On Tue, Feb 26, 2013 at 08:34:16PM +0800, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>
> In the platform which supporing virtual interrupt delivery feature,
> hardware will clear vIRR atomatically when target vcpu is running.
> So software should not modify vIRR when target vcpu is running. This
> patch will record the virtual interrupt into posted_irr when delivering
> virtual interrupt to guest. And then sync posted_irr into vIRR in target
> vcpu context.
>
> The patch to enable Posted Interrupt has the similar logic. Since we are
> still discussing it, so split this part from Posted Interrupt patch to
> fix the virtual interrupt delivery issue.
>
What the point of having this over posted interrupt patches considering
that PI patches do this and more?
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
> ---
> arch/x86/kvm/lapic.c | 39 ++++++++++++++++++++++++++++++++++++++-
> arch/x86/kvm/lapic.h | 3 +++
> arch/x86/kvm/vmx.c | 3 ++-
> 3 files changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 02b51dd..98bc37e 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -357,6 +357,11 @@ static u8 count_vectors(void *bitmap)
> return count;
> }
>
> +static inline bool apic_test_irr(int vec, struct kvm_lapic *apic)
> +{
> + return apic_test_vector(vec, apic->regs + APIC_IRR);
> +}
> +
> static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
> {
> apic->irr_pending = true;
> @@ -368,6 +373,26 @@ static inline int apic_search_irr(struct kvm_lapic *apic)
> return find_highest_vector(apic->regs + APIC_IRR);
> }
>
> +static inline void kvm_apic_update_irr(struct kvm_lapic *apic)
> +{
> + int index;
> +
> + if (!kvm_x86_ops->vm_has_apicv(apic->vcpu->kvm))
> + return;
> +
> + if (apic->posted_irr_changed) {
> + spin_lock(&apic->posted_irr_lock);
> + for_each_set_bit(index,
> + (unsigned long *)(&apic->posted_irr_changed), 8) {
> + *((u32 *)(apic->regs + APIC_IRR + index * 0x10)) |=
> + apic->posted_irr[index];
> + apic->posted_irr[index] = 0;
> + }
> + apic->posted_irr_changed = 0;
> + spin_unlock(&apic->posted_irr_lock);
> + }
> +}
> +
> static inline int apic_find_highest_irr(struct kvm_lapic *apic)
> {
> int result;
> @@ -379,6 +404,7 @@ static inline int apic_find_highest_irr(struct kvm_lapic *apic)
> if (!apic->irr_pending)
> return -1;
>
> + kvm_apic_update_irr(apic);
> result = apic_search_irr(apic);
> ASSERT(result == -1 || result >= 16);
>
> @@ -700,7 +726,17 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
> } else
> apic_clear_vector(vector, apic->regs + APIC_TMR);
>
> - result = !apic_test_and_set_irr(vector, apic);
> + if (kvm_x86_ops->vm_has_apicv(vcpu->kvm)) {
> + spin_lock(&apic->posted_irr_lock);
> + if (!apic_test_irr(vector, apic))
> + result = !test_and_set_bit(vector,
> + (unsigned long *)apic->posted_irr);
> + if (result)
> + apic->posted_irr_changed |= 1 << (vector >> 5);
> + spin_unlock(&apic->posted_irr_lock);
> + } else {
> + result = !apic_test_and_set_irr(vector, apic);
> + }
> trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
> trig_mode, vector, !result);
> if (!result) {
> @@ -1567,6 +1603,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
> static_key_slow_inc(&apic_sw_disabled.key); /* sw disabled at reset */
> kvm_lapic_reset(vcpu);
> kvm_iodevice_init(&apic->dev, &apic_mmio_ops);
> + spin_lock_init(&apic->posted_irr_lock);
>
> return 0;
> nomem_free_apic:
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index 1676d34..38bebc8 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -20,6 +20,9 @@ struct kvm_lapic {
> u32 divide_count;
> struct kvm_vcpu *vcpu;
> bool irr_pending;
> + u32 posted_irr[8];
> + u8 posted_irr_changed;
> + spinlock_t posted_irr_lock;
> /* Number of bits set in ISR. */
> s16 isr_count;
> /* The highest vector set in ISR; if -1 - invalid, must scan ISR. */
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index c1b3041..c8e6036 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -84,7 +84,8 @@ module_param(vmm_exclusive, bool, S_IRUGO);
> static bool __read_mostly fasteoi = 1;
> module_param(fasteoi, bool, S_IRUGO);
>
> -static bool __read_mostly enable_apicv_reg_vid;
> +static bool __read_mostly enable_apicv_reg_vid = 1;
> +module_param(enable_apicv_reg_vid, bool, S_IRUGO);
>
> /*
> * If nested=1, nested virtualization is supported, i.e., guests may use
> --
> 1.7.1
--
Gleb.
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