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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2013-03-25 17:22:48 +0100 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-04-02 16:14:07 +0300 |
| commit | 2cef4deb4018c02fb3cd08f76c8a988f7ddee480 (patch) | |
| tree | 8a97a4fa75b0b1c03afdb55b213e72b402e90673 /arch/s390/kvm/kvm-s390.c | |
| parent | 9a6d77d553856f461cdb5b6969b48da3a2b1f8e9 (diff) | |
| download | linux-2cef4deb4018c02fb3cd08f76c8a988f7ddee480.tar.bz2 | |
KVM: s390: Dont do a gmap update on minor memslot changes
Some memslot updates dont affect the gmap implementation,
e.g. setting/unsetting dirty tracking. Since a gmap update
will cause tlb flushes and segment table invalidations we
want to avoid that.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 33161b4a8280..f241e3315ebb 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1007,6 +1007,16 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, { int rc; + /* If the basics of the memslot do not change, we do not want + * to update the gmap. Every update causes several unnecessary + * segment translation exceptions. This is usually handled just + * fine by the normal fault handler + gmap, but it will also + * cause faults on the prefix page of running guest CPUs. + */ + if (old->userspace_addr == mem->userspace_addr && + old->base_gfn * PAGE_SIZE == mem->guest_phys_addr && + old->npages * PAGE_SIZE == mem->memory_size) + return; rc = gmap_map_segment(kvm->arch.gmap, mem->userspace_addr, mem->guest_phys_addr, mem->memory_size); |