[Xen-devel] Re: [PATCH][RFC] Support S3 for MSI interrupt in latest kernel dom0

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 17/12/2008 12:11, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:

> In latest kernel, the pci_save_state will not try to save msi/x_state anymore,
> instead, it will try to restore msi state when resume using kernel's msi data
> structure. This cause trouble for us, since thoese MSI data structure is
> meaningless in Xen environment.
> 
> Several option to resolve this issue:
> a) Change the latest kernel (as dom0) to still to save/restore the msi content
> b) Add a new hypercall, so when dom0 try to restore dom0, it will instruct Xen
> HV to restore the content based on Xen's MSI data structure

Could Xen remember the MSI state automatically, as it does for IO-APIC
presumably already? It knows what vectors are routed where at least, even if
dom0 has to reprogram the PCI device itself.

I'm not sure about option C. I didn't really understand the patch, but it
smelt like a hack.

 -- Keir




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