <asm/apicdef.h>
 #include <trace/events/kvm.h>
 
 #include "trace.h"
 
+static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
+{
+	return atomic64_read(&synic->sint[sint]);
+}
+
+static inline int synic_get_sint_vector(u64 sint_value)
+{
+	if (sint_value & HV_SYNIC_SINT_MASKED)
+		return -1;
+	return sint_value & HV_SYNIC_SINT_VECTOR_MASK;
+}
+
+static bool synic_has_active_vector(struct kvm_vcpu_hv_synic *synic,
+				    int vector, int sint_to_skip, int sint_mask)
+{
+	u64 sint_value;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
+		if (i == sint_to_skip)
+			continue;
+		sint_value = synic_read_sint(synic, i);
+		if ((synic_get_sint_vector(sint_value) == vector) &&
+		    ((sint_mask == 0) || (sint_value & sint_mask)))
+			return true;
+	}
+	return false;
+}
+
+static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint, u64 data)
+{
+	int vector;
+
+	vector = data & HV_SYNIC_SINT_VECTOR_MASK;
+	if (vector < 16)
+		return 1;
+	/*
+	 * Guest may configure multiple SINTs to use the same vector, so
+	 * we maintain a bitmap of vectors handled by synic, and a
+	 * bitmap of vectors with auto-eoi behavoir.  The bitmaps are
+	 * updated here, and atomically queried on fast paths.
+	 */
+
+	if (!(data & HV_SYNIC_SINT_MASKED)) {
+		__set_bit(vector, synic->vec_bitmap);
+		if (data & HV_SYNIC_SINT_AUTO_EOI)
+			__set_bit(vector, synic->auto_eoi_bitmap);
+	} else {
+		if (!synic_has_active_vector(synic, vector, sint, 0))
+			__clear_bit(vector, synic->vec_bitmap);
+		if (!synic_has_active_vector(synic, vector, sint,
+					     HV_SYNIC_SINT_AUTO_EOI))
+			__clear_bit(vector, synic->auto_eoi_bitmap);
+	}
+
+	atomic64_set(&synic->sint[sint], data);
+	return 0;
+}
+
+static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
+			 u32 msr, u64 data, bool host)
+{
+	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
+	int ret;
+
+	vcpu_debug(vcpu, "set msr 0x%x 0x%llx host %d\n",
+		   msr, data, host);
+	ret = 0;
+	switch (msr) {
+	case HV_X64_MSR_SCONTROL:
+		synic->control = data;
+		break;
+	case HV_X64_MSR_SVERSION:
+		if (!host) {
+			ret = 1;
+			break;
+		}
+		synic->version = data;
+		break;
+	case HV_X64_MSR_SIEFP:
+		if (data & HV_SYNIC_SIEFP_ENABLE)
+			if (kvm_clear_guest(vcpu->kvm,
+					    data & PAGE_MASK, PAGE_SIZE)) {
+				ret = 1;
+				break;
+			}
+		synic->evt_page = data;
+		break;
+	case HV_X64_MSR_SIMP:
+		if (data & HV_SYNIC_SIMP_ENABLE)
+			if (kvm_clear_guest(vcpu->kvm,
+					    data & PAGE_MASK, PAGE_SIZE)) {
+				ret = 1;
+				break;
+			}
+		synic->msg_page = data;
+		break;
+	case HV_X64_MSR_EOM: {
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
+			kvm_notify_acked_hv_sint(vcpu, i);
+		break;
+	}
+	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
+		ret = synic_set_sint(synic, msr - HV_X64_MSR_SINT0, data);
+		break;
+	default:
+		ret = 1;
+		break;
+	}
+	return ret;
+}
+
+static int synic_get_msr(struct kvm_vcpu_hv_synic *synic, u32 msr, u64 *pdata)
+{
+	int ret;
+
+	ret = 0;
+	switch (msr) {
+	case HV_X64_MSR_SCONTROL:
+		*pdata = synic->control;
+		break;
+	case HV_X64_MSR_SVERSION:
+		*pdata = synic->version;
+		break;
+	case HV_X64_MSR_SIEFP:
+		*pdata = synic->evt_page;
+		break;
+	case HV_X64_MSR_SIMP:
+		*pdata = synic->msg_page;
+		break;
+	case HV_X64_MSR_EOM:
+		*pdata = 0;
+		break;
+	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
+		*pdata = atomic64_read(&synic->sint[msr - HV_X64_MSR_SINT0]);
+		break;
+	default:
+		ret = 1;
+		break;
+	}
+	return ret;
+}
+
+int synic_set_irq(struct kvm_vcpu_hv_synic *synic, u32 sint)
+{
+	struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
+	struct kvm_lapic_irq irq;
+	int ret, vector;
+
+	if (sint >= ARRAY_SIZE(synic->sint))
+		return -EINVAL;
+
+	vector = synic_get_sint_vector(synic_read_sint(synic, sint));
+	if (vector < 0)
+		return -ENOENT;
+
+	memset(&irq, 0, sizeof(irq));
+	irq.dest_id = kvm_apic_id(vcpu->arch.apic);
+	irq.dest_mode = APIC_DEST_PHYSICAL;
+	irq.delivery_mode = APIC_DM_FIXED;
+	irq.vector = vector;
+	irq.level = 1;
+
+	ret = kvm_irq_delivery_to_apic(vcpu->kvm, NULL, &irq, NULL);
+	vcpu_debug(vcpu, "set irq ret %d\n", ret);
+	return ret;
+}
+
+static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vcpu_id)
+{
+	struct kvm_vcpu *vcpu;
+
+	if (vcpu_id >= atomic_read(&kvm->online_vcpus))
+		return NULL;
+	vcpu = kvm_get_vcpu(kvm, vcpu_id);
+	if (!vcpu)
+		return NULL;
+
+	return vcpu_to_synic(vcpu);
+}
+
+int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vcpu_id, u32 sint)
+{
+	struct kvm_vcpu_hv_synic *synic;
+
+	synic = synic_get(kvm, vcpu_id);
+	if (!synic)
+		return -EINVAL;
+
+	return synic_set_irq(synic, sint);
+}
+
+void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector)
+{
+	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
+	int i;
+
+	vcpu_debug(vcpu, "synic eoi vec %d\n", vector);
+
+	for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
+		if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
+			kvm_notify_acked_hv_sint(vcpu, i);
+}
+
+int kvm_hv_get_sint_gsi(struct kvm_vcpu *vcpu, u32 sint)
+{
+	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
+	int gsi;
+
+	if (sint >= ARRAY_SIZE(synic->sint_to_gsi))
+		return -1;
+
+	gsi = atomic_read(&synic->sint_to_gsi[sint]);
+	return gsi;
+}
+
+int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vcpu_id, u32 sint, int gsi)
+{
+	struct kvm_vcpu_hv_synic *synic;
+
+	synic = synic_get(kvm, vcpu_id);
+	if (!synic)
+		return -EINVAL;
+
+	if (sint >= ARRAY_SIZE(synic->sint_to_gsi))
+		return -EINVAL;
+
+	atomic_set(&synic->sint_to_gsi[sint], gsi);
+	return 0;
+}
+
+static void synic_init(struct kvm_vcpu_hv_synic *synic)
+{
+	int i;
+
+	memset(synic, 0, sizeof(*synic));
+	synic->version = HV_SYNIC_VERSION_1;
+	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
+		atomic64_set(&synic->sint[i], HV_SYNIC_SINT_MASKED);
+		atomic_set(&synic->sint_to_gsi[i], -1);
+	}
+}
+
+void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	synic_init(vcpu_to_synic(vcpu));
+}
+
 static bool kvm_hv_msr_partition_wide(u32 msr)
 {
 	bool r = false;
@@ -226,6 +478,13 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 			return 1;
 		hv->runtime_offset = data - current_task_runtime_100ns();
 		break;
+	case HV_X64_MSR_SCONTROL:
+	case HV_X64_MSR_SVERSION:
+	case HV_X64_MSR_SIEFP:
+	case HV_X64_MSR_SIMP:
+	case HV_X64_MSR_EOM:
+	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
+		return synic_set_msr(vcpu_to_synic(vcpu), msr, data, host);
 	default:
 		vcpu_unimpl(vcpu, "Hyper-V uhandled wrmsr: 0x%x data 0x%llx\n",
 			    msr, data);
@@ -304,6 +563,13 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 	case HV_X64_MSR_VP_RUNTIME:
 		data = current_task_runtime_100ns() + hv->runtime_offset;
 		break;
+	case HV_X64_MSR_SCONTROL:
+	case HV_X64_MSR_SVERSION:
+	case HV_X64_MSR_SIEFP:
+	case HV_X64_MSR_SIMP:
+	case HV_X64_MSR_EOM:
+	case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
+		return synic_get_msr(vcpu_to_synic(vcpu), msr, pdata);
 	default:
 		vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
 		return 1;
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index c7bce55..cd3a483 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -29,4 +29,24 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata);
 bool kvm_hv_hypercall_enabled(struct kvm *kvm);
 int kvm_hv_hypercall(struct kvm_vcpu *vcpu);
 
+int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vcpu_id, u32 sint);
+void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector);
+
+static inline struct kvm_vcpu_hv_synic *vcpu_to_synic(struct kvm_vcpu *vcpu)
+{
+	return &vcpu->arch.hyperv.synic;
+}
+
+static inline struct kvm_vcpu *synic_to_vcpu(struct kvm_vcpu_hv_synic *synic)
+{
+	struct kvm_vcpu_hv *hv;
+	struct kvm_vcpu_arch *arch;
+
+	hv = container_of(synic, struct kvm_vcpu_hv, synic);
+	arch = container_of(hv, struct kvm_vcpu_arch, hyperv);
+	return container_of(arch, struct kvm_vcpu, arch);
+}
+
+void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu);
+
 #endif
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index c892289..d26baf8 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -33,6 +33,8 @@
 
 #include "lapic.h"
 
+#include "hyperv.h"
+
 static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
 			   struct kvm *kvm, int irq_source_id, int level,
 			   bool line_status)
@@ -123,6 +125,15 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 	return kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);
 }
 
+int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
+		    struct kvm *kvm, int irq_source_id, int level,
+		    bool line_status)
+{
+	if (!level)
+		return -1;
+
+	return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint);
+}
 
 static int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e,
 			 struct kvm *kvm)
@@ -289,6 +300,11 @@ int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
 		e->msi.address_hi = ue->u.msi.address_hi;
 		e->msi.data = ue->u.msi.data;
 		break;
+	case KVM_IRQ_ROUTING_HV_SINT:
+		e->set = kvm_hv_set_sint;
+		e->hv_sint.vcpu = ue->u.hv_sint.vcpu;
+		e->hv_sint.sint = ue->u.hv_sint.sint;
+		break;
 	default:
 		goto out;
 	}
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 944b38a..63edbec 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -41,6 +41,7 @@
 #include "trace.h"
 #include "x86.h"
 #include "cpuid.h"
+#include "hyperv.h"
 
 #ifndef CONFIG_X86_64
 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
@@ -128,11 +129,6 @@ static inline int apic_enabled(struct kvm_lapic *apic)
 	(LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
 	 APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)
 
-static inline int kvm_apic_id(struct kvm_lapic *apic)
-{
-	return (kvm_apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
-}
-
 /* The logical map is definitely wrong if we have multiple
  * modes at the same time.  (Physical map is always right.)
  */
@@ -972,6 +968,9 @@ static int apic_set_eoi(struct kvm_lapic *apic)
 	apic_clear_isr(vector, apic);
 	apic_update_ppr(apic);
 
+	if (test_bit(vector, vcpu_to_synic(apic->vcpu)->vec_bitmap))
+		kvm_hv_synic_send_eoi(apic->vcpu, vector);
+
 	kvm_ioapic_send_eoi(apic, vector);
 	kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
 	return vector;
@@ -1881,6 +1880,12 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
 	apic_set_isr(vector, apic);
 	apic_update_ppr(apic);
 	apic_clear_irr(vector, apic);
+
+	if (test_bit(vector, vcpu_to_synic(vcpu)->auto_eoi_bitmap)) {
+		apic_clear_isr(vector, apic);
+		apic_update_ppr(apic);
+	}
+
 	return vector;
 }
 
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index fde8e35d..6c64090 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -164,6 +164,11 @@ static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu)
 	return kvm_vcpu_has_lapic(vcpu) && test_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
 }
 
+static inline int kvm_apic_id(struct kvm_lapic *apic)
+{
+	return (kvm_apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
+}
+
 bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
 
 void wait_lapic_expire(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2d2c9bb..7580e9c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -958,6 +958,7 @@ static u32 emulated_msrs[] = {
 	HV_X64_MSR_RESET,
 	HV_X64_MSR_VP_INDEX,
 	HV_X64_MSR_VP_RUNTIME,
+	HV_X64_MSR_SCONTROL,
 	HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
 	MSR_KVM_PV_EOI_EN,
 
@@ -2440,6 +2441,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_HYPERV:
 	case KVM_CAP_HYPERV_VAPIC:
 	case KVM_CAP_HYPERV_SPIN:
+	case KVM_CAP_HYPERV_SYNIC:
 	case KVM_CAP_PCI_SEGMENT:
 	case KVM_CAP_DEBUGREGS:
 	case KVM_CAP_X86_ROBUST_SINGLESTEP:
@@ -7453,6 +7455,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
 	vcpu->arch.pending_external_vector = -1;
 
+	kvm_hv_vcpu_init(vcpu);
+
 	return 0;
 
 fail_free_mce_banks:
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 3d70e36..3782636 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -63,9 +63,6 @@ enum hv_cpuid_function {
 /* Define version of the synthetic interrupt controller. */
 #define HV_SYNIC_VERSION		(1)
 
-/* Define the expected SynIC version. */
-#define HV_SYNIC_VERSION_1		(0x1)
-
 /* Define synthetic interrupt controller message constants. */
 #define HV_MESSAGE_SIZE			(256)
 #define HV_MESSAGE_PAYLOAD_BYTE_COUNT	(240)
@@ -105,8 +102,6 @@ enum hv_message_type {
 	HVMSG_X64_LEGACY_FP_ERROR		= 0x80010005
 };
 
-/* Define the number of synthetic interrupt sources. */
-#define HV_SYNIC_SINT_COUNT		(16)
 #define HV_SYNIC_STIMER_COUNT		(4)
 
 /* Define invalid partition identifier. */
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9596a2f..30fac73 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -318,6 +318,11 @@ struct kvm_s390_adapter_int {
 	u32 adapter_id;
 };
 
+struct kvm_hv_sint {
+	u32 vcpu;
+	u32 sint;
+};
+
 struct kvm_kernel_irq_routing_entry {
 	u32 gsi;
 	u32 type;
@@ -331,6 +336,7 @@ struct kvm_kernel_irq_routing_entry {
 		} irqchip;
 		struct msi_msg msi;
 		struct kvm_s390_adapter_int adapter;
+		struct kvm_hv_sint hv_sint;
 	};
 	struct hlist_node link;
 };
@@ -822,14 +828,20 @@ struct kvm_irq_ack_notifier {
 int kvm_irq_map_gsi(struct kvm *kvm,
 		    struct kvm_kernel_irq_routing_entry *entries, int gsi);
 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin);
+int kvm_hv_get_sint_gsi(struct kvm_vcpu *vcpu, u32 sint);
+int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vcpu_id, u32 sint, int gsi);
 
 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 		bool line_status);
 int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level);
 int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm *kvm,
 		int irq_source_id, int level, bool line_status);
+int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *irq_entry,
+		    struct kvm *kvm, int irq_source_id, int level,
+		    bool line_status);
 bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
+void kvm_notify_acked_hv_sint(struct kvm_vcpu *vcpu, u32 sint);
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h
index e4c0a35..8a63ea7 100644
--- a/include/uapi/linux/hyperv.h
+++ b/include/uapi/linux/hyperv.h
@@ -395,4 +395,16 @@ struct hv_kvp_ip_msg {
 	struct hv_kvp_ipaddr_value      kvp_ip_val;
 } __attribute__((packed));
 
+/* Define the number of synthetic interrupt sources. */
+#define HV_SYNIC_SINT_COUNT		(16)
+/* Define the expected SynIC version. */
+#define HV_SYNIC_VERSION_1		(0x1)
+
+#define HV_SYNIC_CONTROL_ENABLE		(1ULL << 0)
+#define HV_SYNIC_SIMP_ENABLE		(1ULL << 0)
+#define HV_SYNIC_SIEFP_ENABLE		(1ULL << 0)
+#define HV_SYNIC_SINT_MASKED		(1ULL << 16)
+#define HV_SYNIC_SINT_AUTO_EOI		(1ULL << 17)
+#define HV_SYNIC_SINT_VECTOR_MASK	(0xFF)
+
 #endif /* _UAPI_HYPERV_H */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 03f3618..27ce460 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -831,6 +831,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_GUEST_DEBUG_HW_WPS 120
 #define KVM_CAP_SPLIT_IRQCHIP 121
 #define KVM_CAP_IOEVENTFD_ANY_LENGTH 122
+#define KVM_CAP_HYPERV_SYNIC 123
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -854,10 +855,16 @@ struct kvm_irq_routing_s390_adapter {
 	__u32 adapter_id;
 };
 
+struct kvm_irq_routing_hv_sint {
+	__u32 vcpu;
+	__u32 sint;
+};
+
 /* gsi routing entry types */
 #define KVM_IRQ_ROUTING_IRQCHIP 1
 #define KVM_IRQ_ROUTING_MSI 2
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
+#define KVM_IRQ_ROUTING_HV_SINT 4
 
 struct kvm_irq_routing_entry {
 	__u32 gsi;
@@ -868,6 +875,7 @@ struct kvm_irq_routing_entry {
 		struct kvm_irq_routing_irqchip irqchip;
 		struct kvm_irq_routing_msi msi;
 		struct kvm_irq_routing_s390_adapter adapter;
+		struct kvm_irq_routing_hv_sint hv_sint;
 		__u32 pad[8];
 	} u;
 };
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 6bd1c9b..02fbe7f 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -2527,3 +2527,21 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 {
 	return 0;
 }
+
+/* Hyper-V Synic not implemented */
+int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
+		    struct kvm *kvm, int irq_source_id, int level,
+		    bool line_status)
+{
+	return -ENOTSUP;
+}
+
+int kvm_hv_get_sint_gsi(struct kvm_vcpu *vcpu, u32 sint)
+{
+	return -ENOTSUP;
+}
+
+int kvm_hv_set_sint_gsi(struct kvm *kvm, u32 vcpu_id, u32 sint, int gsi)
+{
+	return -ENOTSUP;
+}
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index b637965..0d7b705 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -192,11 +192,19 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
 			irq = irqfd->irq_entry;
 		} while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
 		/* An event has been signaled, inject an interrupt */
-		if (irq.type == KVM_IRQ_ROUTING_MSI)
+		switch (irq.type) {
+		case KVM_IRQ_ROUTING_MSI:
 			kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
 					false);
-		else
+			break;
+		case KVM_IRQ_ROUTING_HV_SINT:
+			kvm_hv_set_sint(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
+					1, false);
+			break;
+		default:
 			schedule_work(&irqfd->inject);
+			break;
+		}
 		srcu_read_unlock(&kvm->irq_srcu, idx);
 	}
 
@@ -248,8 +256,9 @@ static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
 
 	e = entries;
 	for (i = 0; i < n_entries; ++i, ++e) {
-		/* Only fast-path MSI. */
-		if (e->type == KVM_IRQ_ROUTING_MSI)
+		/* Fast-path MSI and Hyper-V sint */
+		if (e->type == KVM_IRQ_ROUTING_MSI ||
+		    e->type == KVM_IRQ_ROUTING_HV_SINT)
 			irqfd->irq_entry = *e;
 	}
 
@@ -471,6 +480,24 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 	srcu_read_unlock(&kvm->irq_srcu, idx);
 }
 
+void kvm_notify_acked_hv_sint(struct kvm_vcpu *vcpu, u32 sint)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_irq_ack_notifier *kian;
+	int gsi, idx;
+
+	vcpu_debug(vcpu, "synic acked sint %d\n", sint);
+
+	idx = srcu_read_lock(&kvm->irq_srcu);
+	gsi = kvm_hv_get_sint_gsi(vcpu, sint);
+	if (gsi != -1)
+		hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
+					 link)
+			if (kian->gsi == gsi)
+				kian->irq_acked(kian);
+	srcu_read_unlock(&kvm->irq_srcu, idx);
+}
+
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian)
 {
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 716a1c4..1cf3d92 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -144,11 +144,13 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 
 	/*
 	 * Do not allow GSI to be mapped to the same irqchip more than once.
-	 * Allow only one to one mapping between GSI and MSI.
+	 * Allow only one to one mapping between GSI and MSI/Hyper-V SINT.
 	 */
 	hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
 		if (ei->type == KVM_IRQ_ROUTING_MSI ||
 		    ue->type == KVM_IRQ_ROUTING_MSI ||
+		    ei->type == KVM_IRQ_ROUTING_HV_SINT ||
+		    ue->type == KVM_IRQ_ROUTING_HV_SINT ||
 		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 			return r;
 
@@ -166,6 +168,25 @@ out:
 	return r;
 }
 
+static void kvm_irq_update_hv_sint_gsi(struct kvm *kvm)
+{
+	struct kvm_irq_routing_table *irq_rt;
+	struct kvm_kernel_irq_routing_entry *e;
+	u32 gsi;
+
+	irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
+					lockdep_is_held(&kvm->irq_lock));
+
+	for (gsi = 0; gsi < irq_rt->nr_rt_entries; gsi++) {
+		hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
+			if (e->type == KVM_IRQ_ROUTING_HV_SINT)
+				kvm_hv_set_sint_gsi(kvm, e->hv_sint.vcpu,
+						    e->hv_sint.sint,
+						    gsi);
+		}
+	}
+}
+
 int kvm_set_irq_routing(struct kvm *kvm,
 			const struct kvm_irq_routing_entry *ue,
 			unsigned nr,
@@ -219,6 +240,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
 	old = kvm->irq_routing;
 	rcu_assign_pointer(kvm->irq_routing, new);
 	kvm_irq_routing_update(kvm);
+	kvm_irq_update_hv_sint_gsi(kvm);
 	mutex_unlock(&kvm->irq_lock);
 
 	kvm_arch_irq_routing_update(kvm);
-- 
2.1.4

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Paolo Bonzini]

Christian, the question for you is towards the end...

On 09/10/2015 15:39, Denis V. Lunev wrote:
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 62cf8c9..15c3c02 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -23,13 +23,265 @@
>  
>  #include "x86.h"
>  #include "lapic.h"
> +#include "ioapic.h"
>  #include "hyperv.h"
>  
>  #include <linux/kvm_host.h>
> +#include <asm/apicdef.h>
>  #include <trace/events/kvm.h>
>  
>  #include "trace.h"
>  
> +static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
> +{
> +	return atomic64_read(&synic->sint[sint]);
> +}
> +
> +static inline int synic_get_sint_vector(u64 sint_value)
> +{
> +	if (sint_value & HV_SYNIC_SINT_MASKED)
> +		return -1;
> +	return sint_value & HV_SYNIC_SINT_VECTOR_MASK;
> +}
> +
> +static bool synic_has_active_vector(struct kvm_vcpu_hv_synic *synic,
> +				    int vector, int sint_to_skip, int sint_mask)
> +{
> +	u64 sint_value;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
> +		if (i == sint_to_skip)
> +			continue;
> +		sint_value = synic_read_sint(synic, i);
> +		if ((synic_get_sint_vector(sint_value) == vector) &&
> +		    ((sint_mask == 0) || (sint_value & sint_mask)))

Coding style, no parentheses around && or ||:

		if (synic_get_sint_vector(sint_value) == vector &&
		    (sint_mask == 0 || sint_value & sint_mask)


> +			return true;
> +	}
> +	return false;
> +}
> +
> +static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint, u64 data)
> +{
> +	int vector;
> +
> +	vector = data & HV_SYNIC_SINT_VECTOR_MASK;
> +	if (vector < 16)
> +		return 1;
> +	/*
> +	 * Guest may configure multiple SINTs to use the same vector, so
> +	 * we maintain a bitmap of vectors handled by synic, and a
> +	 * bitmap of vectors with auto-eoi behavoir.  The bitmaps are

Typo (behavior).

> +	 * updated here, and atomically queried on fast paths.
> +	 */
> +
> +	if (!(data & HV_SYNIC_SINT_MASKED)) {
> +		__set_bit(vector, synic->vec_bitmap);
> +		if (data & HV_SYNIC_SINT_AUTO_EOI)
> +			__set_bit(vector, synic->auto_eoi_bitmap);
> +	} else {
> +		if (!synic_has_active_vector(synic, vector, sint, 0))
> +			__clear_bit(vector, synic->vec_bitmap);
> +		if (!synic_has_active_vector(synic, vector, sint,
> +					     HV_SYNIC_SINT_AUTO_EOI))
> +			__clear_bit(vector, synic->auto_eoi_bitmap);

I think you could do the clears after the atomic64_set?  Then you do not
need anymore the third argument to synic_has_active_vector.  Actually I
think it's simpler if you just make two functions,
synic_is_vector_connected and synic_is_vector_auto_eoi.  There is some
code duplication, but the functions are trivial.

> @@ -123,6 +125,15 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
>  	return kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);
>  }
>  
> +int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
> +		    struct kvm *kvm, int irq_source_id, int level,
> +		    bool line_status)
> +{
> +	if (!level)
> +		return -1;
> +
> +	return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint);
> +}
>  
>  static int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e,
>  			 struct kvm *kvm)
> @@ -289,6 +300,11 @@ int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
>  		e->msi.address_hi = ue->u.msi.address_hi;
>  		e->msi.data = ue->u.msi.data;
>  		break;
> +	case KVM_IRQ_ROUTING_HV_SINT:
> +		e->set = kvm_hv_set_sint;
> +		e->hv_sint.vcpu = ue->u.hv_sint.vcpu;
> +		e->hv_sint.sint = ue->u.hv_sint.sint;
> +		break;
>  	default:
>  		goto out;
>  	}
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 944b38a..63edbec 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -41,6 +41,7 @@
>  #include "trace.h"
>  #include "x86.h"
>  #include "cpuid.h"
> +#include "hyperv.h"
>  
>  #ifndef CONFIG_X86_64
>  #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
> @@ -128,11 +129,6 @@ static inline int apic_enabled(struct kvm_lapic *apic)
>  	(LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
>  	 APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)
>  
> -static inline int kvm_apic_id(struct kvm_lapic *apic)
> -{
> -	return (kvm_apic_get_reg(apic, APIC_ID) >> 24) & 0xff;
> -}
> -
>  /* The logical map is definitely wrong if we have multiple
>   * modes at the same time.  (Physical map is always right.)
>   */
> @@ -972,6 +968,9 @@ static int apic_set_eoi(struct kvm_lapic *apic)
>  	apic_clear_isr(vector, apic);
>  	apic_update_ppr(apic);
>  
> +	if (test_bit(vector, vcpu_to_synic(apic->vcpu)->vec_bitmap))
> +		kvm_hv_synic_send_eoi(apic->vcpu, vector);
> +
>  	kvm_ioapic_send_eoi(apic, vector);
>  	kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
>  	return vector;

You need to add SYNIC vectors to the EOI exit bitmap, so that APICv
(Xeon E5 or higher, Ivy Bridge or newer) is handled correctly.  You also
need to check the auto EOI exit bitmap in __apic_accept_irq, and avoid
going through kvm_x86_ops->deliver_posted_interrupt for auto EOI
vectors.  Something like

	if (kvm_x86_ops->deliver_posted_interrupt &&
	    !test_bit(...))

in place of the existing "if (kvm_x86_ops->deliver_posted_interrupt)".

I really don't like this auto-EOI extension, but I guess that's the
spec. :( If it wasn't for it, you could do everything very easily in
userspace using Google's proposed MSR exit.

> diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
> index 3d70e36..3782636 100644
> --- a/drivers/hv/hyperv_vmbus.h
> +++ b/drivers/hv/hyperv_vmbus.h
> @@ -63,9 +63,6 @@ enum hv_cpuid_function {
>  /* Define version of the synthetic interrupt controller. */
>  #define HV_SYNIC_VERSION		(1)
>  
> -/* Define the expected SynIC version. */
> -#define HV_SYNIC_VERSION_1		(0x1)
> -
>  /* Define synthetic interrupt controller message constants. */
>  #define HV_MESSAGE_SIZE			(256)
>  #define HV_MESSAGE_PAYLOAD_BYTE_COUNT	(240)
> @@ -105,8 +102,6 @@ enum hv_message_type {
>  	HVMSG_X64_LEGACY_FP_ERROR		= 0x80010005
>  };
>  
> -/* Define the number of synthetic interrupt sources. */
> -#define HV_SYNIC_SINT_COUNT		(16)
>  #define HV_SYNIC_STIMER_COUNT		(4)
>  
>  /* Define invalid partition identifier. */

Please make these changes to drivers/hv and the uapi/ headers a separate
patch.  I think the right header to move the constants to is not
include/uapi/linux/hyperv.h, but rather arch/x86/include/uapi/asm/hyperv.h.

> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index b637965..0d7b705 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -192,11 +192,19 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
>  			irq = irqfd->irq_entry;
>  		} while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
>  		/* An event has been signaled, inject an interrupt */
> -		if (irq.type == KVM_IRQ_ROUTING_MSI)
> +		switch (irq.type) {
> +		case KVM_IRQ_ROUTING_MSI:
>  			kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
>  					false);
> -		else
> +			break;
> +		case KVM_IRQ_ROUTING_HV_SINT:
> +			kvm_hv_set_sint(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
> +					1, false);
> +			break;
> +		default:
>  			schedule_work(&irqfd->inject);
> +			break;
> +		}

Please make a new function kvm_arch_set_irq.  The new function can
return true if the interrupt has been injected, and -EWOULDBLOCK if the
caller should call schedule_work().  The default implementation can be a
weak function in virt/kvm/eventfd.c.

> @@ -248,8 +256,9 @@ static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
>  
>  	e = entries;
>  	for (i = 0; i < n_entries; ++i, ++e) {
> -		/* Only fast-path MSI. */
> -		if (e->type == KVM_IRQ_ROUTING_MSI)
> +		/* Fast-path MSI and Hyper-V sint */
> +		if (e->type == KVM_IRQ_ROUTING_MSI ||
> +		    e->type == KVM_IRQ_ROUTING_HV_SINT)
>  			irqfd->irq_entry = *e;
>  	}

I think this "for" is unnecessary altogether.  Instead, we should do:

	if (n_entries == 1)
		irqfd->irq_entry = *e;
	else
		irqfd->irq_entry.type = 0;

Because any other value for irq_entry.type will just trigger
schedule_work(&irqfd->inject).  Please make it a separate patch, however.

> @@ -471,6 +480,24 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
>  	srcu_read_unlock(&kvm->irq_srcu, idx);
>  }
>  
> +void kvm_notify_acked_hv_sint(struct kvm_vcpu *vcpu, u32 sint)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	struct kvm_irq_ack_notifier *kian;
> +	int gsi, idx;
> +
> +	vcpu_debug(vcpu, "synic acked sint %d\n", sint);
> +
> +	idx = srcu_read_lock(&kvm->irq_srcu);
> +	gsi = kvm_hv_get_sint_gsi(vcpu, sint);
> +	if (gsi != -1)
> +		hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
> +					 link)
> +			if (kian->gsi == gsi)
> +				kian->irq_acked(kian);
> +	srcu_read_unlock(&kvm->irq_srcu, idx);
> +}

Please move the hlist_for_each_entry_rcu to a new function
kvm_notify_acked_gsi.  kvm_notify_acked_irq can use the new function as
well.  Then this function can be moved to arch/x86/kvm/hyperv.c.

> +
>  void kvm_register_irq_ack_notifier(struct kvm *kvm,
>  				   struct kvm_irq_ack_notifier *kian)
>  {
> diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
> index 716a1c4..1cf3d92 100644
> --- a/virt/kvm/irqchip.c
> +++ b/virt/kvm/irqchip.c
> @@ -144,11 +144,13 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
>  
>  	/*
>  	 * Do not allow GSI to be mapped to the same irqchip more than once.
> -	 * Allow only one to one mapping between GSI and MSI.
> +	 * Allow only one to one mapping between GSI and MSI/Hyper-V SINT.
>  	 */
>  	hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
>  		if (ei->type == KVM_IRQ_ROUTING_MSI ||
>  		    ue->type == KVM_IRQ_ROUTING_MSI ||
> +		    ei->type == KVM_IRQ_ROUTING_HV_SINT ||
> +		    ue->type == KVM_IRQ_ROUTING_HV_SINT ||
>  		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
>  			return r;

Christian, what's the desired behavior for s390 adapter interrupts here?
 Should this actually become

	if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
	    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
	    ue->u.irqchip.irqchip == ei->irqchip.irqchip)

?  This would make sense, in that you shouldn't access "struct
kvm_irq_routing_irqchip" unless the type is set to
KVM_IRQ_ROUTING_IRQCHIP.  Again, separate patch please.

>  int kvm_set_irq_routing(struct kvm *kvm,
>  			const struct kvm_irq_routing_entry *ue,
>  			unsigned nr,
> @@ -219,6 +240,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
>  	old = kvm->irq_routing;
>  	rcu_assign_pointer(kvm->irq_routing, new);
>  	kvm_irq_routing_update(kvm);
> +	kvm_irq_update_hv_sint_gsi(kvm);

Please call this function kvm_arch_irq_routing_update, and (in a
separate patch) rename the existing kvm_arch_irq_routing_update to
kvm_arch_post_irq_routing_update.

Paolo

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Roman Kagan]

On Fri, Oct 09, 2015 at 04:42:33PM +0200, Paolo Bonzini wrote:
> You need to add SYNIC vectors to the EOI exit bitmap, so that APICv
> (Xeon E5 or higher, Ivy Bridge or newer) is handled correctly.  You also
> need to check the auto EOI exit bitmap in __apic_accept_irq, and avoid
> going through kvm_x86_ops->deliver_posted_interrupt for auto EOI
> vectors.  Something like
> 
> 	if (kvm_x86_ops->deliver_posted_interrupt &&
> 	    !test_bit(...))
> 
> in place of the existing "if (kvm_x86_ops->deliver_posted_interrupt)".

Indeed, missed that path, thanks!

> I really don't like this auto-EOI extension, but I guess that's the
> spec. :( If it wasn't for it, you could do everything very easily in
> userspace using Google's proposed MSR exit.

I guess you're right.  We'd probably have to (ab)use MSI for SINT
delivery, though.  Anyway the need to implement auto-EOI rules that out.

Thanks for the quick review, we'll try to address your comments in the
next round.

Roman.

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Paolo Bonzini]

On 09/10/2015 17:53, Roman Kagan wrote:
> > I really don't like this auto-EOI extension, but I guess that's the
> > spec. :( If it wasn't for it, you could do everything very easily in
> > userspace using Google's proposed MSR exit.
> I guess you're right.  We'd probably have to (ab)use MSI for SINT
> delivery, though.

Not really an issue, as MSI on x86 is really just the external entry
point into the LAPIC, it makes sense that it be the external interface
into KVM's virtualized LAPIC.  Userspace split irqchip is (ab)using MSI
routes the same way.

> Anyway the need to implement auto-EOI rules that out.

Yup.  I look forward to reviewing v2!

Paolo

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Christian Borntraeger]

Am 09.10.2015 um 16:42 schrieb Paolo Bonzini:
> Christian, the question for you is towards the end...



[....]
> 
>> --- a/virt/kvm/irqchip.c
>> +++ b/virt/kvm/irqchip.c
>> @@ -144,11 +144,13 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
>>  
>>  	/*
>>  	 * Do not allow GSI to be mapped to the same irqchip more than once.
>> -	 * Allow only one to one mapping between GSI and MSI.
>> +	 * Allow only one to one mapping between GSI and MSI/Hyper-V SINT.
>>  	 */
>>  	hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
>>  		if (ei->type == KVM_IRQ_ROUTING_MSI ||
>>  		    ue->type == KVM_IRQ_ROUTING_MSI ||
>> +		    ei->type == KVM_IRQ_ROUTING_HV_SINT ||
>> +		    ue->type == KVM_IRQ_ROUTING_HV_SINT ||
>>  		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
>>  			return r;
> 
> Christian, what's the desired behavior for s390 adapter interrupts here?
>  Should this actually become
> 
> 	if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
> 	    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
> 	    ue->u.irqchip.irqchip == ei->irqchip.irqchip)

Hmm, this is the failure path if we already have one routing entry, Right?
This will work with virtio ccw as we only setup one route, but I am not
sure about the upcoming PCI irqfd support which might add a 2nd adapter
route.

Adding Conny, Jens,Not sure about PC, 
As soon as we wire up the PCI irgfd, we want to register a 2nd route for
the same irqchip via flic, which will also be of type 
KVM_IRQ_ROUTING_S390_ADAPTER. Correct?

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Cornelia Huck]

On Mon, 12 Oct 2015 09:54:41 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> Am 09.10.2015 um 16:42 schrieb Paolo Bonzini:
> > Christian, the question for you is towards the end...
> 
> 
> 
> [....]
> > 
> >> --- a/virt/kvm/irqchip.c
> >> +++ b/virt/kvm/irqchip.c
> >> @@ -144,11 +144,13 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
> >>  
> >>  	/*
> >>  	 * Do not allow GSI to be mapped to the same irqchip more than once.
> >> -	 * Allow only one to one mapping between GSI and MSI.
> >> +	 * Allow only one to one mapping between GSI and MSI/Hyper-V SINT.
> >>  	 */
> >>  	hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
> >>  		if (ei->type == KVM_IRQ_ROUTING_MSI ||
> >>  		    ue->type == KVM_IRQ_ROUTING_MSI ||
> >> +		    ei->type == KVM_IRQ_ROUTING_HV_SINT ||
> >> +		    ue->type == KVM_IRQ_ROUTING_HV_SINT ||
> >>  		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
> >>  			return r;
> > 
> > Christian, what's the desired behavior for s390 adapter interrupts here?
> >  Should this actually become
> > 
> > 	if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
> > 	    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
> > 	    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
> 
> Hmm, this is the failure path if we already have one routing entry, Right?
> This will work with virtio ccw as we only setup one route, but I am not
> sure about the upcoming PCI irqfd support which might add a 2nd adapter
> route.
> 
> Adding Conny, Jens,Not sure about PC, 
> As soon as we wire up the PCI irgfd, we want to register a 2nd route for
> the same irqchip via flic, which will also be of type 
> KVM_IRQ_ROUTING_S390_ADAPTER. Correct?

It's a bit different. The kernel basically does not see msi routes for
s390 pci at all, as qemu already transforms the msi route into an
adapter route before registering it (see kvm_arch_fixup_msi_route() in
qemu's target-s390x/kvm.c). So, in the end, all s390 kernels end up
using adapter routes, and none of them are duplicate (just one irqchip).

Going back to Paolo's original question, I think changing the check
to !KVM_IRQ_ROUTING_IRQCHIP makes sense, if I understand the code
correctly. They seem to be the only special one.

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Paolo Bonzini]

On 12/10/2015 10:48, Cornelia Huck wrote:
> Going back to Paolo's original question, I think changing the check
> to !KVM_IRQ_ROUTING_IRQCHIP makes sense, if I understand the code
> correctly. They seem to be the only special one.

Great.  Roman, Denis, can you do this then?

Thanks,

Paolo

Re: [Qemu-devel] [PATCH 1/2] kvm/x86: Hyper-V synthetic interrupt controller

[Roman Kagan]

On Mon, Oct 12, 2015 at 10:58:36AM +0200, Paolo Bonzini wrote:
> On 12/10/2015 10:48, Cornelia Huck wrote:
> > Going back to Paolo's original question, I think changing the check
> > to !KVM_IRQ_ROUTING_IRQCHIP makes sense, if I understand the code
> > correctly. They seem to be the only special one.
> 
> Great.  Roman, Denis, can you do this then?

Sure, gonna be in the next round.

Thanks,
Roman.

[Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Denis V. Lunev]

From: Andrey Smetanin <asmetanin@virtuozzo.com>

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

Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtiozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
---
 Documentation/virtual/kvm/api.txt |  6 ++++++
 arch/x86/include/asm/kvm_host.h   |  1 +
 arch/x86/kvm/hyperv.c             | 17 +++++++++++++++++
 arch/x86/kvm/x86.c                |  6 ++++++
 include/linux/kvm_host.h          |  1 +
 include/uapi/linux/kvm.h          | 17 +++++++++++++++++
 6 files changed, 48 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 34cc068..cffe670 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3331,6 +3331,12 @@ 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.
 
+		/* KVM_EXIT_HYPERV */
+                struct kvm_hyperv_exit hyperv;
+Indicates that the VCPU's exits into userspace to process some tasks
+related with Hyper-V emulation. Currently used to synchronize modified
+Hyper-V synic state with 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 e614a543..f515e01 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -392,6 +392,7 @@ 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 15c3c02..174ce041 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -91,6 +91,20 @@ static int synic_set_sint(struct kvm_vcpu_hv_synic *synic, int sint, u64 data)
 	return 0;
 }
 
+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)
 {
@@ -103,6 +117,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
 	switch (msr) {
 	case HV_X64_MSR_SCONTROL:
 		synic->control = data;
+		synic_exit(synic, msr);
 		break;
 	case HV_X64_MSR_SVERSION:
 		if (!host) {
@@ -119,6 +134,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
 				break;
 			}
 		synic->evt_page = data;
+		synic_exit(synic, msr);
 		break;
 	case HV_X64_MSR_SIMP:
 		if (data & HV_SYNIC_SIMP_ENABLE)
@@ -128,6 +144,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
 				break;
 			}
 		synic->msg_page = data;
+		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 7580e9c..4c80d18 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6335,6 +6335,12 @@ 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 30fac73..d80b031 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];
 	};
-- 
2.1.4

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Paolo Bonzini]

On 09/10/2015 15:39, Denis V. Lunev wrote:
> From: Andrey Smetanin <asmetanin@virtuozzo.com>
> 
> A new vcpu exit is introduced to notify the userspace of the
> changes in Hyper-V synic configuraion triggered by guest writing to the
> corresponding MSRs.
> 
> Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
> Reviewed-by: Roman Kagan <rkagan@virtiozzo.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Vitaly Kuznetsov <vkuznets@redhat.com>
> CC: "K. Y. Srinivasan" <kys@microsoft.com>
> CC: Gleb Natapov <gleb@kernel.org>
> CC: Paolo Bonzini <pbonzini@redhat.com>

Why is this exit necessary?

Paolo

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Roman Kagan]

On Fri, Oct 09, 2015 at 04:41:15PM +0200, Paolo Bonzini wrote:
> On 09/10/2015 15:39, Denis V. Lunev wrote:
> > A new vcpu exit is introduced to notify the userspace of the
> > changes in Hyper-V synic configuraion triggered by guest writing to the
> > corresponding MSRs.
> 
> Why is this exit necessary?

The guest writes to synic-related MSRs and that should take "immediate"
effect.

E.g. it may decide to disable or relocate the message page by writing to
SIMP MSR.  The host is then supposed to stop accessing the old message
page before the vCPU proceeds to the next instruction.  Hence the exit,
to allow the userspace to react accordingly before reentering the guest.

Roman.

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Paolo Bonzini]

On 09/10/2015 16:53, Roman Kagan wrote:
>> > Why is this exit necessary?
> The guest writes to synic-related MSRs and that should take "immediate"
> effect.
> 
> E.g. it may decide to disable or relocate the message page by writing to
> SIMP MSR.  The host is then supposed to stop accessing the old message
> page before the vCPU proceeds to the next instruction.  Hence the exit,
> to allow the userspace to react accordingly before reentering the guest.

Ok, thanks!

Paolo

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1155 bytes --]

On 10/09/2015 07:39 AM, Denis V. Lunev wrote:
> From: Andrey Smetanin <asmetanin@virtuozzo.com>
> 
> A new vcpu exit is introduced to notify the userspace of the
> changes in Hyper-V synic configuraion triggered by guest writing to the

s/configuraion/configuration/
Is 'synic' intended?  Is it short for something (if so, spelling it out
may help)?


> +++ b/Documentation/virtual/kvm/api.txt
> @@ -3331,6 +3331,12 @@ 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.
>  
> +		/* KVM_EXIT_HYPERV */
> +                struct kvm_hyperv_exit hyperv;
> +Indicates that the VCPU's exits into userspace to process some tasks

s/VCPU's/VCPU/

> +related with Hyper-V emulation. Currently used to synchronize modified
> +Hyper-V synic state with userspace.

Again, is 'synic' intended?  Hmm, I see it throughout the patch, so it
looks intentional, but I keep trying to read it as a typo for 'sync'.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Eric Blake]

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On 10/12/2015 07:42 AM, Eric Blake wrote:
> On 10/09/2015 07:39 AM, Denis V. Lunev wrote:
>> From: Andrey Smetanin <asmetanin@virtuozzo.com>
>>
>> A new vcpu exit is introduced to notify the userspace of the
>> changes in Hyper-V synic configuraion triggered by guest writing to the
> 
> s/configuraion/configuration/
> Is 'synic' intended?  Is it short for something (if so, spelling it out
> may help)?

Ah, I see it now from patch 1/2: SYNthetic Interrupt Controller.

>> +related with Hyper-V emulation. Currently used to synchronize modified
>> +Hyper-V synic state with userspace.
> 
> Again, is 'synic' intended?  Hmm, I see it throughout the patch, so it
> looks intentional, but I keep trying to read it as a typo for 'sync'.

Don't know if SynIC would make it any easier to read?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Paolo Bonzini]

On 12/10/2015 15:42, Eric Blake wrote:
> > +related with Hyper-V emulation. Currently used to synchronize modified
> > +Hyper-V synic state with userspace.
>
> Again, is 'synic' intended?  Hmm, I see it throughout the patch, so it
> looks intentional, but I keep trying to read it as a typo for 'sync'.

It's synthetic interrupt controller, but indeed it's a bit obscure.
Perhaps we can change it in the docs to "Hyper-V synthetic interrupt state".

Paolo

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Denis V. Lunev]

On 10/12/2015 04:42 PM, Eric Blake wrote:
> On 10/09/2015 07:39 AM, Denis V. Lunev wrote:
>> From: Andrey Smetanin <asmetanin@virtuozzo.com>
>>
>> A new vcpu exit is introduced to notify the userspace of the
>> changes in Hyper-V synic configuraion triggered by guest writing to the
> s/configuraion/configuration/
> Is 'synic' intended?  Is it short for something (if so, spelling it out
> may help)?
>
>
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -3331,6 +3331,12 @@ 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.
>>   
>> +		/* KVM_EXIT_HYPERV */
>> +                struct kvm_hyperv_exit hyperv;
>> +Indicates that the VCPU's exits into userspace to process some tasks
> s/VCPU's/VCPU/
>
>> +related with Hyper-V emulation. Currently used to synchronize modified
>> +Hyper-V synic state with userspace.
> Again, is 'synic' intended?  Hmm, I see it throughout the patch, so it
> looks intentional, but I keep trying to read it as a typo for 'sync'.
>
this is not a typo :)

this is an abbreviation for synthetic interrupt controller,
pls compare with this

./arch/x86/include/uapi/asm/hyperv.h: * Basic SynIC MSRs 
(HV_X64_MSR_SCONTROL through HV_X64_MSR_EOM

Though there is some sense in the question itself. I think
that it would be better to keep naming it SynIC as
in the original kernel code.

Den

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[KY Srinivasan]

> -----Original Message-----
> From: Denis V. Lunev [mailto:den@openvz.org]
> Sent: Monday, October 12, 2015 6:46 AM
> To: Eric Blake <eblake@redhat.com>
> Cc: Gleb Natapov <gleb@kernel.org>; qemu-devel@nongnu.org;
> virtualization@lists.linux-foundation.org; rkagan@virtuozzo.com; Paolo
> Bonzini <pbonzini@redhat.com>; Andrey Smetanin
> <asmetanin@virtuozzo.com>; Vitaly Kuznetsov <vkuznets@redhat.com>; KY
> Srinivasan <kys@microsoft.com>
> Subject: Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit
> 
> On 10/12/2015 04:42 PM, Eric Blake wrote:
> > On 10/09/2015 07:39 AM, Denis V. Lunev wrote:
> >> From: Andrey Smetanin <asmetanin@virtuozzo.com>
> >>
> >> A new vcpu exit is introduced to notify the userspace of the
> >> changes in Hyper-V synic configuraion triggered by guest writing to the
> > s/configuraion/configuration/
> > Is 'synic' intended?  Is it short for something (if so, spelling it out
> > may help)?
> >
> >
> >> +++ b/Documentation/virtual/kvm/api.txt
> >> @@ -3331,6 +3331,12 @@ 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.
> >>
> >> +		/* KVM_EXIT_HYPERV */
> >> +                struct kvm_hyperv_exit hyperv;
> >> +Indicates that the VCPU's exits into userspace to process some tasks
> > s/VCPU's/VCPU/
> >
> >> +related with Hyper-V emulation. Currently used to synchronize modified
> >> +Hyper-V synic state with userspace.
> > Again, is 'synic' intended?  Hmm, I see it throughout the patch, so it
> > looks intentional, but I keep trying to read it as a typo for 'sync'.
> >
> this is not a typo :)

Yes; the Hyper-V public functional spec has chosen this name;
it stands for Synthetic Interrupt Controller.

K. Y

Re: [Qemu-devel] [PATCH 2/2] kvm/x86: Hyper-V kvm exit

[Roman Kagan]

On Mon, Oct 12, 2015 at 07:42:42AM -0600, Eric Blake wrote:
> On 10/09/2015 07:39 AM, Denis V. Lunev wrote:
> > From: Andrey Smetanin <asmetanin@virtuozzo.com>
> > 
> > A new vcpu exit is introduced to notify the userspace of the
> > changes in Hyper-V synic configuraion triggered by guest writing to the
> Again, is 'synic' intended?  Hmm, I see it throughout the patch, so it
> looks intentional, but I keep trying to read it as a typo for 'sync'.

I tend to mistype it as 'cynic' as better matching what it is ;)

Note taken, we'll address that in the next round, thanks.

Roman.