rt-thread vmm 排程問題

发布于 2014-12-23 12:01:42 浏览：3700 订阅该版

11 个回答

reliveinfire 2014-12-23

这家伙很懒，什么也没写！

由vector_irq 追起
一般處理interrupt 的流程,

後續,

```
    /* check whether we need to do IRQ routing
     * ensure the int is disabled. Or there will be an infinite loop. */
    ldr     r0, =rt_current_thread
    ldr     r0, [r0]
    ldr     r1, =vmm_thread
    cmp     r0, r1
    beq     switch_to_guest
```

不是很理解這邊的設計, 與vmm_thread的關聯性, 
找不到vmm_thread的 thread function 內容.

猜測, 是否 每次rtt thread 啟動, 會將自己複製到 vmm_thread的位置? 以做判斷目前被中斷的thread 為guest_os 或者 rtt thread?

```
switch_to_guest:
#ifdef RT_VMM_USING_DOMAIN
    @ We are going to execute rt-thread code but accessing the content of the
    @ guest. So switch to super domain.
    ldr     r1, =super_domain_val
    ldr     r0, [r1]
    mcr     p15, 0, r0, c3, c0
#endif
        /* check whether there is a pending interrupt for Guest OS */
        bl      vmm_virq_check

#ifdef RT_VMM_USING_DOMAIN
    @ All done, restore the guest domain.
    mcr     p15, 0, r5, c3, c0
#endif

cmp     r0, #0x0
        beq     route_irq_to_guest

ldmfd   sp!, {r0-r12,lr}
    subs    pc, lr, #4

route_irq_to_guest:
    ldmfd   sp!, {r0-r12,lr}
    b       orig_irq_isr
#endif /* RT_USING_VMM */
```

這段, route_irq_to_guest 的用意不太了解. 為何要在 switch_to_guest 的狀態下才將 pending virq 送至guest os?

還請了解這段設計的先進指教
感謝