linux-kernel - [PATCH v2 0/5] KVM: s390: vsie: fixes and cleanups

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Date:   Fri,  3 Apr 2020 17:30:45 +0200
From:   David Hildenbrand <david@...hat.com>
To:     kvm@...r.kernel.org
Cc:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        David Hildenbrand <david@...hat.com>
Subject: [PATCH v2 0/5] KVM: s390: vsie: fixes and cleanups

Some vsie/gmap fixes and two cleanups/improvements.

Patch #1 fixes an issue reported by Janosch. It was never observed so far,
because KVM usually doesn't use a region 1 table for it's guest (unless
memory would be exceeding something like 16 EB, which isn't even supported
by the HW). Older QEMU+KVM or other hypervisors can trigger this.

Patch #2 fixes a code path that probably was never taken and will most
probably not be taken very often in the future - unless somebody really
messes up the page tables for a guest (or writes a test for it). At some
point, a test case for this would be nice.

Patch #3 fixes a rare possible race. Don't think this is stable material.

Gave it some testing with my limited access to somewhat-fast s390x
machines. Booted a Linux kernel, supplying all possible number of
page table hiearchies.

v1 -> v2:
- "KVM: s390: vsie: Fix region 1 ASCE sanity shadow address checks"
-- Fix WARN_ON_ONCE
- "gmap_table_walk() simplifications"
-- Also init "table" directly

David Hildenbrand (5):
  KVM: s390: vsie: Fix region 1 ASCE sanity shadow address checks
  KVM: s390: vsie: Fix delivery of addressing exceptions
  KVM: s390: vsie: Fix possible race when shadowing region 3 tables
  KVM: s390: vsie: Move conditional reschedule
  KVM: s390: vsie: gmap_table_walk() simplifications

 arch/s390/kvm/vsie.c |  4 ++--
 arch/s390/mm/gmap.c  | 17 +++++++++++------
 2 files changed, 13 insertions(+), 8 deletions(-)

-- 
2.25.1