On 23/07/2018 08:39, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>
> Fallback to original apic hooks when unlikely kvm fails to add the
> pending IRQ to lapic.
>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> ---
> arch/x86/kernel/kvm.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index eed6046..57eb4a2 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)
> @@ -454,10 +455,10 @@ static void __init sev_map_percpu_data(void)
> }
>
> #ifdef CONFIG_SMP
> -static void __send_ipi_mask(const struct cpumask *mask, int vector)
> +static int __send_ipi_mask(const struct cpumask *mask, int vector)
> {
> unsigned long flags;
> - int cpu, apic_id, min = 0, max = 0;
> + int cpu, apic_id, min = 0, max = 0, ret = 0;
> #ifdef CONFIG_X86_64
> __uint128_t ipi_bitmap = 0;
> int cluster_size = 128;
> @@ -467,7 +468,7 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
> #endif
>
> if (cpumask_empty(mask))
> - return;
> + return 0;
>
> local_irq_save(flags);
>
> @@ -481,7 +482,7 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
> } else if (apic_id < min + cluster_size) {
> max = apic_id < max ? max : apic_id;
> } else {
> - kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
> + ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
> (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, vector);
> min = max = apic_id;
> ipi_bitmap = 0;
> @@ -490,11 +491,12 @@ static void __send_ipi_mask(const struct cpumask *mask, int vector)
> }
>
> if (ipi_bitmap) {
> - kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
> + ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
> (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, vector);
> }
>
> local_irq_restore(flags);
> + return ret;
> }
>
> static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
> @@ -511,7 +513,8 @@ static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
> cpumask_copy(&new_mask, mask);
> cpumask_clear_cpu(this_cpu, &new_mask);
> local_mask = &new_mask;
> - __send_ipi_mask(local_mask, vector);
> + if (__send_ipi_mask(local_mask, vector))
> + orig_apic.send_IPI_mask_allbutself(mask, vector);
> }
>
> static void kvm_send_ipi_allbutself(int vector)
> @@ -521,7 +524,8 @@ static void kvm_send_ipi_allbutself(int vector)
>
> static void kvm_send_ipi_all(int vector)
> {
> - __send_ipi_mask(cpu_online_mask, vector);
> + if (__send_ipi_mask(cpu_online_mask, vector))
> + orig_apic.send_IPI_all(vector);
> }
>
> /*
> @@ -529,6 +533,8 @@ static void kvm_send_ipi_all(int vector)
> */
> 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;
>
Is this actually needed?
Paolo
