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

["Xu, Anthony" <anthony.xu@xxxxxxxxx>]

Good finding!

One question
>From the patch, guest executes ld.s on physical mode.
Is this a cacheable address(region 0) or un-cacheable address(region 4)?

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.

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,
Anthony


>-----Original Message-----
>From: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
>[mailto:xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Akio Takebe
>Sent: 2007年5月17日 20:49
>To: xen-ia64-devel
>Subject: [Xen-ia64-devel] [Patch] Speculative Load/Store to IO memory
>
>Hi,
>
>We met a panic_domain(NULL, "Undefined IPI-LHF read!\n"),
>when we run test on Windows guest.
>When the issue was occurred, the guest did "ld4.s r49=[r27]".
>Reading IO memory by using "lds" is wrong.
>But if the instruction is speculative,
>Xen should set psr.ed then return to guest.
>
>Signed-off-by: Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>
>Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
>
>Best Regards,
>
>Akio Takebe

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