Re: Getting Synchronous Exception while run avocado-vt tests

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

On Thu, 22 Aug 2019 at 10:40, Zhanghailiang
<zhang.zhanghailiang@huawei.com> wrote:
>
> Hi All,
>
>
>
> We caught an ‘Synchronous Exception’ error while booting VM with uefi firmware in the avocado-vt tests.
>
> The Edk2 version we used is edk2-stable201905. The qemu version is qemu-4.0.0 and kernel version is 4.19.0.
>
> Parts of the log we got from serial is bellow, you can get the full log from attachment.
>
> We can easily reproduce this issue with running avocado-vt tests. Actually, we tried the new edk2 from upstream,
>
> It is still can be reproduced.
>
>
>
> Reproduce command:
>
> # avocado run type_specific.io-github-autotest-qemu.qmp_event_notification --vt-type qemu --vt-guest-os Guest.Linux.Fedora.29
>
>
>
> Qemu command is :
>
..
>
> It reports that this is a alignment fault from log, We analyzed the callstack from log:
>
> VirtioScsiPassThru-> VirtioFlush->virtio10SetQueueNotify->Virtio10Transfer->PciIoMemWrite-> CpuMemoryServiceWrite-> MmioWrite32 <- here, the address is not align.
>

The faulting address ends in 0x16, so the access is to the QueueSelect
field in VIRTIO_PCI_COMMON_CFG. This is a UINT16 field, so the access
should be 16-bit not 32-bits wide.

Could you dump the instructions leading up to the first
Virtio10Transfer() call in Virtio10SetQueueNotify()? (from
Build/ArmVirtQemu-AARCH64/DEBUG_GCC49/AARCH64/OvmfPkg/Virtio10Dxe/Virtio10/DEBUG/Virtio10.dll)

    2280:       aa0103e5        mov     x5, x1
    2284:       d2800044        mov     x4, #0x2                        // #2
    2288:       d28002c3        mov     x3, #0x16                       // #22
    228c:       52800002        mov     w2, #0x0                        // #0
    2290:       aa0003e1        mov     x1, x0
    2294:       aa0603e0        mov     x0, x6
    2298:       97fffcf3        bl      1664 <Virtio10Transfer>

If the size is passed correctly here, we'll have to track down how the
call gets routed to Mmio32Write instead of Mmio16Write(). Do you have
any patches on top of edk2-stable-201905 ?