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Date: Mon, 2 Jul 2018 18:14:21 +0800
From: Wanpeng Li <kernellwp@...il.com>
To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>,
Radim Krčmář <rkrcmar@...hat.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>
Subject: [PATCH v2 1/2] KVM: X86: Implement PV IPI in linux guest
From: Wanpeng Li <wanpengli@...cent.com>
Implement PV IPIs in guest kernel.
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
---
arch/x86/kernel/kvm.c | 99 +++++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/kvm_para.h | 1 +
2 files changed, 100 insertions(+)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5b2300b..7e3ee25 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -47,6 +47,7 @@
#include <asm/hypervisor.h>
#include <asm/kvm_guest.h>
+static struct apic orig_apic;
static int kvmapf = 1;
static int __init parse_no_kvmapf(char *arg)
@@ -454,6 +455,89 @@ static void __init sev_map_percpu_data(void)
}
#ifdef CONFIG_SMP
+
+#ifdef CONFIG_X86_64
+static bool __send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ unsigned long flags, ipi_bitmap_low = 0, ipi_bitmap_high = 0, icr = 0;
+ int cpu, apic_id, ret = 1;
+
+ if (cpumask_empty(mask))
+ return true;
+
+ local_irq_save(flags);
+
+ for_each_cpu(cpu, mask) {
+ apic_id = per_cpu(x86_cpu_to_apicid, cpu);
+ if (apic_id < BITS_PER_LONG)
+ __set_bit(apic_id, &ipi_bitmap_low);
+ else if (apic_id < 2 * BITS_PER_LONG)
+ __set_bit(apic_id - BITS_PER_LONG, &ipi_bitmap_high);
+ else
+ goto ipi_mask_done;
+ }
+
+ switch (vector) {
+ default:
+ icr = APIC_DM_FIXED | vector;
+ break;
+ case NMI_VECTOR:
+ icr = APIC_DM_NMI;
+ break;
+ }
+
+ ret = kvm_hypercall3(KVM_HC_SEND_IPI, ipi_bitmap_low, ipi_bitmap_high, icr);
+
+ipi_mask_done:
+ local_irq_restore(flags);
+ return ((ret == 0) ? true : false);
+}
+
+static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ if (!__send_ipi_mask(mask, vector))
+ orig_apic.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;
+ if (!__send_ipi_mask(local_mask, vector))
+ orig_apic.send_IPI_mask_allbutself(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)
+{
+ if (!__send_ipi_mask(cpu_online_mask, vector))
+ orig_apic.send_IPI_all(vector);
+}
+
+/*
+ * Set the IPI entry points
+ */
+static void kvm_setup_pv_ipi(void)
+{
+ orig_apic = *apic;
+
+ 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;
+ pr_info("KVM setup pv IPIs\n");
+}
+#endif
+
static void __init kvm_smp_prepare_cpus(unsigned int max_cpus)
{
native_smp_prepare_cpus(max_cpus);
@@ -624,12 +708,27 @@ static uint32_t __init kvm_detect(void)
return kvm_cpuid_base();
}
+static void __init kvm_apic_init(void)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_64)
+ if (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI) &&
+ num_possible_cpus() <= 2 * BITS_PER_LONG)
+ kvm_setup_pv_ipi();
+#endif
+}
+
+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)
diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h
index dcf629d..7395f38 100644
--- a/include/uapi/linux/kvm_para.h
+++ b/include/uapi/linux/kvm_para.h
@@ -26,6 +26,7 @@
#define KVM_HC_MIPS_EXIT_VM 7
#define KVM_HC_MIPS_CONSOLE_OUTPUT 8
#define KVM_HC_CLOCK_PAIRING 9
+#define KVM_HC_SEND_IPI 10
/*
* hypercalls use architecture specific
--
2.7.4
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