Re: [RFC PATCH v2 0/4] Add KVM API for confidential guest live migration

[Tony Lindgren <tony.lindgren@linux.intel.com>]

On Thu, Oct 15, 2026 at 08:56:41PM -0700, Kishen Maloor wrote:
> On 10/8/26 11:11 PM, Tony Lindgren wrote:
> > On Fri, Sep 18, 2026 at 03:46:32PM +0300, Artem Bityutskiy wrote:
> >> In general, I feel like if buffer size is not enough, the uAPI could fill it
> >> with as much data as fits, and communicate back about what GPAs were
> >> exported. The caller could export the rest separately.
> > 
> > For the "communicate back about what GPAs were exported" part, how about
> > we add a u8 status array for the GPAs with the following generic values:
> > 
> > PENDING 0
> > DONE    1
> > RETRY   2
> > SKIPPED 3
> > FAILED  4
> > 
> > Memory transfer functions can report how many GPAs got transferred
> > (DONE and SKIPPED). A failed transfer can return an error and could
> > also set the FAILED state for the GPA entry where it makes sense.
> > 
> > The status could be also stuffed into the unused bits of the address
> > if that's preferred.
> 
> How might this information be used by userspace? Thus far, we haven't
> had a need for it AFAIU. From the userspace vantage point, the call
> either succeeds or fails.

Yup good point we have not needed this so far.