Commit Graph

10 Commits

Author SHA1 Message Date
Xiao Guangrong 32cad84f44 KVM: do not release the error page
After commit a2766325cf, the error page is replaced by the
error code, it need not be released anymore

[ The patch has been compiling tested for powerpc ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-06 16:04:58 +03:00
Xiao Guangrong 6cede2e679 KVM: introduce KVM_ERR_PTR_BAD_PAGE
It is used to eliminate the overload of function call and cleanup
the code

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-06 16:04:55 +03:00
Xiao Guangrong a2766325cf KVM: remove dummy pages
Currently, kvm allocates some pages and use them as error indicators,
it wastes memory and is not good for scalability

Base on Avi's suggestion, we use the error codes instead of these pages
to indicate the error conditions

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-07-26 11:55:34 +03:00
Xiao Guangrong 2b4b5af8f8 KVM: use kvm_release_page_clean to release the page
In kvm_async_pf_wakeup_all, it uses bad_page to generate broadcast wakeup,
and uses put_page to release bad_page, the work depends on the fact that
bad_page is the normal page. But we will use the error code instead of
bad_page, so use kvm_release_page_clean to release the page which will
release the error code properly

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-07-26 11:55:31 +03:00
Xiao Guangrong 64f638c7c4 KVM: fix the race while wakeup all pv guest
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 <xiaoguangrong@cn.fujitsu.com>
Acked-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:29:03 +02:00
Xiao Guangrong 15096ffcea KVM: handle more completed apfs if possible
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 <xiaoguangrong@cn.fujitsu.com>
Acked-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:29:01 +02:00
Gleb Natapov 7c90705bf2 KVM: Inject asynchronous page fault into a PV guest if page is swapped out.
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 <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:23:17 +02:00
Gleb Natapov 344d9588a9 KVM: Add PV MSR to enable asynchronous page faults delivery.
Guest enables async PF vcpu functionality using this MSR.

Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:23:12 +02:00
Gleb Natapov 56028d0861 KVM: Retry fault before vmentry
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 <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:23:06 +02:00
Gleb Natapov af585b921e KVM: Halt vcpu if page it tries to access is swapped out
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 <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:21:39 +02:00