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Merge branch 'kvm-updates-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm

Browse Source 
* 'kvm-updates-2.6.27' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
  KVM: s390: Fix kvm on IBM System z10
  KVM: Advertise synchronized mmu support to userspace
  KVM: Synchronize guest physical memory map to host virtual memory map
  KVM: Allow browsing memslots with mmu_lock
  KVM: Allow reading aliases with mmu_lock
This commit is contained in:
Linus Torvalds 2008-08-01 12:48:16 -07:00
commit 84ff7a0012
8 changed files with 312 additions and 11 deletions
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1
arch/s390/kvm/priv.c
View File

@ -158,6 +158,7 @@ static int handle_stfl(struct kvm_vcpu *vcpu)
vcpu->stat.instruction_stfl++;
facility_list &= ~(1UL<<24); /* no stfle */
facility_list &= ~(1UL<<23); /* no large pages */
rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
&facility_list, sizeof(facility_list));

100
arch/x86/kvm/mmu.c
View File

@ -653,6 +653,84 @@ static void rmap_write_protect(struct kvm *kvm, u64 gfn)
account_shadowed(kvm, gfn);
}
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
{
u64 *spte;
int need_tlb_flush = 0;
while ((spte = rmap_next(kvm, rmapp, NULL))) {
BUG_ON(!(*spte & PT_PRESENT_MASK));
rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
rmap_remove(kvm, spte);
set_shadow_pte(spte, shadow_trap_nonpresent_pte);
need_tlb_flush = 1;
}
return need_tlb_flush;
}
static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
int (*handler)(struct kvm *kvm, unsigned long *rmapp))
{
int i;
int retval = 0;
/*
* If mmap_sem isn't taken, we can look the memslots with only
* the mmu_lock by skipping over the slots with userspace_addr == 0.
*/
for (i = 0; i < kvm->nmemslots; i++) {
struct kvm_memory_slot *memslot = &kvm->memslots[i];
unsigned long start = memslot->userspace_addr;
unsigned long end;
/* mmu_lock protects userspace_addr */
if (!start)
continue;
end = start + (memslot->npages << PAGE_SHIFT);
if (hva >= start && hva < end) {
gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
retval |= handler(kvm, &memslot->rmap[gfn_offset]);
retval |= handler(kvm,
&memslot->lpage_info[
gfn_offset /
KVM_PAGES_PER_HPAGE].rmap_pde);
}
}
return retval;
}
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
}
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
{
u64 *spte;
int young = 0;
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
int _young;
u64 _spte = *spte;
BUG_ON(!(_spte & PT_PRESENT_MASK));
_young = _spte & PT_ACCESSED_MASK;
if (_young) {
young = 1;
clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
}
spte = rmap_next(kvm, rmapp, spte);
}
return young;
}
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
}
#ifdef MMU_DEBUG
static int is_empty_shadow_page(u64 *spt)
{
@ -1203,6 +1281,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
int r;
int largepage = 0;
pfn_t pfn;
unsigned long mmu_seq;
down_read(&current->mm->mmap_sem);
if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
@ -1210,6 +1289,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
largepage = 1;
}
mmu_seq = vcpu->kvm->mmu_notifier_seq;
/* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);
@ -1220,6 +1301,8 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
}
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, v, write, largepage, gfn, pfn,
PT32E_ROOT_LEVEL);
@ -1227,6 +1310,11 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
@ -1345,6 +1433,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
int r;
int largepage = 0;
gfn_t gfn = gpa >> PAGE_SHIFT;
unsigned long mmu_seq;
ASSERT(vcpu);
ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
@ -1358,6 +1447,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
gfn &= ~(KVM_PAGES_PER_HPAGE-1);
largepage = 1;
}
mmu_seq = vcpu->kvm->mmu_notifier_seq;
/* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);
if (is_error_pfn(pfn)) {
@ -1365,12 +1456,19 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
return 1;
}
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
largepage, gfn, pfn, kvm_x86_ops->get_tdp_level());
spin_unlock(&vcpu->kvm->mmu_lock);
return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static void nonpaging_free(struct kvm_vcpu *vcpu)
@ -1670,6 +1768,8 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
gfn &= ~(KVM_PAGES_PER_HPAGE-1);
vcpu->arch.update_pte.largepage = 1;
}
vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
/* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, gfn);
up_read(&current->mm->mmap_sem);

12
arch/x86/kvm/paging_tmpl.h
View File

@ -263,6 +263,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page,
pfn = vcpu->arch.update_pte.pfn;
if (is_error_pfn(pfn))
return;
if (mmu_notifier_retry(vcpu, vcpu->arch.update_pte.mmu_seq))
return;
kvm_get_pfn(pfn);
mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0,
gpte & PT_DIRTY_MASK, NULL, largepage, gpte_to_gfn(gpte),
@ -380,6 +382,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
int r;
pfn_t pfn;
int largepage = 0;
unsigned long mmu_seq;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
kvm_mmu_audit(vcpu, "pre page fault");
@ -413,6 +416,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
largepage = 1;
}
}
mmu_seq = vcpu->kvm->mmu_notifier_seq;
/* implicit mb(), we'll read before PT lock is unlocked */
pfn = gfn_to_pfn(vcpu->kvm, walker.gfn);
up_read(&current->mm->mmap_sem);
@ -424,6 +429,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
}
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu, mmu_seq))
goto out_unlock;
kvm_mmu_free_some_pages(vcpu);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
largepage, &write_pt, pfn);
@ -439,6 +446,11 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
spin_unlock(&vcpu->kvm->mmu_lock);
return write_pt;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)

24
arch/x86/kvm/x86.c
View File

@ -883,6 +883,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_PIT:
case KVM_CAP_NOP_IO_DELAY:
case KVM_CAP_MP_STATE:
case KVM_CAP_SYNC_MMU:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
@ -1495,6 +1496,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
goto out;
down_write(&kvm->slots_lock);
spin_lock(&kvm->mmu_lock);
p = &kvm->arch.aliases[alias->slot];
p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
@ -1506,6 +1508,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
break;
kvm->arch.naliases = n;
spin_unlock(&kvm->mmu_lock);
kvm_mmu_zap_all(kvm);
up_write(&kvm->slots_lock);
@ -3972,16 +3975,23 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
*/
if (!user_alloc) {
if (npages && !old.rmap) {
unsigned long userspace_addr;
down_write(&current->mm->mmap_sem);
memslot->userspace_addr = do_mmap(NULL, 0,
npages * PAGE_SIZE,
PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS,
0);
userspace_addr = do_mmap(NULL, 0,
npages * PAGE_SIZE,
PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS,
0);
up_write(&current->mm->mmap_sem);
if (IS_ERR((void *)memslot->userspace_addr))
return PTR_ERR((void *)memslot->userspace_addr);
if (IS_ERR((void *)userspace_addr))
return PTR_ERR((void *)userspace_addr);
/* set userspace_addr atomically for kvm_hva_to_rmapp */
spin_lock(&kvm->mmu_lock);
memslot->userspace_addr = userspace_addr;
spin_unlock(&kvm->mmu_lock);
} else {
if (!old.user_alloc && old.rmap) {
int ret;

6
include/asm-x86/kvm_host.h
View File

@ -13,6 +13,7 @@
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/mmu_notifier.h>
#include <linux/kvm.h>
#include <linux/kvm_para.h>
@ -251,6 +252,7 @@ struct kvm_vcpu_arch {
gfn_t gfn; /* presumed gfn during guest pte update */
pfn_t pfn; /* pfn corresponding to that gfn */
int largepage;
unsigned long mmu_seq;
} update_pte;
struct i387_fxsave_struct host_fx_image;
@ -729,4 +731,8 @@ asmlinkage void kvm_handle_fault_on_reboot(void);
KVM_EX_ENTRY " 666b, 667b \n\t" \
".popsection"
#define KVM_ARCH_WANT_MMU_NOTIFIER
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
int kvm_age_hva(struct kvm *kvm, unsigned long hva);
#endif

1
include/linux/kvm.h
View File

@ -371,6 +371,7 @@ struct kvm_trace_rec {
#define KVM_CAP_PV_MMU 13
#define KVM_CAP_MP_STATE 14
#define KVM_CAP_COALESCED_MMIO 15
#define KVM_CAP_SYNC_MMU 16 /* Changes to host mmap are reflected in guest */
/*
* ioctls for VM fds

24
include/linux/kvm_host.h
View File

@ -121,6 +121,12 @@ struct kvm {
struct kvm_coalesced_mmio_dev *coalesced_mmio_dev;
struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
#endif
#ifdef KVM_ARCH_WANT_MMU_NOTIFIER
struct mmu_notifier mmu_notifier;
unsigned long mmu_notifier_seq;
long mmu_notifier_count;
#endif
};
/* The guest did something we don't support. */
@ -332,4 +338,22 @@ int kvm_trace_ioctl(unsigned int ioctl, unsigned long arg)
#define kvm_trace_cleanup() ((void)0)
#endif
#ifdef KVM_ARCH_WANT_MMU_NOTIFIER
static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_seq)
{
if (unlikely(vcpu->kvm->mmu_notifier_count))
return 1;
/*
* Both reads happen under the mmu_lock and both values are
* modified under mmu_lock, so there's no need of smb_rmb()
* here in between, otherwise mmu_notifier_count should be
* read before mmu_notifier_seq, see
* mmu_notifier_invalidate_range_end write side.
*/
if (vcpu->kvm->mmu_notifier_seq != mmu_seq)
return 1;
return 0;
}
#endif
#endif

155
virt/kvm/kvm_main.c
View File

@ -192,6 +192,123 @@ void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_vcpu_uninit);
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
{
return container_of(mn, struct kvm, mmu_notifier);
}
static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long address)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int need_tlb_flush;
/*
* When ->invalidate_page runs, the linux pte has been zapped
* already but the page is still allocated until
* ->invalidate_page returns. So if we increase the sequence
* here the kvm page fault will notice if the spte can't be
* established because the page is going to be freed. If
* instead the kvm page fault establishes the spte before
* ->invalidate_page runs, kvm_unmap_hva will release it
* before returning.
*
* The sequence increase only need to be seen at spin_unlock
* time, and not at spin_lock time.
*
* Increasing the sequence after the spin_unlock would be
* unsafe because the kvm page fault could then establish the
* pte after kvm_unmap_hva returned, without noticing the page
* is going to be freed.
*/
spin_lock(&kvm->mmu_lock);
kvm->mmu_notifier_seq++;
need_tlb_flush = kvm_unmap_hva(kvm, address);
spin_unlock(&kvm->mmu_lock);
/* we've to flush the tlb before the pages can be freed */
if (need_tlb_flush)
kvm_flush_remote_tlbs(kvm);
}
static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int need_tlb_flush = 0;
spin_lock(&kvm->mmu_lock);
/*
* The count increase must become visible at unlock time as no
* spte can be established without taking the mmu_lock and
* count is also read inside the mmu_lock critical section.
*/
kvm->mmu_notifier_count++;
for (; start < end; start += PAGE_SIZE)
need_tlb_flush |= kvm_unmap_hva(kvm, start);
spin_unlock(&kvm->mmu_lock);
/* we've to flush the tlb before the pages can be freed */
if (need_tlb_flush)
kvm_flush_remote_tlbs(kvm);
}
static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
spin_lock(&kvm->mmu_lock);
/*
* This sequence increase will notify the kvm page fault that
* the page that is going to be mapped in the spte could have
* been freed.
*/
kvm->mmu_notifier_seq++;
/*
* The above sequence increase must be visible before the
* below count decrease but both values are read by the kvm
* page fault under mmu_lock spinlock so we don't need to add
* a smb_wmb() here in between the two.
*/
kvm->mmu_notifier_count--;
spin_unlock(&kvm->mmu_lock);
BUG_ON(kvm->mmu_notifier_count < 0);
}
static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long address)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int young;
spin_lock(&kvm->mmu_lock);
young = kvm_age_hva(kvm, address);
spin_unlock(&kvm->mmu_lock);
if (young)
kvm_flush_remote_tlbs(kvm);
return young;
}
static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
.invalidate_page = kvm_mmu_notifier_invalidate_page,
.invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
.invalidate_range_end = kvm_mmu_notifier_invalidate_range_end,
.clear_flush_young = kvm_mmu_notifier_clear_flush_young,
};
#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
static struct kvm *kvm_create_vm(void)
{
struct kvm *kvm = kvm_arch_create_vm();
@ -212,6 +329,21 @@ static struct kvm *kvm_create_vm(void)
(struct kvm_coalesced_mmio_ring *)page_address(page);
#endif
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
{
int err;
kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
err = mmu_notifier_register(&kvm->mmu_notifier, current->mm);
if (err) {
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
put_page(page);
#endif
kfree(kvm);
return ERR_PTR(err);
}
}
#endif
kvm->mm = current->mm;
atomic_inc(&kvm->mm->mm_count);
spin_lock_init(&kvm->mmu_lock);
@ -271,6 +403,9 @@ static void kvm_destroy_vm(struct kvm *kvm)
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
if (kvm->coalesced_mmio_ring != NULL)
free_page((unsigned long)kvm->coalesced_mmio_ring);
#endif
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
#endif
kvm_arch_destroy_vm(kvm);
mmdrop(mm);
@ -375,7 +510,15 @@ int __kvm_set_memory_region(struct kvm *kvm,
memset(new.rmap, 0, npages * sizeof(*new.rmap));
new.user_alloc = user_alloc;
new.userspace_addr = mem->userspace_addr;
/*
* hva_to_rmmap() serialzies with the mmu_lock and to be
* safe it has to ignore memslots with !user_alloc &&
* !userspace_addr.
*/
if (user_alloc)
new.userspace_addr = mem->userspace_addr;
else
new.userspace_addr = 0;
}
if (npages && !new.lpage_info) {
int largepages = npages / KVM_PAGES_PER_HPAGE;
@ -408,17 +551,21 @@ int __kvm_set_memory_region(struct kvm *kvm,
}
#endif /* not defined CONFIG_S390 */
if (mem->slot >= kvm->nmemslots)
kvm->nmemslots = mem->slot + 1;
if (!npages)
kvm_arch_flush_shadow(kvm);
spin_lock(&kvm->mmu_lock);
if (mem->slot >= kvm->nmemslots)
kvm->nmemslots = mem->slot + 1;
*memslot = new;
spin_unlock(&kvm->mmu_lock);
r = kvm_arch_set_memory_region(kvm, mem, old, user_alloc);
if (r) {
spin_lock(&kvm->mmu_lock);
*memslot = old;
spin_unlock(&kvm->mmu_lock);
goto out_free;
}