From 21ebbedaddf25a35a70fedc001ba7e5f5b9129bc Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Wed, 24 Feb 2016 17:51:09 +0800 Subject: [PATCH] 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/include/asm/kvm_host.h | 10 +++++++ arch/x86/include/asm/kvm_page_track.h | 13 +++++++++ arch/x86/kvm/Makefile | 3 +- arch/x86/kvm/page_track.c | 52 +++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 5 ++++ 5 files changed, 82 insertions(+), 1 deletion(-) create mode 100644 arch/x86/include/asm/kvm_page_track.h create mode 100644 arch/x86/kvm/page_track.c diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 1f7fed5..71e43fe 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -32,6 +32,7 @@ #include #include #include +#include #define KVM_MAX_VCPUS 255 #define KVM_SOFT_MAX_VCPUS 160 @@ -214,6 +215,14 @@ struct kvm_mmu_memory_cache { void *objects[KVM_NR_MEM_OBJS]; }; +/* + * the pages used as guest page table on soft mmu are tracked by + * kvm_memory_slot.arch.gfn_track which is 16 bits, so the role bits used + * by indirect shadow page can not be more than 15 bits. + * + * Currently, we used 14 bits that are @level, @cr4_pae, @quadrant, @access, + * @nxe, @cr0_wp, @smep_andnot_wp and @smap_andnot_wp. + */ union kvm_mmu_page_role { unsigned word; struct { @@ -650,6 +659,7 @@ struct kvm_lpage_info { struct kvm_arch_memory_slot { struct kvm_rmap_head *rmap[KVM_NR_PAGE_SIZES]; struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1]; + unsigned short *gfn_track[KVM_PAGE_TRACK_MAX]; }; /* diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h new file mode 100644 index 0000000..55200406 --- /dev/null +++ b/arch/x86/include/asm/kvm_page_track.h @@ -0,0 +1,13 @@ +#ifndef _ASM_X86_KVM_PAGE_TRACK_H +#define _ASM_X86_KVM_PAGE_TRACK_H + +enum kvm_page_track_mode { + KVM_PAGE_TRACK_WRITE, + KVM_PAGE_TRACK_MAX, +}; + +void kvm_page_track_free_memslot(struct kvm_memory_slot *free, + struct kvm_memory_slot *dont); +int kvm_page_track_create_memslot(struct kvm_memory_slot *slot, + unsigned long npages); +#endif diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile index a1ff508..464fa47 100644 --- a/arch/x86/kvm/Makefile +++ b/arch/x86/kvm/Makefile @@ -13,9 +13,10 @@ kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o kvm-y += x86.o mmu.o emulate.o i8259.o irq.o lapic.o \ i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \ - hyperv.o + hyperv.o page_track.o kvm-$(CONFIG_KVM_DEVICE_ASSIGNMENT) += assigned-dev.o iommu.o + kvm-intel-y += vmx.o pmu_intel.o kvm-amd-y += svm.o pmu_amd.o diff --git a/arch/x86/kvm/page_track.c b/arch/x86/kvm/page_track.c new file mode 100644 index 0000000..8c396d0 --- /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; +} diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 668625e..7b4cfea 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7871,6 +7871,8 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free, free->arch.lpage_info[i - 1] = NULL; } } + + kvm_page_track_free_memslot(free, dont); } int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, @@ -7919,6 +7921,9 @@ int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, } } + if (kvm_page_track_create_memslot(slot, npages)) + goto out_free; + return 0; out_free: -- 2.7.4