KVM: Remove memory alias support
As advertised in feature-removal-schedule.txt. Equivalent support is provided
by overlapping memory regions.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2ec2e27..a57cdea 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -69,8 +69,6 @@
#define IOPL_SHIFT 12
-#define KVM_ALIAS_SLOTS 4
-
#define KVM_PERMILLE_MMU_PAGES 20
#define KVM_MIN_ALLOC_MMU_PAGES 64
#define KVM_MMU_HASH_SHIFT 10
@@ -362,24 +360,7 @@
u64 hv_vapic;
};
-struct kvm_mem_alias {
- gfn_t base_gfn;
- unsigned long npages;
- gfn_t target_gfn;
-#define KVM_ALIAS_INVALID 1UL
- unsigned long flags;
-};
-
-#define KVM_ARCH_HAS_UNALIAS_INSTANTIATION
-
-struct kvm_mem_aliases {
- struct kvm_mem_alias aliases[KVM_ALIAS_SLOTS];
- int naliases;
-};
-
struct kvm_arch {
- struct kvm_mem_aliases *aliases;
-
unsigned int n_free_mmu_pages;
unsigned int n_requested_mmu_pages;
unsigned int n_alloc_mmu_pages;
@@ -655,8 +636,6 @@
int complete_pio(struct kvm_vcpu *vcpu);
bool kvm_check_iopl(struct kvm_vcpu *vcpu);
-struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn);
-
static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
{
struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8c2f580..c5501bc 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -434,9 +434,7 @@
int *write_count;
int i;
- gfn = unalias_gfn(kvm, gfn);
-
- slot = gfn_to_memslot_unaliased(kvm, gfn);
+ slot = gfn_to_memslot(kvm, gfn);
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
write_count = slot_largepage_idx(gfn, slot, i);
@@ -450,8 +448,7 @@
int *write_count;
int i;
- gfn = unalias_gfn(kvm, gfn);
- slot = gfn_to_memslot_unaliased(kvm, gfn);
+ slot = gfn_to_memslot(kvm, gfn);
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
write_count = slot_largepage_idx(gfn, slot, i);
@@ -467,8 +464,7 @@
struct kvm_memory_slot *slot;
int *largepage_idx;
- gfn = unalias_gfn(kvm, gfn);
- slot = gfn_to_memslot_unaliased(kvm, gfn);
+ slot = gfn_to_memslot(kvm, gfn);
if (slot) {
largepage_idx = slot_largepage_idx(gfn, slot, level);
return *largepage_idx;
@@ -521,7 +517,6 @@
/*
* Take gfn and return the reverse mapping to it.
- * Note: gfn must be unaliased before this function get called
*/
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int level)
@@ -561,7 +556,6 @@
if (!is_rmap_spte(*spte))
return count;
- gfn = unalias_gfn(vcpu->kvm, gfn);
sp = page_header(__pa(spte));
kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn);
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
@@ -698,7 +692,6 @@
u64 *spte;
int i, write_protected = 0;
- gfn = unalias_gfn(kvm, gfn);
rmapp = gfn_to_rmap(kvm, gfn, PT_PAGE_TABLE_LEVEL);
spte = rmap_next(kvm, rmapp, NULL);
@@ -885,7 +878,6 @@
sp = page_header(__pa(spte));
- gfn = unalias_gfn(vcpu->kvm, gfn);
rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
kvm_unmap_rmapp(vcpu->kvm, rmapp, 0);
@@ -3510,8 +3502,7 @@
if (sp->unsync)
continue;
- gfn = unalias_gfn(vcpu->kvm, sp->gfn);
- slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
+ slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
rmapp = &slot->rmap[gfn - slot->base_gfn];
spte = rmap_next(vcpu->kvm, rmapp, NULL);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 863920f..a21a86e 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -576,7 +576,6 @@
* Using the cached information from sp->gfns is safe because:
* - The spte has a reference to the struct page, so the pfn for a given gfn
* can't change unless all sptes pointing to it are nuked first.
- * - Alias changes zap the entire shadow cache.
*/
static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
bool clear_unsync)
@@ -611,7 +610,7 @@
return -EINVAL;
gfn = gpte_to_gfn(gpte);
- if (unalias_gfn(vcpu->kvm, gfn) != sp->gfns[i] ||
+ if (gfn != sp->gfns[i] ||
!is_present_gpte(gpte) || !(gpte & PT_ACCESSED_MASK)) {
u64 nonpresent;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8e60b6c..62596d3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2740,115 +2740,6 @@
return kvm->arch.n_alloc_mmu_pages;
}
-gfn_t unalias_gfn_instantiation(struct kvm *kvm, gfn_t gfn)
-{
- int i;
- struct kvm_mem_alias *alias;
- struct kvm_mem_aliases *aliases;
-
- aliases = kvm_aliases(kvm);
-
- for (i = 0; i < aliases->naliases; ++i) {
- alias = &aliases->aliases[i];
- if (alias->flags & KVM_ALIAS_INVALID)
- continue;
- if (gfn >= alias->base_gfn
- && gfn < alias->base_gfn + alias->npages)
- return alias->target_gfn + gfn - alias->base_gfn;
- }
- return gfn;
-}
-
-gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
-{
- int i;
- struct kvm_mem_alias *alias;
- struct kvm_mem_aliases *aliases;
-
- aliases = kvm_aliases(kvm);
-
- for (i = 0; i < aliases->naliases; ++i) {
- alias = &aliases->aliases[i];
- if (gfn >= alias->base_gfn
- && gfn < alias->base_gfn + alias->npages)
- return alias->target_gfn + gfn - alias->base_gfn;
- }
- return gfn;
-}
-
-/*
- * Set a new alias region. Aliases map a portion of physical memory into
- * another portion. This is useful for memory windows, for example the PC
- * VGA region.
- */
-static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
- struct kvm_memory_alias *alias)
-{
- int r, n;
- struct kvm_mem_alias *p;
- struct kvm_mem_aliases *aliases, *old_aliases;
-
- r = -EINVAL;
- /* General sanity checks */
- if (alias->memory_size & (PAGE_SIZE - 1))
- goto out;
- if (alias->guest_phys_addr & (PAGE_SIZE - 1))
- goto out;
- if (alias->slot >= KVM_ALIAS_SLOTS)
- goto out;
- if (alias->guest_phys_addr + alias->memory_size
- < alias->guest_phys_addr)
- goto out;
- if (alias->target_phys_addr + alias->memory_size
- < alias->target_phys_addr)
- goto out;
-
- r = -ENOMEM;
- aliases = kzalloc(sizeof(struct kvm_mem_aliases), GFP_KERNEL);
- if (!aliases)
- goto out;
-
- mutex_lock(&kvm->slots_lock);
-
- /* invalidate any gfn reference in case of deletion/shrinking */
- memcpy(aliases, kvm->arch.aliases, sizeof(struct kvm_mem_aliases));
- aliases->aliases[alias->slot].flags |= KVM_ALIAS_INVALID;
- old_aliases = kvm->arch.aliases;
- rcu_assign_pointer(kvm->arch.aliases, aliases);
- synchronize_srcu_expedited(&kvm->srcu);
- kvm_mmu_zap_all(kvm);
- kfree(old_aliases);
-
- r = -ENOMEM;
- aliases = kzalloc(sizeof(struct kvm_mem_aliases), GFP_KERNEL);
- if (!aliases)
- goto out_unlock;
-
- memcpy(aliases, kvm->arch.aliases, sizeof(struct kvm_mem_aliases));
-
- p = &aliases->aliases[alias->slot];
- p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
- p->npages = alias->memory_size >> PAGE_SHIFT;
- p->target_gfn = alias->target_phys_addr >> PAGE_SHIFT;
- p->flags &= ~(KVM_ALIAS_INVALID);
-
- for (n = KVM_ALIAS_SLOTS; n > 0; --n)
- if (aliases->aliases[n - 1].npages)
- break;
- aliases->naliases = n;
-
- old_aliases = kvm->arch.aliases;
- rcu_assign_pointer(kvm->arch.aliases, aliases);
- synchronize_srcu_expedited(&kvm->srcu);
- kfree(old_aliases);
- r = 0;
-
-out_unlock:
- mutex_unlock(&kvm->slots_lock);
-out:
- return r;
-}
-
static int kvm_vm_ioctl_get_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
{
int r;
@@ -3056,7 +2947,6 @@
union {
struct kvm_pit_state ps;
struct kvm_pit_state2 ps2;
- struct kvm_memory_alias alias;
struct kvm_pit_config pit_config;
} u;
@@ -3101,14 +2991,6 @@
case KVM_GET_NR_MMU_PAGES:
r = kvm_vm_ioctl_get_nr_mmu_pages(kvm);
break;
- case KVM_SET_MEMORY_ALIAS:
- r = -EFAULT;
- if (copy_from_user(&u.alias, argp, sizeof(struct kvm_memory_alias)))
- goto out;
- r = kvm_vm_ioctl_set_memory_alias(kvm, &u.alias);
- if (r)
- goto out;
- break;
case KVM_CREATE_IRQCHIP: {
struct kvm_pic *vpic;
@@ -5559,12 +5441,6 @@
if (!kvm)
return ERR_PTR(-ENOMEM);
- kvm->arch.aliases = kzalloc(sizeof(struct kvm_mem_aliases), GFP_KERNEL);
- if (!kvm->arch.aliases) {
- kfree(kvm);
- return ERR_PTR(-ENOMEM);
- }
-
INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
@@ -5622,7 +5498,6 @@
if (kvm->arch.ept_identity_pagetable)
put_page(kvm->arch.ept_identity_pagetable);
cleanup_srcu_struct(&kvm->srcu);
- kfree(kvm->arch.aliases);
kfree(kvm);
}
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index f4b5445..b7a4047 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -65,13 +65,6 @@
return kvm_read_cr0_bits(vcpu, X86_CR0_PG);
}
-static inline struct kvm_mem_aliases *kvm_aliases(struct kvm *kvm)
-{
- return rcu_dereference_check(kvm->arch.aliases,
- srcu_read_lock_held(&kvm->srcu)
- || lockdep_is_held(&kvm->slots_lock));
-}
-
void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);