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Subject[PATCH v3 02/16] kvm: x86: Introduce KVM APICv state
Date
Currently, after a VM boots with APICv enabled, it could go into
the following states:

* activated = VM is running w/ APICv
* suspended = VM deactivate APICv temporarily
* disabled = VM deactivate APICv permanently

Introduce KVM APICv state enum to help keep track of the APICv states
along with a new variable struct kvm_arch.apicv_state to store
the current state of each VM, and kvm_arch.apicv_lock to synchronize
access of apicv_state since it can be accessed by each vcpu.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
arch/x86/include/asm/kvm_host.h | 11 +++++++++++
arch/x86/kvm/x86.c | 14 +++++++++++++-
2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 277f06f..562bfbd 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -851,6 +851,15 @@ enum kvm_irqchip_mode {
KVM_IRQCHIP_SPLIT, /* created with KVM_CAP_SPLIT_IRQCHIP */
};

+/*
+ * KVM assumes all vcpus in a VM operate in the same mode.
+ */
+enum kvm_apicv_state {
+ APICV_DISABLED, /* Disabled (such as for Hyper-V case) */
+ APICV_SUSPENDED, /* Deactivated temporary */
+ APICV_ACTIVATED, /* Default status when APICV is enabled */
+};
+
struct kvm_arch {
unsigned long n_used_mmu_pages;
unsigned long n_requested_mmu_pages;
@@ -879,6 +888,8 @@ struct kvm_arch {
struct kvm_apic_map *apic_map;

bool apic_access_page_done;
+ struct mutex apicv_lock;
+ enum kvm_apicv_state apicv_state;

gpa_t wall_clock;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 01f5a56..64d275e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4630,6 +4630,8 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
kvm->arch.irqchip_mode = KVM_IRQCHIP_SPLIT;
kvm->arch.nr_reserved_ioapic_pins = cap->args[0];
r = 0;
+ if (kvm_x86_ops->get_enable_apicv(kvm))
+ kvm->arch.apicv_state = APICV_ACTIVATED;
split_irqchip_unlock:
mutex_unlock(&kvm->lock);
break;
@@ -4749,6 +4751,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
/* Write kvm->irq_routing before enabling irqchip_in_kernel. */
smp_wmb();
kvm->arch.irqchip_mode = KVM_IRQCHIP_KERNEL;
+ if (kvm_x86_ops->get_enable_apicv(kvm))
+ kvm->arch.apicv_state = APICV_ACTIVATED;
create_irqchip_unlock:
mutex_unlock(&kvm->lock);
break;
@@ -9209,13 +9213,18 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
goto fail_free_pio_data;

if (irqchip_in_kernel(vcpu->kvm)) {
- vcpu->arch.apicv_active = kvm_x86_ops->get_enable_apicv(vcpu->kvm);
r = kvm_create_lapic(vcpu, lapic_timer_advance_ns);
if (r < 0)
goto fail_mmu_destroy;
} else
static_key_slow_inc(&kvm_no_apic_vcpu);

+ mutex_lock(&vcpu->kvm->arch.apicv_lock);
+ if (irqchip_in_kernel(vcpu->kvm) &&
+ vcpu->kvm->arch.apicv_state == APICV_ACTIVATED)
+ vcpu->arch.apicv_active = kvm_x86_ops->get_enable_apicv(vcpu->kvm);
+ mutex_unlock(&vcpu->kvm->arch.apicv_lock);
+
vcpu->arch.mce_banks = kzalloc(KVM_MAX_MCE_BANKS * sizeof(u64) * 4,
GFP_KERNEL_ACCOUNT);
if (!vcpu->arch.mce_banks) {
@@ -9314,6 +9323,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
kvm_page_track_init(kvm);
kvm_mmu_init_vm(kvm);

+ /* APICV initialization */
+ mutex_init(&kvm->arch.apicv_lock);
+
if (kvm_x86_ops->vm_init)
return kvm_x86_ops->vm_init(kvm);

--
1.8.3.1
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