From 21ebbedaddf25a35a70fedc001ba7e5f5b9129bc Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 24 Feb 2016 17:51:09 +0800 Subject: KVM: page track: add the framework of guest page tracking 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 Signed-off-by: Paolo Bonzini --- arch/x86/kvm/page_track.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 arch/x86/kvm/page_track.c (limited to 'arch/x86/kvm/page_track.c') diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c new file mode 100644 index 000000000000..8c396d08c0a4 --- /dev/null +++ b/arch/x86/kvm/page_track.c @@ -0,0 +1,52 @@ +/* + * Support KVM gust page tracking + * + * This feature allows us to track page access in guest. Currently, only + * write access is tracked. + * + * Copyright(C) 2015 Intel Corporation. + * + * Author: + * Xiao Guangrong + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + */ + +#include +#include +#include + +#include "mmu.h" + +void kvm_page_track_free_memslot(struct kvm_memory_slot *free, + struct kvm_memory_slot *dont) +{ + int i; + + for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) + if (!dont || free->arch.gfn_track[i] != + dont->arch.gfn_track[i]) { + kvfree(free->arch.gfn_track[i]); + free->arch.gfn_track[i] = NULL; + } +} + +int kvm_page_track_create_memslot(struct kvm_memory_slot *slot, + unsigned long npages) +{ + int i; + + for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) { + slot->arch.gfn_track[i] = kvm_kvzalloc(npages * + sizeof(*slot->arch.gfn_track[i])); + if (!slot->arch.gfn_track[i]) + goto track_free; + } + + return 0; + +track_free: + kvm_page_track_free_memslot(slot, NULL); + return -ENOMEM; +} -- cgit v1.2.3