[PATCH 5.15.y 0/2] fix softlockups in stage2_apply_range()

Hi Stable Team, In 5.15, unmapping large kvm vms on arm64 can generate softlockups. My team has been hitting this when tearing down VMs > 100Gb in size.

Oliver fixed this with the attached patches. They've been in mainline since 6.1.

I tested on 5.15.150 with these patches applied. When they're present, both the dirty_log_perf_test detailed in the second patch, and kvm_page_table_test no longer generate softlockups when unmapping VMs with large memory configurations.

Would you please consider these patches for inclusion in an upcoming 5.15 release?

Thanks,

-K

Oliver Upton (2): KVM: arm64: Work out supported block level at compile time KVM: arm64: Limit stage2_apply_range() batch size to largest block

arch/arm64/include/asm/kvm_pgtable.h | 18 +++++++++++++----- arch/arm64/include/asm/stage2_pgtable.h | 20 -------------------- arch/arm64/kvm/mmu.c | 9 ++++++++- 3 files changed, 21 insertions(+), 26 deletions(-)