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KVM: PPC: Book3s HV: Implement get_dirty_log using hardware changed bit

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This changes the implementation of kvm_vm_ioctl_get_dirty_log() for
Book3s HV guests to use the hardware C (changed) bits in the guest
hashed page table.  Since this makes the implementation quite different
from the Book3s PR case, this moves the existing implementation from
book3s.c to book3s_pr.c and creates a new implementation in book3s_hv.c.
That implementation calls kvmppc_hv_get_dirty_log() to do the actual
work by calling kvm_test_clear_dirty on each page.  It iterates over
the HPTEs, clearing the C bit if set, and returns 1 if any C bit was
set (including the saved C bit in the rmap entry).

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Paul Mackerras 2011-12-15 02:03:22 +00:00 committed by Avi Kivity
parent 5551489373
commit 82ed36164c
5 changed files with 147 additions and 39 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/powerpc/include/asm/kvm_book3s.h
View file

@ -156,6 +156,8 @@ extern long kvmppc_virtmode_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel);
extern long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel);
extern long kvmppc_hv_get_dirty_log(struct kvm *kvm,
struct kvm_memory_slot *memslot);
extern void kvmppc_entry_trampoline(void);
extern void kvmppc_hv_entry_trampoline(void);

39
arch/powerpc/kvm/book3s.c
View file

@ -477,45 +477,6 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
return 0;
}
/*
* Get (and clear) the dirty memory log for a memory slot.
*/
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
struct kvm_memory_slot *memslot;
struct kvm_vcpu *vcpu;
ulong ga, ga_end;
int is_dirty = 0;
int r;
unsigned long n;
mutex_lock(&kvm->slots_lock);
r = kvm_get_dirty_log(kvm, log, &is_dirty);
if (r)
goto out;
/* If nothing is dirty, don't bother messing with page tables. */
if (is_dirty) {
memslot = id_to_memslot(kvm->memslots, log->slot);
ga = memslot->base_gfn << PAGE_SHIFT;
ga_end = ga + (memslot->npages << PAGE_SHIFT);
kvm_for_each_vcpu(n, vcpu, kvm)
kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);
n = kvm_dirty_bitmap_bytes(memslot);
memset(memslot->dirty_bitmap, 0, n);
}
r = 0;
out:
mutex_unlock(&kvm->slots_lock);
return r;
}
void kvmppc_decrementer_func(unsigned long data)
{
struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;

69
arch/powerpc/kvm/book3s_64_mmu_hv.c
View file

@ -870,6 +870,75 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
}
static int kvm_test_clear_dirty(struct kvm *kvm, unsigned long *rmapp)
{
struct revmap_entry *rev = kvm->arch.revmap;
unsigned long head, i, j;
unsigned long *hptep;
int ret = 0;
retry:
lock_rmap(rmapp);
if (*rmapp & KVMPPC_RMAP_CHANGED) {
*rmapp &= ~KVMPPC_RMAP_CHANGED;
ret = 1;
}
if (!(*rmapp & KVMPPC_RMAP_PRESENT)) {
unlock_rmap(rmapp);
return ret;
}
i = head = *rmapp & KVMPPC_RMAP_INDEX;
do {
hptep = (unsigned long *) (kvm->arch.hpt_virt + (i << 4));
j = rev[i].forw;
if (!(hptep[1] & HPTE_R_C))
continue;
if (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) {
/* unlock rmap before spinning on the HPTE lock */
unlock_rmap(rmapp);
while (hptep[0] & HPTE_V_HVLOCK)
cpu_relax();
goto retry;
}
/* Now check and modify the HPTE */
if ((hptep[0] & HPTE_V_VALID) && (hptep[1] & HPTE_R_C)) {
/* need to make it temporarily absent to clear C */
hptep[0] |= HPTE_V_ABSENT;
kvmppc_invalidate_hpte(kvm, hptep, i);
hptep[1] &= ~HPTE_R_C;
eieio();
hptep[0] = (hptep[0] & ~HPTE_V_ABSENT) | HPTE_V_VALID;
rev[i].guest_rpte |= HPTE_R_C;
ret = 1;
}
hptep[0] &= ~HPTE_V_HVLOCK;
} while ((i = j) != head);
unlock_rmap(rmapp);
return ret;
}
long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
{
unsigned long i;
unsigned long *rmapp, *map;
preempt_disable();
rmapp = memslot->rmap;
map = memslot->dirty_bitmap;
for (i = 0; i < memslot->npages; ++i) {
if (kvm_test_clear_dirty(kvm, rmapp))
__set_bit_le(i, map);
++rmapp;
}
preempt_enable();
return 0;
}
void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa,
unsigned long *nb_ret)
{

37
arch/powerpc/kvm/book3s_hv.c
View file

@ -1072,6 +1072,43 @@ long kvm_vm_ioctl_allocate_rma(struct kvm *kvm, struct kvm_allocate_rma *ret)
return fd;
}
/*
* Get (and clear) the dirty memory log for a memory slot.
*/
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
{
struct kvm_memory_slot *memslot;
int r;
unsigned long n;
mutex_lock(&kvm->slots_lock);
r = -EINVAL;
if (log->slot >= KVM_MEMORY_SLOTS)
goto out;
memslot = id_to_memslot(kvm->memslots, log->slot);
r = -ENOENT;
if (!memslot->dirty_bitmap)
goto out;
n = kvm_dirty_bitmap_bytes(memslot);
memset(memslot->dirty_bitmap, 0, n);
r = kvmppc_hv_get_dirty_log(kvm, memslot);
if (r)
goto out;
r = -EFAULT;
if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
goto out;
r = 0;
out:
mutex_unlock(&kvm->slots_lock);
return r;
}
static unsigned long slb_pgsize_encoding(unsigned long psize)
{
unsigned long senc = 0;

39
arch/powerpc/kvm/book3s_pr.c
View file

@ -1056,6 +1056,45 @@ out:
return ret;
}
/*
* Get (and clear) the dirty memory log for a memory slot.
*/
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
struct kvm_memory_slot *memslot;
struct kvm_vcpu *vcpu;
ulong ga, ga_end;
int is_dirty = 0;
int r;
unsigned long n;
mutex_lock(&kvm->slots_lock);
r = kvm_get_dirty_log(kvm, log, &is_dirty);
if (r)
goto out;
/* If nothing is dirty, don't bother messing with page tables. */
if (is_dirty) {
memslot = id_to_memslot(kvm->memslots, log->slot);
ga = memslot->base_gfn << PAGE_SHIFT;
ga_end = ga + (memslot->npages << PAGE_SHIFT);
kvm_for_each_vcpu(n, vcpu, kvm)
kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);
n = kvm_dirty_bitmap_bytes(memslot);
memset(memslot->dirty_bitmap, 0, n);
}
r = 0;
out:
mutex_unlock(&kvm->slots_lock);
return r;
}
int kvmppc_core_prepare_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem)
{