diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt
index ab022dcd09117571d215294ed51c5675543165f1..97ca1940a0dc95645c05431017f1f06b7150905c 100644
--- a/Documentation/virtual/kvm/cpuid.txt
+++ b/Documentation/virtual/kvm/cpuid.txt
@@ -62,6 +62,10 @@ KVM_FEATURE_ASYNC_PF_VMEXIT || 10 || paravirtualized async PF VM exit
|| || can be enabled by setting bit 2
|| || when writing to msr 0x4b564d02
------------------------------------------------------------------------------
+KVM_FEATURE_PV_SEND_IPI || 11 || guest checks this feature bit
+ || || before using paravirtualized
+ || || send IPIs.
+------------------------------------------------------------------------------
KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side
|| || per-cpu warps are expected in
|| || kvmclock.
diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt
index a890529c63ed6a3be4e2c38eb739377b37c6bc4c..da24c138c8d131bea63aeb652af3d6fc373514ef 100644
--- a/Documentation/virtual/kvm/hypercalls.txt
+++ b/Documentation/virtual/kvm/hypercalls.txt
@@ -121,3 +121,23 @@ compute the CLOCK_REALTIME for its clock, at the same instant.
Returns KVM_EOPNOTSUPP if the host does not use TSC clocksource,
or if clock type is different than KVM_CLOCK_PAIRING_WALLCLOCK.
+
+6. KVM_HC_SEND_IPI
+------------------------
+Architecture: x86
+Status: active
+Purpose: Send IPIs to multiple vCPUs.
+
+a0: lower part of the bitmap of destination APIC IDs
+a1: higher part of the bitmap of destination APIC IDs
+a2: the lowest APIC ID in bitmap
+a3: APIC ICR
+
+The hypercall lets a guest send multicast IPIs, with at most 128
+128 destinations per hypercall in 64-bit mode and 64 vCPUs per
+hypercall in 32-bit mode. The destinations are represented by a
+bitmap contained in the first two arguments (a0 and a1). Bit 0 of
+a0 corresponds to the APIC ID in the third argument (a2), bit 1
+corresponds to the APIC ID a2+1, and so on.
+
+Returns the number of CPUs to which the IPIs were delivered successfully.
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 150937e64f6372d2b209f2384d391c399547ffed..c18958ef17d2cdc4ccfc6ac80a4752198bded1b6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1457,6 +1457,10 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu);
+int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low,
+ unsigned long ipi_bitmap_high, int min,
+ unsigned long icr, int op_64_bit);
+
void kvm_define_shared_msr(unsigned index, u32 msr);
int kvm_set_shared_msr(unsigned index, u64 val, u64 mask);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7e042e3d47fd5a007cd70ad20d2f5d6ee525c28e..7bcfa61375c097fa71e0d6b168f8493c8a9f4ad9 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -621,7 +621,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
(1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
(1 << KVM_FEATURE_PV_UNHALT) |
(1 << KVM_FEATURE_PV_TLB_FLUSH) |
- (1 << KVM_FEATURE_ASYNC_PF_VMEXIT);
+ (1 << KVM_FEATURE_ASYNC_PF_VMEXIT) |
+ (1 << KVM_FEATURE_PV_SEND_IPI);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b5cd8465d44f6cb99a9ae705cf2f44f3c310a1ac..f0d693122c24898b3525e384492b335fbf2cfe11 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -547,6 +547,46 @@ int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
irq->level, irq->trig_mode, dest_map);
}
+int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low,
+ unsigned long ipi_bitmap_high, int min,
+ unsigned long icr, int op_64_bit)
+{
+ int i;
+ struct kvm_apic_map *map;
+ struct kvm_vcpu *vcpu;
+ struct kvm_lapic_irq irq = {0};
+ int cluster_size = op_64_bit ? 64 : 32;
+ int count = 0;
+
+ irq.vector = icr & APIC_VECTOR_MASK;
+ irq.delivery_mode = icr & APIC_MODE_MASK;
+ irq.level = (icr & APIC_INT_ASSERT) != 0;
+ irq.trig_mode = icr & APIC_INT_LEVELTRIG;
+
+ if (icr & APIC_DEST_MASK)
+ return -KVM_EINVAL;
+ if (icr & APIC_SHORT_MASK)
+ return -KVM_EINVAL;
+
+ rcu_read_lock();
+ map = rcu_dereference(kvm->arch.apic_map);
+
+ /* Bits above cluster_size are masked in the caller. */
+ for_each_set_bit(i, &ipi_bitmap_low, BITS_PER_LONG) {
+ vcpu = map->phys_map[min + i]->vcpu;
+ count += kvm_apic_set_irq(vcpu, &irq, NULL);
+ }
+
+ min += cluster_size;
+ for_each_set_bit(i, &ipi_bitmap_high, BITS_PER_LONG) {
+ vcpu = map->phys_map[min + i]->vcpu;
+ count += kvm_apic_set_irq(vcpu, &irq, NULL);
+ }
+
+ rcu_read_unlock();
+ return count;
+}
+
static int pv_eoi_put_user(struct kvm_vcpu *vcpu, u8 val)
{
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6b974802cadbafd89818ef67b69f30715006f7d8..3c83711c0ebe147e4251db1c3a30ea1799d5042f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6802,6 +6802,9 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
case KVM_HC_CLOCK_PAIRING:
ret = kvm_pv_clock_pairing(vcpu, a0, a1);
break;
+ case KVM_HC_SEND_IPI:
+ ret = kvm_pv_send_ipi(vcpu->kvm, a0, a1, a2, a3, op_64_bit);
+ break;
#endif
default:
ret = -KVM_ENOSYS;
diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h
index dcf629dd28896b2010f3fcd4fc8516130a71e80a..f3893ef82b653a259e6450526e26d0a3309e513e 100644
--- a/include/uapi/linux/kvm_para.h
+++ b/include/uapi/linux/kvm_para.h
@@ -13,6 +13,7 @@
/* Return values for hypercalls */
#define KVM_ENOSYS 1000
#define KVM_EFAULT EFAULT
+#define KVM_EINVAL EINVAL
#define KVM_E2BIG E2BIG
#define KVM_EPERM EPERM
#define KVM_EOPNOTSUPP 95