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Subject[PATCH 1/2] KVM: X86: Implement PV IPI in linux guest
Date
From: Wanpeng Li <wanpengli@tencent.com>

Implement PV IPIs in guest kernel.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/include/uapi/asm/kvm_para.h | 1 +
arch/x86/kernel/kvm.c | 63 ++++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)

diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 0ede697..19980ec 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -28,6 +28,7 @@
#define KVM_FEATURE_PV_UNHALT 7
#define KVM_FEATURE_PV_TLB_FLUSH 9
#define KVM_FEATURE_ASYNC_PF_VMEXIT 10
+#define KVM_FEATURE_PV_SEND_IPI 11

#define KVM_HINTS_REALTIME 0

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5b2300b..b4f8dc3 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -454,6 +454,57 @@ static void __init sev_map_percpu_data(void)
}

#ifdef CONFIG_SMP
+
+static void __send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ unsigned long flags, ipi_bitmap = 0;
+ int cpu;
+
+ local_irq_save(flags);
+
+ for_each_cpu(cpu, mask)
+ __set_bit(per_cpu(x86_cpu_to_apicid, cpu), &ipi_bitmap);
+ kvm_hypercall2(KVM_HC_SEND_IPI, ipi_bitmap, vector);
+
+ local_irq_restore(flags);
+}
+
+static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ __send_ipi_mask(mask, vector);
+}
+
+static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
+{
+ unsigned int this_cpu = smp_processor_id();
+ struct cpumask new_mask;
+ const struct cpumask *local_mask;
+
+ cpumask_copy(&new_mask, mask);
+ cpumask_clear_cpu(this_cpu, &new_mask);
+ local_mask = &new_mask;
+ __send_ipi_mask(local_mask, vector);
+}
+
+static void kvm_send_ipi_allbutself(int vector)
+{
+ kvm_send_ipi_mask_allbutself(cpu_online_mask, vector);
+}
+
+static void kvm_send_ipi_all(int vector)
+{
+ __send_ipi_mask(cpu_online_mask, vector);
+}
+
+static void kvm_setup_pv_ipi(void)
+{
+ apic->send_IPI_mask = kvm_send_ipi_mask;
+ apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+ apic->send_IPI_allbutself = kvm_send_ipi_allbutself;
+ apic->send_IPI_all = kvm_send_ipi_all;
+ printk("KVM setup pv IPIs\n");
+}
+
static void __init kvm_smp_prepare_cpus(unsigned int max_cpus)
{
native_smp_prepare_cpus(max_cpus);
@@ -624,12 +675,24 @@ static uint32_t __init kvm_detect(void)
return kvm_cpuid_base();
}

+static void __init kvm_apic_init(void)
+{
+ if (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI))
+ kvm_setup_pv_ipi();
+}
+
+static void __init kvm_init_platform(void)
+{
+ x86_platform.apic_post_init = kvm_apic_init;
+}
+
const __initconst struct hypervisor_x86 x86_hyper_kvm = {
.name = "KVM",
.detect = kvm_detect,
.type = X86_HYPER_KVM,
.init.guest_late_init = kvm_guest_init,
.init.x2apic_available = kvm_para_available,
+ .init.init_platform = kvm_init_platform,
};

static __init int activate_jump_labels(void)
--
2.7.4
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