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Subject[PATCH v2 2/6] KVM: x86: decouple irqchip_in_kernel() and pic_irqchip()
Date
irqchip_in_kernel() tried to save a bit by reusing pic_irqchip(), but it
just complicated the code.
Add a separate state for the irqchip mode.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
v2: change two bools into one enum and rename everything [Paolo]
---
arch/x86/include/asm/kvm_host.h | 8 +++++++-
arch/x86/kvm/irq.h | 15 ++++++++-------
arch/x86/kvm/x86.c | 5 +++--
3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7892530cbacf..d3acd295446d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -715,6 +715,12 @@ struct kvm_hv {
HV_REFERENCE_TSC_PAGE tsc_ref;
};

+enum kvm_irqchip_mode {
+ KVM_IRQCHIP_NONE,
+ KVM_IRQCHIP_KERNEL, /* created with KVM_CREATE_IRQCHIP */
+ KVM_IRQCHIP_SPLIT, /* created with KVM_CAP_SPLIT_IRQCHIP */
+};
+
struct kvm_arch {
unsigned int n_used_mmu_pages;
unsigned int n_requested_mmu_pages;
@@ -787,7 +793,7 @@ struct kvm_arch {

u64 disabled_quirks;

- bool irqchip_split;
+ enum kvm_irqchip_mode irqchip_mode;
u8 nr_reserved_ioapic_pins;

bool disabled_lapic_found;
diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
index 035731eb3897..79cfc945125c 100644
--- a/arch/x86/kvm/irq.h
+++ b/arch/x86/kvm/irq.h
@@ -93,18 +93,19 @@ static inline int pic_in_kernel(struct kvm *kvm)

static inline int irqchip_split(struct kvm *kvm)
{
- return kvm->arch.irqchip_split;
+ return kvm->arch.irqchip_mode == KVM_IRQCHIP_SPLIT;
+}
+
+static inline int irqchip_kernel(struct kvm *kvm)
+{
+ return kvm->arch.irqchip_mode == KVM_IRQCHIP_KERNEL;
}

static inline int irqchip_in_kernel(struct kvm *kvm)
{
- struct kvm_pic *vpic = pic_irqchip(kvm);
- bool ret;
+ bool ret = irqchip_kernel(kvm) || irqchip_split(kvm);

- ret = (vpic != NULL);
- ret |= irqchip_split(kvm);
-
- /* Read vpic before kvm->irq_routing. */
+ /* Matches with wmb after initializing kvm->irq_routing. */
smp_rmb();
return ret;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e670591337af..a8dbfb4129c5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3872,7 +3872,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
goto split_irqchip_unlock;
/* Pairs with irqchip_in_kernel. */
smp_wmb();
- kvm->arch.irqchip_split = true;
+ kvm->arch.irqchip_mode = KVM_IRQCHIP_SPLIT;
kvm->arch.nr_reserved_ioapic_pins = cap->args[0];
r = 0;
split_irqchip_unlock:
@@ -3966,8 +3966,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
mutex_unlock(&kvm->slots_lock);
goto create_irqchip_unlock;
}
- /* Write kvm->irq_routing before kvm->arch.vpic. */
+ /* Write kvm->irq_routing before enabling irqchip_in_kernel. */
smp_wmb();
+ kvm->arch.irqchip_mode = KVM_IRQCHIP_KERNEL;
kvm->arch.vpic = vpic;
create_irqchip_unlock:
mutex_unlock(&kvm->lock);
--
2.11.0
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