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  1. 05 6月, 2012 2 次提交
  3. 01 5月, 2012 1 次提交
  5. 24 4月, 2012 1 次提交
  7. 12 4月, 2012 1 次提交
    • A
      KVM: unmap pages from the iommu when slots are removed · 32f6daad
      由 Alex Williamson 提交于 
      We've been adding new mappings, but not destroying old mappings.
This can lead to a page leak as pages are pinned using
get_user_pages, but only unpinned with put_page if they still
exist in the memslots list on vm shutdown.  A memslot that is
destroyed while an iommu domain is enabled for the guest will
therefore result in an elevated page reference count that is
never cleared.

Additionally, without this fix, the iommu is only programmed
with the first translation for a gpa.  This can result in
peer-to-peer errors if a mapping is destroyed and replaced by a
new mapping at the same gpa as the iommu will still be pointing
to the original, pinned memory address.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
      32f6daad
  9. 08 4月, 2012 4 次提交
  11. 08 3月, 2012 7 次提交
  13. 05 3月, 2012 4 次提交
  15. 01 2月, 2012 1 次提交
    • T
      KVM: Fix __set_bit() race in mark_page_dirty() during dirty logging · 50e92b3c
      由 Takuya Yoshikawa 提交于 
      It is possible that the __set_bit() in mark_page_dirty() is called
simultaneously on the same region of memory, which may result in only
one bit being set, because some callers do not take mmu_lock before
mark_page_dirty().

This problem is hard to produce because when we reach mark_page_dirty()
beginning from, e.g., tdp_page_fault(), mmu_lock is being held during
__direct_map():  making kvm-unit-tests' dirty log api test write to two
pages concurrently was not useful for this reason.

So we have confirmed that there can actually be race condition by
checking if some callers really reach there without holding mmu_lock
using spin_is_locked():  probably they were from kvm_write_guest_page().

To fix this race, this patch changes the bit operation to the atomic
version:  note that nr_dirty_pages also suffers from the race but we do
not need exactly correct numbers for now.
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
      50e92b3c
  17. 27 12月, 2011 12 次提交
  19. 26 9月, 2011 1 次提交
    • S
      KVM: Intelligent device lookup on I/O bus · 743eeb0b
      由 Sasha Levin 提交于 
      Currently the method of dealing with an IO operation on a bus (PIO/MMIO)
is to call the read or write callback for each device registered
on the bus until we find a device which handles it.

Since the number of devices on a bus can be significant due to ioeventfds
and coalesced MMIO zones, this leads to a lot of overhead on each IO
operation.

Instead of registering devices, we now register ranges which points to
a device. Lookup is done using an efficient bsearch instead of a linear
search.

Performance test was conducted by comparing exit count per second with
200 ioeventfds created on one byte and the guest is trying to access a
different byte continuously (triggering usermode exits).
Before the patch the guest has achieved 259k exits per second, after the
patch the guest does 274k exits per second.

Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NSasha Levin <levinsasha928@gmail.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>
      743eeb0b
  21. 24 7月, 2011 2 次提交
  23. 12 7月, 2011 4 次提交