Re: [PATCH v3 3/5] KVM: s390: vsie: Fix unshadowing logic

[Christian Borntraeger]

Am 19.05.26 um 17:01 schrieb Claudio Imbrenda:
> In some cases (i.e. under extreme memory pressure on the host),
> attempting to shadow memory will result in the same memory being
> unshadowed, causing a loop.
>
> Add a PGSTE bit to distinguish between shadowed memory and shadowed DAT
> tables, fix the unshadowing logic in _gmap_ptep_xchg() to prevent
> unnecessary unshadowing and perform better checks.
>
> Also fix the unshadowing logic in _gmap_crstep_xchg_atomic() which did
> not unshadow properly when the large page would become unprotected.
>
> Opportunistically add a check in gmap_protect_rmap() to make sure it
> won't be called with level == TABLE_TYPE_PAGE_TABLE.
>
> Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> Fixes: a2c17f9270cc ("KVM: s390: New gmap code")

Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>