linux-toradex.git/virt/kvm/async_pf.c, branch v3.0.95

KVM: fix the race while wakeup all pv guest

2011-01-12T09:29:03+00:00

In kvm_async_pf_wakeup_all(), we add a dummy apf to vcpu->async_pf.done
without holding vcpu->async_pf.lock, it will break if we are handling apfs
at this time.

Also use 'list_empty_careful()' instead of 'list_empty()'

Signed-off-by: Xiao Guangrong 
Acked-by: Gleb Natapov 
Signed-off-by: Marcelo Tosatti

KVM: handle more completed apfs if possible

2011-01-12T09:29:01+00:00

If it's no need to inject async #PF to PV guest we can handle
more completed apfs at one time, so we can retry guest #PF
as early as possible

Signed-off-by: Xiao Guangrong 
Acked-by: Gleb Natapov 
Signed-off-by: Marcelo Tosatti

KVM: Inject asynchronous page fault into a PV guest if page is swapped out.

2011-01-12T09:23:17+00:00

Send async page fault to a PV guest if it accesses swapped out memory.
Guest will choose another task to run upon receiving the fault.

Allow async page fault injection only when guest is in user mode since
otherwise guest may be in non-sleepable context and will not be able
to reschedule.

Vcpu will be halted if guest will fault on the same page again or if
vcpu executes kernel code.

Acked-by: Rik van Riel 
Signed-off-by: Gleb Natapov 
Signed-off-by: Marcelo Tosatti

KVM: Add PV MSR to enable asynchronous page faults delivery.

2011-01-12T09:23:12+00:00

Guest enables async PF vcpu functionality using this MSR.

Reviewed-by: Rik van Riel 
Signed-off-by: Gleb Natapov 
Signed-off-by: Marcelo Tosatti

KVM: Retry fault before vmentry

2011-01-12T09:23:06+00:00

When page is swapped in it is mapped into guest memory only after guest
tries to access it again and generate another fault. To save this fault
we can map it immediately since we know that guest is going to access
the page. Do it only when tdp is enabled for now. Shadow paging case is
more complicated. CR[034] and EFER registers should be switched before
doing mapping and then switched back.

Acked-by: Rik van Riel 
Signed-off-by: Gleb Natapov 
Signed-off-by: Marcelo Tosatti

KVM: Halt vcpu if page it tries to access is swapped out

2011-01-12T09:21:39+00:00

If a guest accesses swapped out memory do not swap it in from vcpu thread
context. Schedule work to do swapping and put vcpu into halted state
instead.

Interrupts will still be delivered to the guest and if interrupt will
cause reschedule guest will continue to run another task.

[avi: remove call to get_user_pages_noio(), nacked by Linus; this
      makes everything synchrnous again]

Acked-by: Rik van Riel 
Signed-off-by: Gleb Natapov 
Signed-off-by: Marcelo Tosatti