RE: [Xen-ia64-devel] [Patch] Speculative Load/Store to IO memory

[Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>]

Hi, Anthony

Thank you for yor comments.

>From the patch, guest executes ld.s on physical mode.
>Is this a cacheable address(region 0) or un-cacheable address(region 4)?
No, this guest work on virtual mode. My patch is for virtual mode.
This address is 0xa0000000fee00018.
When we found the isssue, arguments of mmio_access() are
 (f000000007980000, fee00018, f000000007987d80, 4, 4, 1), 
so I think it is un-cachable.

>
>If it is a un-cacheable address, 
>According to spec, the behavior of ld.s on un-cacheable page is undefined.
>We can set psr.ed directly.
>
Is cheking ma=4 better?

>If it is a cacheable address and it is IO address.
>I don't know the real behavior on native machine.
>So we need to get the real behavior first, then decide how to emulate it.
>I'm asking some exports, hope I can get the answer.
>
Thanks.
This issue is difficult to reproduce,
because we don't know step to reproduce.

Best Regards,

Akio Takebe


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