From 49df6397edfc5a8ba8ca813b51fb9729d8e94b40 Mon Sep 17 00:00:00 2001 From: Steve Rutherford Date: Wed, 29 Jul 2015 23:21:40 -0700 Subject: [PATCH] KVM: x86: Split the APIC from the rest of IRQCHIP. First patch in a series which enables the relocation of the PIC/IOAPIC to userspace. Adds capability KVM_CAP_SPLIT_IRQCHIP; KVM_CAP_SPLIT_IRQCHIP enables the construction of LAPICs without the rest of the irqchip. Compile tested for x86. Signed-off-by: Steve Rutherford Suggested-by: Andrew Honig Signed-off-by: Paolo Bonzini --- Documentation/virtual/kvm/api.txt | 17 +++++++++++++++++ arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/i8254.c | 4 +++- arch/x86/kvm/ioapic.h | 8 ++++++++ arch/x86/kvm/irq.h | 11 ++++++++++- arch/x86/kvm/irq_comm.c | 9 ++++++++- arch/x86/kvm/lapic.c | 6 ++++-- arch/x86/kvm/x86.c | 23 +++++++++++++++++++++-- include/linux/kvm_host.h | 1 + include/uapi/linux/kvm.h | 1 + 10 files changed, 75 insertions(+), 7 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index d9ecceea5a02..43e0816d0de1 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -3627,6 +3627,23 @@ struct { KVM handlers should exit to userspace with rc = -EREMOTE. +7.5 KVM_CAP_SPLIT_IRQCHIP + +Architectures: x86 +Parameters: None +Returns: 0 on success, -1 on error + +Create a local apic for each processor in the kernel. This can be used +instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the +IOAPIC and PIC (and also the PIT, even though this has to be enabled +separately). + +This supersedes KVM_CREATE_IRQCHIP, creating only local APICs, but no in kernel +IOAPIC or PIC. This also enables in kernel routing of interrupt requests. + +Fails if VCPU has already been created, or if the irqchip is already in the +kernel (i.e. KVM_CREATE_IRQCHIP has already been called). + 8. Other capabilities. ---------------------- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index a0ef289d5a86..befcf555bddc 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -684,6 +684,8 @@ struct kvm_arch { u32 bsp_vcpu_id; u64 disabled_quirks; + + bool irqchip_split; }; struct kvm_vm_stat { diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index f90952f64e79..08116ff227cc 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -35,6 +35,7 @@ #include #include +#include "ioapic.h" #include "irq.h" #include "i8254.h" #include "x86.h" @@ -333,7 +334,8 @@ static void create_pit_timer(struct kvm *kvm, u32 val, int is_period) struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state; s64 interval; - if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY) + if (!ioapic_in_kernel(kvm) || + ps->flags & KVM_PIT_FLAGS_HPET_LEGACY) return; interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ); diff --git a/arch/x86/kvm/ioapic.h b/arch/x86/kvm/ioapic.h index bf36d66a1951..a8842c0dee73 100644 --- a/arch/x86/kvm/ioapic.h +++ b/arch/x86/kvm/ioapic.h @@ -97,6 +97,14 @@ static inline struct kvm_ioapic *ioapic_irqchip(struct kvm *kvm) return kvm->arch.vioapic; } +static inline int ioapic_in_kernel(struct kvm *kvm) +{ + int ret; + + ret = (ioapic_irqchip(kvm) != NULL); + return ret; +} + void kvm_rtc_eoi_tracking_restore_one(struct kvm_vcpu *vcpu); bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source, int short_hand, unsigned int dest, int dest_mode); diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h index 9e6e7e04de98..2f9703dcd913 100644 --- a/arch/x86/kvm/irq.h +++ b/arch/x86/kvm/irq.h @@ -83,13 +83,22 @@ static inline struct kvm_pic *pic_irqchip(struct kvm *kvm) return kvm->arch.vpic; } +static inline int irqchip_split(struct kvm *kvm) +{ + return kvm->arch.irqchip_split; +} + static inline int irqchip_in_kernel(struct kvm *kvm) { struct kvm_pic *vpic = pic_irqchip(kvm); + bool ret; + + ret = (vpic != NULL); + ret |= irqchip_split(kvm); /* Read vpic before kvm->irq_routing. */ smp_rmb(); - return vpic != NULL; + return ret; } static inline int lapic_in_kernel(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c index 9efff9e5b58c..67f6b62a6814 100644 --- a/arch/x86/kvm/irq_comm.c +++ b/arch/x86/kvm/irq_comm.c @@ -208,7 +208,7 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id) goto unlock; } clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap); - if (!irqchip_in_kernel(kvm)) + if (!ioapic_in_kernel(kvm)) goto unlock; kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id); @@ -328,3 +328,10 @@ int kvm_setup_default_irq_routing(struct kvm *kvm) return kvm_set_irq_routing(kvm, default_routing, ARRAY_SIZE(default_routing), 0); } + +static const struct kvm_irq_routing_entry empty_routing[] = {}; + +int kvm_setup_empty_irq_routing(struct kvm *kvm) +{ + return kvm_set_irq_routing(kvm, empty_routing, 0, 0); +} diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index c4bcc86d6dc4..e05946c36b87 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -209,7 +209,8 @@ out: if (old) kfree_rcu(old, rcu); - kvm_vcpu_request_scan_ioapic(kvm); + if (ioapic_in_kernel(kvm)) + kvm_vcpu_request_scan_ioapic(kvm); } static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val) @@ -1845,7 +1846,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu, kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic)); kvm_make_request(KVM_REQ_EVENT, vcpu); - kvm_rtc_eoi_tracking_restore_one(vcpu); + if (ioapic_in_kernel(vcpu->kvm)) + kvm_rtc_eoi_tracking_restore_one(vcpu); } void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 28c98c8f9d1c..f720774a4797 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2448,6 +2448,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ENABLE_CAP_VM: case KVM_CAP_DISABLE_QUIRKS: case KVM_CAP_SET_BOOT_CPU_ID: + case KVM_CAP_SPLIT_IRQCHIP: #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT case KVM_CAP_ASSIGN_DEV_IRQ: case KVM_CAP_PCI_2_3: @@ -3555,6 +3556,24 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, kvm->arch.disabled_quirks = cap->args[0]; r = 0; break; + case KVM_CAP_SPLIT_IRQCHIP: { + mutex_lock(&kvm->lock); + r = -EEXIST; + if (irqchip_in_kernel(kvm)) + goto split_irqchip_unlock; + if (atomic_read(&kvm->online_vcpus)) + goto split_irqchip_unlock; + r = kvm_setup_empty_irq_routing(kvm); + if (r) + goto split_irqchip_unlock; + /* Pairs with irqchip_in_kernel. */ + smp_wmb(); + kvm->arch.irqchip_split = true; + r = 0; +split_irqchip_unlock: + mutex_unlock(&kvm->lock); + break; + } default: r = -EINVAL; break; @@ -3668,7 +3687,7 @@ long kvm_arch_vm_ioctl(struct file *filp, } r = -ENXIO; - if (!irqchip_in_kernel(kvm)) + if (!irqchip_in_kernel(kvm) || irqchip_split(kvm)) goto get_irqchip_out; r = kvm_vm_ioctl_get_irqchip(kvm, chip); if (r) @@ -3692,7 +3711,7 @@ long kvm_arch_vm_ioctl(struct file *filp, } r = -ENXIO; - if (!irqchip_in_kernel(kvm)) + if (!irqchip_in_kernel(kvm) || irqchip_split(kvm)) goto set_irqchip_out; r = kvm_vm_ioctl_set_irqchip(kvm, chip); if (r) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 1bef9e21e725..354f147647ab 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1002,6 +1002,7 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq) #endif int kvm_setup_default_irq_routing(struct kvm *kvm); +int kvm_setup_empty_irq_routing(struct kvm *kvm); int kvm_set_irq_routing(struct kvm *kvm, const struct kvm_irq_routing_entry *entries, unsigned nr, diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a9256f0331ae..ed00f8fc9ea2 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -824,6 +824,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_MULTI_ADDRESS_SPACE 118 #define KVM_CAP_GUEST_DEBUG_HW_BPS 119 #define KVM_CAP_GUEST_DEBUG_HW_WPS 120 +#define KVM_CAP_SPLIT_IRQCHIP 121 #ifdef KVM_CAP_IRQ_ROUTING