kvm/x86: Hyper-V synthetic interrupt controller
SynIC (synthetic interrupt controller) 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.
Changes v4:
* added activation of SynIC by vcpu KVM_ENABLE_CAP
* added per SynIC active flag
* added deactivation of APICv upon SynIC activation
Changes v3:
* added KVM_CAP_HYPERV_SYNIC and KVM_IRQ_ROUTING_HV_SINT notes into
docs
Changes v2:
* do not use posted interrupts for Hyper-V SynIC AutoEOI vectors
* add Hyper-V SynIC vectors into EOI exit bitmap
* Hyper-V SyniIC SINT msr write logic simplified
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: 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: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 62cf8c9..83a3c0c 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -23,13 +23,314 @@
#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_vector_connected(struct kvm_vcpu_hv_synic *synic,
+ int vector)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
+ if (synic_get_sint_vector(synic_read_sint(synic, i)) == vector)
+ return true;
+ }
+ return false;
+}
+
+static bool synic_has_vector_auto_eoi(struct kvm_vcpu_hv_synic *synic,
+ int vector)
+{
+ int i;
+ u64 sint_value;
+
+ for (i = 0; i < ARRAY_SIZE(synic->sint); i++) {
+ sint_value = synic_read_sint(synic, i);
+ if (synic_get_sint_vector(sint_value) == vector &&
+ sint_value & HV_SYNIC_SINT_AUTO_EOI)
+ 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 behavior. The bitmaps are
+ * updated here, and atomically queried on fast paths.
+ */
+
+ atomic64_set(&synic->sint[sint], data);
+
+ if (synic_has_vector_connected(synic, vector))
+ __set_bit(vector, synic->vec_bitmap);
+ else
+ __clear_bit(vector, synic->vec_bitmap);
+
+ if (synic_has_vector_auto_eoi(synic, vector))
+ __set_bit(vector, synic->auto_eoi_bitmap);
+ else
+ __clear_bit(vector, synic->auto_eoi_bitmap);
+
+ /* Load SynIC vectors into EOI exit bitmap */
+ kvm_make_request(KVM_REQ_SCAN_IOAPIC, synic_to_vcpu(synic));
+ return 0;
+}
+
+static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vcpu_id)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vcpu_hv_synic *synic;
+
+ if (vcpu_id >= atomic_read(&kvm->online_vcpus))
+ return NULL;
+ vcpu = kvm_get_vcpu(kvm, vcpu_id);
+ if (!vcpu)
+ return NULL;
+ synic = vcpu_to_synic(vcpu);
+ return (synic->active) ? synic : NULL;
+}
+
+static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint)
+{
+ struct kvm *kvm = vcpu->kvm;
+ int gsi, idx;
+
+ vcpu_debug(vcpu, "Hyper-V SynIC acked sint %d\n", sint);
+
+ idx = srcu_read_lock(&kvm->irq_srcu);
+ gsi = atomic_read(&vcpu_to_synic(vcpu)->sint_to_gsi[sint]);
+ if (gsi != -1)
+ kvm_notify_acked_gsi(kvm, gsi);
+ srcu_read_unlock(&kvm->irq_srcu, idx);
+}
+
+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;
+
+ if (!synic->active)
+ return 1;
+
+ vcpu_debug(vcpu, "Hyper-V SynIC 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_hv_notify_acked_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;
+
+ if (!synic->active)
+ return 1;
+
+ 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, "Hyper-V SynIC set irq ret %d\n", ret);
+ return ret;
+}
+
+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, "Hyper-V SynIC send 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_hv_notify_acked_sint(vcpu, i);
+}
+
+static 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;
+}
+
+void kvm_hv_irq_routing_update(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);
+ }
+ }
+}
+
+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));
+}
+
+int kvm_hv_activate_synic(struct kvm_vcpu *vcpu)
+{
+ /*
+ * Hyper-V SynIC auto EOI SINT's are
+ * not compatible with APICV, so deactivate APICV
+ */
+ kvm_vcpu_deactivate_apicv(vcpu);
+ vcpu_to_synic(vcpu)->active = true;
+ return 0;
+}
+
static bool kvm_hv_msr_partition_wide(u32 msr)
{
bool r = false;
@@ -226,6 +527,13 @@
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 +612,13 @@
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;