Re: [PATCH v1 07/11] KVM: s390: Move all code into kvm_arch_prepare_memory_region()

From: Christian Borntraeger

Date: Wed Aug 12 2026 - 04:44:41 EST


Am 11.08.26 um 17:56 schrieb Claudio Imbrenda:
Move all code from kvm_arch_commit_memory_region() into
kvm_arch_prepare_memory_region(). This allows the function to fail
gracefully if needed. The previous behaviour was to print a warning and
continue execution with page tables incosistent with the memslots.

The new kvm_s390_mmu_cache_extended_topup() function is used to
guarantee that the necessary DAT table updates can be performed
successfully.

Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")

Uhh, this feels pretty large for stable. sashiko founnd the KVM_BUG_ON return code
but this is hard tor review.


Another think.
kvm_s390_mmu_cache_extended_topup() asks for up to 32 order-2 allocations,
roughly 512 KiB. Even for a delete?