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KVM: PPC: Book3S HV: Use the hardware referenced bit for kvm_age_hva

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This uses the host view of the hardware R (referenced) bit to speed
up kvm_age_hva() and kvm_test_age_hva().  Instead of removing all
the relevant HPTEs in kvm_age_hva(), we now just reset their R bits
if set.  Also, kvm_test_age_hva() now scans the relevant HPTEs to
see if any of them have R set.

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 02:02:47 +00:00 committed by Avi Kivity
parent bad3b5075e
commit 5551489373
3 changed files with 91 additions and 11 deletions
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2
arch/powerpc/include/asm/kvm_book3s.h
View File

@ -147,6 +147,8 @@ extern void kvmppc_add_revmap_chain(struct kvm *kvm, struct revmap_entry *rev,
unsigned long *rmap, long pte_index, int realmode);
extern void kvmppc_invalidate_hpte(struct kvm *kvm, unsigned long *hptep,
unsigned long pte_index);
void kvmppc_clear_ref_hpte(struct kvm *kvm, unsigned long *hptep,
unsigned long pte_index);
extern void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long addr,
unsigned long *nb_ret);
extern void kvmppc_unpin_guest_page(struct kvm *kvm, void *addr);

81
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@ -772,16 +772,50 @@ int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long gfn)
{
if (!kvm->arch.using_mmu_notifiers)
return 0;
if (!(*rmapp & KVMPPC_RMAP_REFERENCED))
return 0;
kvm_unmap_rmapp(kvm, rmapp, gfn);
while (test_and_set_bit_lock(KVMPPC_RMAP_LOCK_BIT, rmapp))
cpu_relax();
*rmapp &= ~KVMPPC_RMAP_REFERENCED;
__clear_bit_unlock(KVMPPC_RMAP_LOCK_BIT, rmapp);
return 1;
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_REFERENCED) {
*rmapp &= ~KVMPPC_RMAP_REFERENCED;
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 this HPTE isn't referenced, ignore it */
if (!(hptep[1] & HPTE_R_R))
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_R)) {
kvmppc_clear_ref_hpte(kvm, hptep, i);
rev[i].guest_rpte |= HPTE_R_R;
ret = 1;
}
hptep[0] &= ~HPTE_V_HVLOCK;
} while ((i = j) != head);
unlock_rmap(rmapp);
return ret;
}
int kvm_age_hva(struct kvm *kvm, unsigned long hva)
@ -794,7 +828,32 @@ int kvm_age_hva(struct kvm *kvm, unsigned long hva)
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long gfn)
{
return !!(*rmapp & KVMPPC_RMAP_REFERENCED);
struct revmap_entry *rev = kvm->arch.revmap;
unsigned long head, i, j;
unsigned long *hp;
int ret = 1;
if (*rmapp & KVMPPC_RMAP_REFERENCED)
return 1;
lock_rmap(rmapp);
if (*rmapp & KVMPPC_RMAP_REFERENCED)
goto out;
if (*rmapp & KVMPPC_RMAP_PRESENT) {
i = head = *rmapp & KVMPPC_RMAP_INDEX;
do {
hp = (unsigned long *)(kvm->arch.hpt_virt + (i << 4));
j = rev[i].forw;
if (hp[1] & HPTE_R_R)
goto out;
} while ((i = j) != head);
}
ret = 0;
out:
unlock_rmap(rmapp);
return ret;
}
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)

19
arch/powerpc/kvm/book3s_hv_rm_mmu.c
View File

@ -641,6 +641,25 @@ void kvmppc_invalidate_hpte(struct kvm *kvm, unsigned long *hptep,
}
EXPORT_SYMBOL_GPL(kvmppc_invalidate_hpte);
void kvmppc_clear_ref_hpte(struct kvm *kvm, unsigned long *hptep,
unsigned long pte_index)
{
unsigned long rb;
unsigned char rbyte;
rb = compute_tlbie_rb(hptep[0], hptep[1], pte_index);
rbyte = (hptep[1] & ~HPTE_R_R) >> 8;
/* modify only the second-last byte, which contains the ref bit */
*((char *)hptep + 14) = rbyte;
while (!try_lock_tlbie(&kvm->arch.tlbie_lock))
cpu_relax();
asm volatile(PPC_TLBIE(%1,%0)"; eieio; tlbsync"
: : "r" (rb), "r" (kvm->arch.lpid));
asm volatile("ptesync" : : : "memory");
kvm->arch.tlbie_lock = 0;
}
EXPORT_SYMBOL_GPL(kvmppc_clear_ref_hpte);
static int slb_base_page_shift[4] = {
24, /* 16M */
16, /* 64k */