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| author | Peter Xu <peterx@redhat.com> | 2020-09-30 21:22:24 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-11-15 09:49:16 -0500 |
| commit | b2cc64c4f3829c25b618f23f472a493668d9cb80 (patch) | |
| tree | e7b47dbca1724c1598809f02a94a8cfb8f37502f /virt | |
| parent | fb04a1eddb1a65b6588a021bdc132270d5ae48bb (diff) | |
| download | lwn-b2cc64c4f3829c25b618f23f472a493668d9cb80.tar.gz lwn-b2cc64c4f3829c25b618f23f472a493668d9cb80.zip | |
KVM: Make dirty ring exclusive to dirty bitmap log
There's no good reason to use both the dirty bitmap logging and the
new dirty ring buffer to track dirty bits. We should be able to even
support both of them at the same time, but it could complicate things
which could actually help little. Let's simply make it the rule
before we enable dirty ring on any arch, that we don't allow these two
interfaces to be used together.
The big world switch would be KVM_CAP_DIRTY_LOG_RING capability
enablement. That's where we'll switch from the default dirty logging
way to the dirty ring way. As long as kvm->dirty_ring_size is setup
correctly, we'll once and for all switch to the dirty ring buffer mode
for the current virtual machine.
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201001012224.5818-1-peterx@redhat.com>
[Change errno from EINVAL to ENXIO. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 78ef414512bf..110aa5cc0c93 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1426,6 +1426,10 @@ int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, unsigned long n; unsigned long any = 0; + /* Dirty ring tracking is exclusive to dirty log tracking */ + if (kvm->dirty_ring_size) + return -ENXIO; + *memslot = NULL; *is_dirty = 0; @@ -1487,6 +1491,10 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log) unsigned long *dirty_bitmap_buffer; bool flush; + /* Dirty ring tracking is exclusive to dirty log tracking */ + if (kvm->dirty_ring_size) + return -ENXIO; + as_id = log->slot >> 16; id = (u16)log->slot; if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) @@ -1595,6 +1603,10 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm, unsigned long *dirty_bitmap_buffer; bool flush; + /* Dirty ring tracking is exclusive to dirty log tracking */ + if (kvm->dirty_ring_size) + return -ENXIO; + as_id = log->slot >> 16; id = (u16)log->slot; if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) |