RE: [v3 21/26] x86, irq: Define a global vector for VT-d Posted-Interrupts

["Zhang, Yang Z" <yang.z.zhang@intel.com>]

Feng Wu wrote on 2014-12-12:
> Currently, we use a global vector as the Posted-Interrupts
> Notification Event for all the vCPUs in the system. We need to
> introduce another global vector for VT-d Posted-Interrtups, which will
> be used to wakeup the sleep vCPU when an external interrupt from a direct-assigned device happens for that vCPU.
> 

Hi Feng, 

Since the idea of two global vectors mechanism is from me, please add me to the comments.

> Signed-off-by: Feng Wu <feng.wu@intel.com>
> ---
>  arch/x86/include/asm/entry_arch.h  |  2 ++
>  arch/x86/include/asm/hardirq.h     |  1 +
>  arch/x86/include/asm/hw_irq.h      |  2 ++
>  arch/x86/include/asm/irq_vectors.h |  1 +
>  arch/x86/kernel/entry_64.S         |  2 ++
>  arch/x86/kernel/irq.c              | 27 +++++++++++++++++++++++++++
>  arch/x86/kernel/irqinit.c          |  2 ++
>  7 files changed, 37 insertions(+)
> diff --git a/arch/x86/include/asm/entry_arch.h
> b/arch/x86/include/asm/entry_arch.h index dc5fa66..27ca0af 100644 ---
> a/arch/x86/include/asm/entry_arch.h +++
> b/arch/x86/include/asm/entry_arch.h @@ -23,6 +23,8 @@
> BUILD_INTERRUPT(x86_platform_ipi, X86_PLATFORM_IPI_VECTOR)  #ifdef
> CONFIG_HAVE_KVM BUILD_INTERRUPT3(kvm_posted_intr_ipi, POSTED_INTR_VECTOR,
>  		 smp_kvm_posted_intr_ipi)
> +BUILD_INTERRUPT3(kvm_posted_intr_wakeup_ipi, POSTED_INTR_WAKEUP_VECTOR,
> +		 smp_kvm_posted_intr_wakeup_ipi)
>  #endif
>  
>  /*
> diff --git a/arch/x86/include/asm/hardirq.h
> b/arch/x86/include/asm/hardirq.h index 0f5fb6b..9866065 100644
> --- a/arch/x86/include/asm/hardirq.h
> +++ b/arch/x86/include/asm/hardirq.h
> @@ -14,6 +14,7 @@ typedef struct {
>  #endif #ifdef CONFIG_HAVE_KVM 	unsigned int kvm_posted_intr_ipis;
>  +	unsigned int kvm_posted_intr_wakeup_ipis; #endif 	unsigned int
>  x86_platform_ipis;	/* arch dependent */ 	unsigned int apic_perf_irqs;
> diff --git a/arch/x86/include/asm/hw_irq.h
> b/arch/x86/include/asm/hw_irq.h index e7ae6eb..38fac9b 100644
> --- a/arch/x86/include/asm/hw_irq.h
> +++ b/arch/x86/include/asm/hw_irq.h
> @@ -29,6 +29,7 @@
>  extern asmlinkage void apic_timer_interrupt(void);  extern asmlinkage
> void x86_platform_ipi(void);  extern asmlinkage void
> kvm_posted_intr_ipi(void); +extern asmlinkage void
> kvm_posted_intr_wakeup_ipi(void);
>  extern asmlinkage void error_interrupt(void);  extern asmlinkage void
> irq_work_interrupt(void);
> 
> @@ -92,6 +93,7 @@ extern void
> trace_call_function_single_interrupt(void);
>  #define trace_irq_move_cleanup_interrupt  irq_move_cleanup_interrupt
> #define trace_reboot_interrupt  reboot_interrupt  #define
> trace_kvm_posted_intr_ipi kvm_posted_intr_ipi
> +#define trace_kvm_posted_intr_wakeup_ipi kvm_posted_intr_wakeup_ipi
>  #endif /* CONFIG_TRACING */
>  
>  struct irq_domain;
> diff --git a/arch/x86/include/asm/irq_vectors.h
> b/arch/x86/include/asm/irq_vectors.h index b26cb12..dca94f2 100644 ---
> a/arch/x86/include/asm/irq_vectors.h +++
> b/arch/x86/include/asm/irq_vectors.h @@ -105,6 +105,7 @@
>  /* Vector for KVM to deliver posted interrupt IPI */  #ifdef
>  CONFIG_HAVE_KVM #define POSTED_INTR_VECTOR		0xf2 +#define
>  POSTED_INTR_WAKEUP_VECTOR	0xf1 #endif
>  
>  /*
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index e61c14a..a598447 100644 --- a/arch/x86/kernel/entry_64.S +++
> b/arch/x86/kernel/entry_64.S @@ -960,6 +960,8 @@ apicinterrupt
> X86_PLATFORM_IPI_VECTOR \  #ifdef CONFIG_HAVE_KVM
>  apicinterrupt3 POSTED_INTR_VECTOR \
>  	kvm_posted_intr_ipi smp_kvm_posted_intr_ipi
> +apicinterrupt3 POSTED_INTR_WAKEUP_VECTOR \
> +	kvm_posted_intr_wakeup_ipi smp_kvm_posted_intr_wakeup_ipi
>  #endif
>  
>  #ifdef CONFIG_X86_MCE_THRESHOLD
> diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index
> 922d285..47408c3 100644
> --- a/arch/x86/kernel/irq.c
> +++ b/arch/x86/kernel/irq.c
> @@ -237,6 +237,9 @@ __visible void smp_x86_platform_ipi(struct pt_regs
> *regs)  }
> 
>  #ifdef CONFIG_HAVE_KVM
> +void (*wakeup_handler_callback)(void) = NULL;
> +EXPORT_SYMBOL_GPL(wakeup_handler_callback); +
>  /*
>   * Handler for POSTED_INTERRUPT_VECTOR.
>   */
> @@ -256,6 +259,30 @@ __visible void smp_kvm_posted_intr_ipi(struct
> pt_regs *regs)
> 
>  	set_irq_regs(old_regs);
>  }
> +
> +/*
> + * Handler for POSTED_INTERRUPT_WAKEUP_VECTOR.
> + */
> +__visible void smp_kvm_posted_intr_wakeup_ipi(struct pt_regs *regs) {
> +	struct pt_regs *old_regs = set_irq_regs(regs);
> +
> +	ack_APIC_irq();
> +
> +	irq_enter();
> +
> +	exit_idle();
> +
> +	inc_irq_stat(kvm_posted_intr_wakeup_ipis);
> +
> +	if (wakeup_handler_callback)
> +		wakeup_handler_callback();
> +
> +	irq_exit();
> +
> +	set_irq_regs(old_regs);
> +}
> +
>  #endif
>  
>  __visible void smp_trace_x86_platform_ipi(struct pt_regs *regs) diff
> --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c index
> 70e181e..844673c 100644 --- a/arch/x86/kernel/irqinit.c +++
> b/arch/x86/kernel/irqinit.c @@ -144,6 +144,8 @@ static void __init
> apic_intr_init(void)  #ifdef CONFIG_HAVE_KVM
>  	/* IPI for KVM to deliver posted interrupt */
>  	alloc_intr_gate(POSTED_INTR_VECTOR, kvm_posted_intr_ipi);
> +	/* IPI for KVM to deliver interrupt to wake up tasks */
> +	alloc_intr_gate(POSTED_INTR_WAKEUP_VECTOR,
> +kvm_posted_intr_wakeup_ipi);
>  #endif
>  
>  	/* IPI vectors for APIC spurious and error interrupts */


Best regards,
Yang