On Fri, May 17, 2013 at 02:41:30PM +0200, Christian Borntraeger wrote:
> Gleb, Paolo, Marcelo,
>
Applied, thanks.
> here are some low level changes to kvm on s390 that we have been
> cooking for a while now.
>
> Patch "s390/pgtable: fix ipte notify bit" will go via Martins
> tree into 3.10, but is included to reduce the amount of merge
> conflicts.
>
> Patch "s390: fix gmap_ipte_notifier vs. software dirty pages"
> will also go via Martins tree into 3.10 and it fixes a hang with
> heavy host paging and KVM. This is optional for merging, but
> makes testing on kvm/next easier.
>
> This series addresses 2 problems:
> - paging of guest prefix page
> - RCU timeouts
>
> The first problem is basically that we must not have the host pte
> invalid or r/o for the guest prefix pages. (everything else has fully
> nested paging but the prefix page must not cause host faults).
> It is not enough to pin the page, also the pte has to be r/w all the
> time. Mlocking is not enough due to memory compaction, malicious
> unmapping etc.
> We use the existing callback mechanism of the s390 page table functions
> to kick guests out of SIE and hold them until this is done. We cant
> use the existing kick functions since we must hold a pgste lock while
> we wait for SIE to exit and IPIs might dead lock.
>
> The second problem is that with KVM on s390 we have seen very long
> RCU stalls due to SIE not exiting on interrupts. Instead of returning
> to SIE, we now force an exit into the kvm module, which then does the
> guest exit/enter magic, fixing rcu.
>
> The whole bunch is probably too complex for 3.10, so please queue for
> 3.11
>
> Christian Borntraeger (5):
> s390/pgtable: fix ipte notify bit
> s390/kvm: Mark if a cpu is in SIE
> s390/kvm: Provide a way to prevent reentering SIE
> s390/kvm: Kick guests out of sie if prefix page host pte is touched
> s390: fix gmap_ipte_notifier vs. software dirty pages
>
> Martin Schwidefsky (3):
> s390/kvm: fix psw rewinding in handle_skey
> s390/kvm: rename RCP_xxx defines to PGSTE_xxx
> s390/kvm: avoid automatic sie reentry
>
> arch/s390/include/asm/kvm_host.h | 8 +++-
> arch/s390/include/asm/pgtable.h | 83
> +++++++++++++++++++---------------------
> arch/s390/kernel/asm-offsets.c | 3 ++
> arch/s390/kernel/entry64.S | 80 ++++++++++++++++++--------------------
> arch/s390/kvm/intercept.c | 39 +------------------
> arch/s390/kvm/kvm-s390.c | 81 ++++++++++++++++++++++++++++++++++++++-
> arch/s390/kvm/kvm-s390.h | 5 +++
> arch/s390/kvm/priv.c | 3 +-
> arch/s390/mm/pgtable.c | 5 +--
> 9 files changed, 179 insertions(+), 128 deletions(-)
>
> --
> 1.8.1.4
--
Gleb.
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