Create access bitmap for SPP subpages, the bitmap can
be 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@xxxxxxxxxxxxxxx>
Signed-off-by: He Chen <he.chen@xxxxxxxxxxxxxxx>
Co-developed-by: Zhang Yi <yi.z.zhang@xxxxxxxxxxxxxxx>
Signed-off-by: Zhang Yi <yi.z.zhang@xxxxxxxxxxxxxxx>
Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 3 +
arch/x86/kvm/vmx/spp.c | 311 +++++++++++++++++++++++++++++++-
arch/x86/kvm/vmx/spp.h | 7 +
include/uapi/linux/kvm.h | 9 +
4 files changed, 325 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index eb18f4dd993d..cc38670a0c45 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -799,6 +799,7 @@ 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];
};
@@ -939,6 +940,8 @@ struct kvm_arch {
bool exception_payload_enabled;
struct kvm_pmu_event_filter *pmu_event_filter;
+ bool spp_active;
+
};
struct kvm_vm_stat {
diff --git a/arch/x86/kvm/vmx/spp.c b/arch/x86/kvm/vmx/spp.c
index 27fef18fcc4e..964d31fe9426 100644
--- a/arch/x86/kvm/vmx/spp.c
+++ b/arch/x86/kvm/vmx/spp.c
@@ -22,6 +22,15 @@ static int is_spp_shadow_present(u64 pte)
return pte & PT_PRESENT_MASK;
}
+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];
+}
+EXPORT_SYMBOL_GPL(gfn_to_subpage_wp_info);
+
static bool __rmap_open_subpage_bit(struct kvm *kvm,
struct kvm_rmap_head *rmap_head)
{
@@ -179,6 +188,24 @@ bool is_spp_spte(struct kvm_mmu_page *sp)
return sp->role.spp;
}
+/*
+ * all vcpus share the same SPPT, vcpu->arch.mmu->sppt_root points to same
+ * SPPT root page, so any vcpu will do.
+ */
+static struct kvm_vcpu *kvm_spp_get_vcpu(struct kvm *kvm)
+{
+ struct kvm_vcpu *vcpu = NULL;
+ int idx;
+
+ for (idx = 0; idx < atomic_read(&kvm->online_vcpus); idx++) {
+ vcpu = kvm_get_vcpu(kvm, idx);
+ if (vcpu)
+ break;
+ }
+
+ return vcpu;
+}
+
#define SPPT_ENTRY_PHA_MASK (0xFFFFFFFFFF << 12)
int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
@@ -198,11 +225,8 @@ int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
if (iter.level == PT_PAGE_TABLE_LEVEL) {
spp_spte = format_spp_spte(access_map);
old_spte = mmu_spte_get_lockless(iter.sptep);
- if (old_spte != spp_spte) {
+ if (old_spte != spp_spte)
spp_spte_set(iter.sptep, spp_spte);
- //kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
- kvm_flush_remote_tlbs(vcpu->kvm);
- }
ret = 0;
break;
}
@@ -226,11 +250,288 @@ int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
link_spp_shadow_page(vcpu, iter.sptep, sp);
}
}
-
+ kvm_flush_remote_tlbs(vcpu->kvm);
return ret;
}
EXPORT_SYMBOL_GPL(kvm_spp_setup_structure);
+int vmx_spp_flush_sppt(struct kvm *kvm, struct kvm_subpage *spp_info)
+{
+ struct kvm_shadow_walk_iterator iter;
+ struct kvm_vcpu *vcpu;
+ gfn_t gfn = spp_info->base_gfn;
+ int npages = spp_info->npages;
+ u64 spde;
+ int i;
+
+ vcpu = kvm_spp_get_vcpu(kvm);
+ /* direct_map spp start */
+ if (!VALID_PAGE(vcpu->arch.mmu->sppt_root))
+ return -EFAULT;
+
+ for (i = 0; i < npages; ++i) {
+ for_each_shadow_spp_entry(vcpu, (u64)gfn << PAGE_SHIFT, iter) {
+ if (!is_spp_shadow_present(*iter.sptep))
+ break;
+
+ if (iter.level == PT_DIRECTORY_LEVEL) {
+ spde = *iter.sptep;
+ spde &= ~PT_PRESENT_MASK;
+ spp_spte_set(iter.sptep, spde);
+ break;
+ }
+ }
+ gfn++;
+ }
+ kvm_flush_remote_tlbs(kvm);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vmx_spp_flush_sppt);
+
+static int kvm_spp_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;
+}
+
+int vmx_spp_init(struct kvm *kvm)
+{
+ int i, ret;
+ struct kvm_vcpu *vcpu;
+ int root_level;
+ struct kvm_mmu_page *ssp_sp;
+ bool first_root = true;
+
+ /* SPP feature is exclusive with nested VM.*/
+ if (kvm_x86_ops->get_nested_state)
+ return -EPERM;
+
+ if (kvm->arch.spp_active)
+ return 0;
+
+ ret = kvm_spp_create_bitmaps(kvm);
+
+ if (ret)
+ return ret;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (first_root) {
+ /* prepare caches for SPP setup.*/
+ mmu_topup_memory_caches(vcpu);
+ root_level = vcpu->arch.mmu->shadow_root_level;
+ ssp_sp = kvm_spp_get_page(vcpu, 0, root_level);
+ first_root = false;
+ }
+ ++ssp_sp->root_count;
+ vcpu->arch.mmu->sppt_root = __pa(ssp_sp->spt);
+ kvm_make_request(KVM_REQ_LOAD_CR3, vcpu);
+ }
+
+ kvm->arch.spp_active = true;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(vmx_spp_init);
+
+int kvm_spp_get_permission(struct kvm *kvm, struct kvm_subpage *spp_info)
+{
+ u32 *access = spp_info->access_map;
+ gfn_t gfn = spp_info->base_gfn;
+ int npages = spp_info->npages;
+ struct kvm_memory_slot *slot;
+ int i;
+
+ if (!kvm->arch.spp_active)
+ return -ENODEV;
+
+ for (i = 0; i < npages; i++, gfn++) {
+ slot = gfn_to_memslot(kvm, gfn);
+ if (!slot)
+ return -EFAULT;
+ access[i] = *gfn_to_subpage_wp_info(slot, gfn);
+ }
+
+ return i;
+}
+EXPORT_SYMBOL_GPL(kvm_spp_get_permission);
+
+static void kvm_spp_zap_pte(struct kvm *kvm, u64 *spte, int level)
+{
+ u64 pte;
+
+ pte = *spte;
+ if (is_shadow_present_pte(pte) && is_last_spte(pte, level)) {
+ drop_spte(kvm, spte);
+ if (is_large_pte(pte))
+ --kvm->stat.lpages;
+ }
+}
+
+int kvm_spp_zap_entry(struct kvm *kvm, gfn_t gfn_lower, gfn_t gfn_upper,
+ u64 *sptep, int level)
+{
+ int page_num = KVM_PAGES_PER_HPAGE(level);
+ gfn_t gfn_max = (gfn_lower & ~(page_num - 1)) + page_num - 1;
+ int ret;
+
+ if (gfn_upper <= gfn_max)
+ ret = gfn_upper - gfn_lower + 1;
+ else
+ ret = gfn_max - gfn_lower + 1;
+
+ kvm_spp_zap_pte(kvm, sptep, level);
+ kvm_flush_remote_tlbs(kvm);
+
+ return ret;
+}
+
+int kvm_spp_set_permission(struct kvm *kvm, struct kvm_subpage *spp_info)
+{
+ u32 *access = spp_info->access_map;
+ gfn_t gfn = spp_info->base_gfn;
+ int npages = spp_info->npages;
+ struct kvm_memory_slot *slot;
+ struct kvm_subpage sbp = {0};
+ struct kvm_shadow_walk_iterator iterator;
+ struct kvm_vcpu *vcpu;
+ gfn_t max_gfn;
+ gfn_t old_gfn = gfn;
+ u32 *wp_map;
+ int i, count;
+
+ if (!kvm->arch.spp_active)
+ return -ENODEV;
+
+ if (npages > SUBPAGE_MAX_BITMAP)
+ return -EFAULT;
+
+ for (i = 0; i < npages; i++, gfn++) {
+ slot = gfn_to_memslot(kvm, gfn);
+ if (!slot)
+ return -EFAULT;
+
+ wp_map = gfn_to_subpage_wp_info(slot, gfn);
+ *wp_map = access[i];
+ }
+
+ gfn = old_gfn;
+ max_gfn = gfn + npages - 1;
+ vcpu = kvm_spp_get_vcpu(kvm);
+
+ if (!vcpu || (vcpu && !VALID_PAGE(vcpu->arch.mmu->root_hpa)))
+ goto out;
+
+ for (i = 0; gfn <= max_gfn; i++, gfn++) {
+ for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
+ if (!is_shadow_present_pte(*iterator.sptep))
+ break;
+
+ if (iterator.level == PT_PAGE_TABLE_LEVEL) {
+ sbp.base_gfn = gfn;
+ sbp.access_map[0] = access[i];
+ sbp.npages = 1;
+ if (kvm_spp_mark_protection(kvm, &sbp) < 0)
+ return -EFAULT;
+ break;
+ } else if (is_large_pte(*iterator.sptep)) {
+ count = kvm_spp_zap_entry(kvm, gfn, max_gfn,
+ iterator.sptep,
+ iterator.level);
+ if (count >= npages)
+ goto out;
+ gfn += count - 1;
+ }
+ }
+ }
+out:
+ return npages;
+}
+
+int kvm_spp_mark_protection(struct kvm *kvm, struct kvm_subpage *spp_info)
+{
+ u32 *access = spp_info->access_map;
+ gfn_t gfn = spp_info->base_gfn;
+ struct kvm_memory_slot *slot;
+ struct kvm_rmap_head *rmap_head;
+ int ret;
+
+ if (!kvm->arch.spp_active)
+ return -ENODEV;
+
+ slot = gfn_to_memslot(kvm, gfn);
+ if (!slot)
+ return -EFAULT;
+
+ /*
+ * check whether the target 4KB page exists in EPT leaf
+ * entry.If it's there, just flag SPP bit of the entry,
+ * defer the setup to SPPT miss induced vm-exit handler.
+ */
+ rmap_head = __gfn_to_rmap(gfn, PT_PAGE_TABLE_LEVEL, slot);
+
+ if (rmap_head->val) {
+ /*
+ * if all subpages are not writable, open SPP bit in
+ * EPT leaf entry to enable SPP protection for
+ * corresponding page.
+ */
+ if (access[0] != FULL_SPP_ACCESS) {
+ ret = kvm_spp_open_write_protect(kvm, slot, gfn);
+ if (ret)
+ return ret;
+ } else {
+ ret = kvm_spp_clear_write_protect(kvm, slot, gfn);
+ if (ret)
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+void kvm_spp_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;
+ }
+}
+
inline u64 construct_spptp(unsigned long root_hpa)
{
return root_hpa & PAGE_MASK;
diff --git a/arch/x86/kvm/vmx/spp.h b/arch/x86/kvm/vmx/spp.h
index 25a23a4277eb..56b287ec15fd 100644
--- a/arch/x86/kvm/vmx/spp.h
+++ b/arch/x86/kvm/vmx/spp.h
@@ -2,9 +2,16 @@
#ifndef __KVM_X86_VMX_SPP_H
#define __KVM_X86_VMX_SPP_H
+#define FULL_SPP_ACCESS ((u32)((1ULL << 32) - 1))
+
bool is_spp_spte(struct kvm_mmu_page *sp);
inline u64 construct_spptp(unsigned long root_hpa);
int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
u32 access_map, gfn_t gfn);
+int vmx_spp_flush_sppt(struct kvm *kvm, struct kvm_subpage *spp_info);
+void kvm_spp_free_memslot(struct kvm_memory_slot *free,
+ struct kvm_memory_slot *dont);
+int vmx_spp_init(struct kvm *kvm);
+u32 *gfn_to_subpage_wp_info(struct kvm_memory_slot *slot, gfn_t gfn);
#endif /* __KVM_X86_VMX_SPP_H */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 5e3f12d5359e..9460830de536 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -102,6 +102,15 @@ struct kvm_userspace_memory_region {
__u64 userspace_addr; /* start of the userspace allocated memory */
};
+/* for KVM_SUBPAGES_GET_ACCESS and KVM_SUBPAGES_SET_ACCESS */
+#define SUBPAGE_MAX_BITMAP 64
+struct kvm_subpage {
+ __u64 base_gfn;
+ __u64 npages;
+ /* sub-page write-access bitmap array */
+ __u32 access_map[SUBPAGE_MAX_BITMAP];
+};
+
/*
* The bit 0 ~ bit 15 of kvm_memory_region::flags are visible for userspace,
* other bits are reserved for kvm internal use which are defined in
--
2.17.2
