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path: root/arch/x86/kvm/page_track.c
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2016-11-04kvm/page_track: export symbols for external usageJike Song
Signed-off-by: Jike Song <jike.song@intel.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-04kvm/page_track: call notifiers with kvm_page_track_notifier_nodeJike Song
The user of page_track might needs extra information, so pass the kvm_page_track_notifier_node to callbacks. Signed-off-by: Jike Song <jike.song@intel.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-04KVM: x86: add track_flush_slot page track notifierXiaoguang Chen
When a memory slot is being moved or removed users of page track can be notified. So users can drop write-protection for the pages in that memory slot. This notifier type is needed by KVMGT to sync up its shadow page table when memory slot is being moved or removed. Register the notifier type track_flush_slot to receive memslot move and remove event. Reviewed-by: Xiao Guangrong <guangrong.xiao@intel.com> Signed-off-by: Chen Xiaoguang <xiaoguang.chen@intel.com> [Squashed commits to avoid bisection breakage and reworded the subject.] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-03-22KVM: page_track: fix access to NULL slotPaolo Bonzini
This happens when doing the reboot test from virt-tests: [ 131.833653] BUG: unable to handle kernel NULL pointer dereference at (null) [ 131.842461] IP: [<ffffffffa0950087>] kvm_page_track_is_active+0x17/0x60 [kvm] [ 131.850500] PGD 0 [ 131.852763] Oops: 0000 [#1] SMP [ 132.007188] task: ffff880075fbc500 ti: ffff880850a3c000 task.ti: ffff880850a3c000 [ 132.138891] Call Trace: [ 132.141639] [<ffffffffa092bd11>] page_fault_handle_page_track+0x31/0x40 [kvm] [ 132.149732] [<ffffffffa093380f>] paging64_page_fault+0xff/0x910 [kvm] [ 132.172159] [<ffffffffa092c734>] kvm_mmu_page_fault+0x64/0x110 [kvm] [ 132.179372] [<ffffffffa06743c2>] handle_exception+0x1b2/0x430 [kvm_intel] [ 132.187072] [<ffffffffa067a301>] vmx_handle_exit+0x1e1/0xc50 [kvm_intel] ... Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Fixes: 3d0c27ad6ee465f174b09ee99fcaf189c57d567a Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: page track: add notifier supportXiao Guangrong
Notifier list is introduced so that any node wants to receive the track event can register to the list Two APIs are introduced here: - kvm_page_track_register_notifier(): register the notifier to receive track event - kvm_page_track_unregister_notifier(): stop receiving track event by unregister the notifier The callback, node->track_write() is called when a write access on the write tracked page happens Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: let page fault handler be aware tracked pageXiao Guangrong
The page fault caused by write access on the write tracked page can not be fixed, it always need to be emulated. page_fault_handle_page_track() is the fast path we introduce here to skip holding mmu-lock and shadow page table walking However, if the page table is not present, it is worth making the page table entry present and readonly to make the read access happy mmu_need_write_protect() need to be cooked to avoid page becoming writable when making page table present or sync/prefetch shadow page table entries Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: page track: introduce kvm_slot_page_track_{add,remove}_pageXiao Guangrong
These two functions are the user APIs: - kvm_slot_page_track_add_page(): add the page to the tracking pool after that later specified access on that page will be tracked - kvm_slot_page_track_remove_page(): remove the page from the tracking pool, the specified access on the page is not tracked after the last user is gone Both of these are called under the protection both of mmu-lock and kvm->srcu or kvm->slots_lock Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: page track: add the framework of guest page trackingXiao Guangrong
The array, gfn_track[mode][gfn], is introduced in memory slot for every guest page, this is the tracking count for the gust page on different modes. If the page is tracked then the count is increased, the page is not tracked after the count reaches zero We use 'unsigned short' as the tracking count which should be enough as shadow page table only can use 2^14 (2^3 for level, 2^1 for cr4_pae, 2^2 for quadrant, 2^3 for access, 2^1 for nxe, 2^1 for cr0_wp, 2^1 for smep_andnot_wp, 2^1 for smap_andnot_wp, and 2^1 for smm) at most, there is enough room for other trackers Two callbacks, kvm_page_track_create_memslot() and kvm_page_track_free_memslot() are implemented in this patch, they are internally used to initialize and reclaim the memory of the array Currently, only write track mode is supported Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>