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KVM: Remove memory alias support

Browse source 
As advertised in feature-removal-schedule.txt.  Equivalent support is provided
by overlapping memory regions.

Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity 2010-06-21 11:44:20 +03:00
parent fc34531db3
commit a1f4d39500
13 changed files with 11 additions and 225 deletions
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11
Documentation/feature-removal-schedule.txt
View file

@ -538,17 +538,6 @@ Who: Jan Kiszka <jan.kiszka@web.de>
----------------------------
What: KVM memory aliases support
When: July 2010
Why: Memory aliasing support is used for speeding up guest vga access
through the vga windows.
Modern userspace no longer uses this feature, so it's just bitrotted
code and can be removed with no impact.
Who: Avi Kivity <avi@redhat.com>
----------------------------
What: xtime, wall_to_monotonic
When: 2.6.36+
Files: kernel/time/timekeeping.c include/linux/time.h

12
Documentation/kvm/api.txt
View file

@ -226,17 +226,7 @@ Type: vm ioctl
Parameters: struct kvm_memory_alias (in)
Returns: 0 (success), -1 (error)
struct kvm_memory_alias {
__u32 slot; /* this has a different namespace than memory slots */
__u32 flags;
__u64 guest_phys_addr;
__u64 memory_size;
__u64 target_phys_addr;
};
Defines a guest physical address space region as an alias to another
region. Useful for aliased address, for example the VGA low memory
window. Should not be used with userspace memory.
This ioctl is obsolete and has been removed.
4.9 KVM_RUN

5
arch/ia64/kvm/kvm-ia64.c
View file

@ -1946,11 +1946,6 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
return vcpu->arch.timer_fired;
}
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
return gfn;
}
int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE) ||

5
arch/powerpc/kvm/powerpc.c
View file

@ -36,11 +36,6 @@
#define CREATE_TRACE_POINTS
#include "trace.h"
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
return gfn;
}
int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
{
return !(v->arch.msr & MSR_WE) || !!(v->arch.pending_exceptions);

5
arch/s390/kvm/kvm-s390.c
View file

@ -723,11 +723,6 @@ void kvm_arch_flush_shadow(struct kvm *kvm)
{
}
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
return gfn;
}
static int __init kvm_s390_init(void)
{
int ret;

21
arch/x86/include/asm/kvm_host.h
View file

@ -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 @@ struct kvm_vcpu_arch {
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 @@ void kvm_disable_tdp(void);
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);

17
arch/x86/kvm/mmu.c
View file

@ -434,9 +434,7 @@ static void account_shadowed(struct kvm *kvm, gfn_t gfn)
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 @@ static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
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 @@ static int has_wrprotected_page(struct kvm *kvm,
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 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
/*
* 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 @@ static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
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 @@ static int rmap_write_protect(struct kvm *kvm, u64 gfn)
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 @@ static void rmap_recycle(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
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 @@ static void audit_write_protection(struct kvm_vcpu *vcpu)
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);

3
arch/x86/kvm/paging_tmpl.h
View file

@ -576,7 +576,6 @@ static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
* 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 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
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;

125
arch/x86/kvm/x86.c
View file

@ -2740,115 +2740,6 @@ static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
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 @@ long kvm_arch_vm_ioctl(struct file *filp,
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 @@ long kvm_arch_vm_ioctl(struct file *filp,
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 @@ struct kvm *kvm_arch_create_vm(void)
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 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
if (kvm->arch.ept_identity_pagetable)
put_page(kvm->arch.ept_identity_pagetable);
cleanup_srcu_struct(&kvm->srcu);
kfree(kvm->arch.aliases);
kfree(kvm);
}

7
arch/x86/kvm/x86.h
View file

@ -65,13 +65,6 @@ static inline int is_paging(struct kvm_vcpu *vcpu)
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);

1
include/linux/kvm.h
View file

@ -619,6 +619,7 @@ struct kvm_clock_data {
*/
#define KVM_CREATE_VCPU _IO(KVMIO, 0x41)
#define KVM_GET_DIRTY_LOG _IOW(KVMIO, 0x42, struct kvm_dirty_log)
/* KVM_SET_MEMORY_ALIAS is obsolete: */
#define KVM_SET_MEMORY_ALIAS _IOW(KVMIO, 0x43, struct kvm_memory_alias)
#define KVM_SET_NR_MMU_PAGES _IO(KVMIO, 0x44)
#define KVM_GET_NR_MMU_PAGES _IO(KVMIO, 0x45)

6
include/linux/kvm_host.h
View file

@ -286,8 +286,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
int user_alloc);
void kvm_disable_largepages(void);
void kvm_arch_flush_shadow(struct kvm *kvm);
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
gfn_t unalias_gfn_instantiation(struct kvm *kvm, gfn_t gfn);
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
@ -564,10 +562,6 @@ static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_se
}
#endif
#ifndef KVM_ARCH_HAS_UNALIAS_INSTANTIATION
#define unalias_gfn_instantiation unalias_gfn
#endif
#ifdef CONFIG_HAVE_KVM_IRQCHIP
#define KVM_MAX_IRQ_ROUTES 1024

18
virt/kvm/kvm_main.c
View file

@ -841,7 +841,7 @@ int kvm_is_error_hva(unsigned long addr)
}
EXPORT_SYMBOL_GPL(kvm_is_error_hva);
struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn)
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
int i;
struct kvm_memslots *slots = kvm_memslots(kvm);
@ -855,20 +855,13 @@ struct kvm_memory_slot *gfn_to_memslot_unaliased(struct kvm *kvm, gfn_t gfn)
}
return NULL;
}
EXPORT_SYMBOL_GPL(gfn_to_memslot_unaliased);
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
gfn = unalias_gfn(kvm, gfn);
return gfn_to_memslot_unaliased(kvm, gfn);
}
EXPORT_SYMBOL_GPL(gfn_to_memslot);
int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{
int i;
struct kvm_memslots *slots = kvm_memslots(kvm);
gfn = unalias_gfn_instantiation(kvm, gfn);
for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
struct kvm_memory_slot *memslot = &slots->memslots[i];
@ -913,7 +906,6 @@ int memslot_id(struct kvm *kvm, gfn_t gfn)
struct kvm_memslots *slots = kvm_memslots(kvm);
struct kvm_memory_slot *memslot = NULL;
gfn = unalias_gfn(kvm, gfn);
for (i = 0; i < slots->nmemslots; ++i) {
memslot = &slots->memslots[i];
@ -934,8 +926,7 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
gfn = unalias_gfn_instantiation(kvm, gfn);
slot = gfn_to_memslot_unaliased(kvm, gfn);
slot = gfn_to_memslot(kvm, gfn);
if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
return bad_hva();
return gfn_to_hva_memslot(slot, gfn);
@ -1202,8 +1193,7 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *memslot;
gfn = unalias_gfn(kvm, gfn);
memslot = gfn_to_memslot_unaliased(kvm, gfn);
memslot = gfn_to_memslot(kvm, gfn);
if (memslot && memslot->dirty_bitmap) {
unsigned long rel_gfn = gfn - memslot->base_gfn;