[PATCH RESEND v4 4/9] KVM: VMX: Introduce SPP access bitmap and operation functions

Yang Weijiang
2019-08-14T07:03:10Z

Create access bitmap for SPP subpages, 4KB/128B = 32bits,
for each 4KB physical page, 32bits are required. The bitmap can
be easily accessed with a gfn. The initial access bitmap for each
physical page is 0xFFFFFFFF, meaning SPP is not enabled for the
subpages.

Co-developed-by: He Chen <he.chen@linux.intel.com>
Signed-off-by: He Chen <he.chen@linux.intel.com>
Co-developed-by: Zhang Yi <yi.z.zhang@linux.intel.com>
Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/mmu.c | 50 +++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 11 ++++++++
3 files changed, 62 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 98e5158287d5..44f6e1757861 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -790,6 +790,7 @@ struct kvm_lpage_info {

struct kvm_arch_memory_slot {
struct kvm_rmap_head *rmap[KVM_NR_PAGE_SIZES];
+ u32 *subpage_wp_info;
struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1];
unsigned short *gfn_track[KVM_PAGE_TRACK_MAX];
};
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 494ad2038f36..16e390fd6e58 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1485,6 +1485,56 @@ static u64 *rmap_get_next(struct rmap_iterator *iter)
return sptep;
}

+#define FULL_SPP_ACCESS ((u32)((1ULL << 32) - 1))
+
+static int kvm_subpage_create_bitmaps(struct kvm *kvm)
+{
+ struct kvm_memslots *slots;
+ struct kvm_memory_slot *memslot;
+ int i, j, ret;
+ u32 *buff;
+
+ for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ slots = __kvm_memslots(kvm, i);
+ kvm_for_each_memslot(memslot, slots) {
+ buff = kvzalloc(memslot->npages*
+ sizeof(*memslot->arch.subpage_wp_info),
+ GFP_KERNEL);
+
+ if (!buff) {
+ ret = -ENOMEM;
+ goto out_free;
+ }
+ memslot->arch.subpage_wp_info = buff;
+
+ for(j = 0; j< memslot->npages; j++)
+ buff[j] = FULL_SPP_ACCESS;
+ }
+ }
+
+ return 0;
+out_free:
+ for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ slots = __kvm_memslots(kvm, i);
+ kvm_for_each_memslot(memslot, slots) {
+ if (memslot->arch.subpage_wp_info) {
+ kvfree(memslot->arch.subpage_wp_info);
+ memslot->arch.subpage_wp_info = NULL;
+ }
+ }
+ }
+
+ return ret;
+}
+
+static u32 *gfn_to_subpage_wp_info(struct kvm_memory_slot *slot, gfn_t gfn)
+{
+ unsigned long idx;
+
+ idx = gfn_to_index(gfn, slot->base_gfn, PT_PAGE_TABLE_LEVEL);
+ return &slot->arch.subpage_wp_info[idx];
+}
+
#define for_each_rmap_spte(_rmap_head_, _iter_, _spte_) \
for (_spte_ = rmap_get_first(_rmap_head_, _iter_); \
_spte_; _spte_ = rmap_get_next(_iter_))
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b5edc8e3ce1d..26e4c574731c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9317,6 +9317,17 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
kvm_hv_destroy_vm(kvm);
}

+void kvm_subpage_free_memslot(struct kvm_memory_slot *free,
+ struct kvm_memory_slot *dont)
+{
+
+ if (!dont || free->arch.subpage_wp_info !=
+ dont->arch.subpage_wp_info) {
+ kvfree(free->arch.subpage_wp_info);
+ free->arch.subpage_wp_info = NULL;
+ }
+}
+
void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
--
2.17.2