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KVM: x86: MMU: Move parent_pte handling from kvm_mmu_get_page() to link_shadow_page() 

Every time kvm_mmu_get_page() is called with a non-NULL parent_pte
argument, link_shadow_page() follows that to set the parent entry so
that the new mapping will point to the returned page table.

Moving parent_pte handling there allows to clean up the code because
parent_pte is passed to kvm_mmu_get_page() just for mark_unsync() and
mmu_page_add_parent_pte().

In addition, the patch avoids calling mark_unsync() for other parents in
the sp->parent_ptes chain than the newly added parent_pte, because they
have been there since before the current page fault handling started.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Takuya Yoshikawa 2015-11-26 21:14:34 +09:00 committed by Paolo Bonzini
parent 4700579241
commit 98bba23842
2 changed files with 11 additions and 18 deletions
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23
arch/x86/kvm/mmu.c
View File

@ -2119,12 +2119,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
break;
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
if (sp->unsync_children) {
if (sp->unsync_children)
kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
kvm_mmu_mark_parents_unsync(sp);
} else if (sp->unsync)
kvm_mmu_mark_parents_unsync(sp);
__clear_sp_write_flooding_count(sp);
trace_kvm_mmu_get_page(sp, false);
@ -2135,8 +2131,6 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
sp = kvm_mmu_alloc_page(vcpu, direct);
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
sp->gfn = gfn;
sp->role = role;
hlist_add_head(&sp->hash_link,
@ -2204,7 +2198,8 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
return __shadow_walk_next(iterator, *iterator->sptep);
}
static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep,
struct kvm_mmu_page *sp)
{
u64 spte;
@ -2215,6 +2210,11 @@ static void link_shadow_page(u64 *sptep, struct kvm_mmu_page *sp)
shadow_user_mask | shadow_x_mask | shadow_accessed_mask;
mmu_spte_set(sptep, spte);
mmu_page_add_parent_pte(vcpu, sp, sptep);
if (sp->unsync_children || sp->unsync)
mark_unsync(sptep);
}
static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
@ -2273,11 +2273,6 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
mmu_page_zap_pte(kvm, sp, sp->spt + i);
}
static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
{
mmu_page_remove_parent_pte(sp, parent_pte);
}
static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
{
u64 *sptep;
@ -2743,7 +2738,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, int write, int map_writable,
iterator.level - 1,
1, ACC_ALL, iterator.sptep);
link_shadow_page(iterator.sptep, sp);
link_shadow_page(vcpu, iterator.sptep, sp);
}
}
return emulate;

6
arch/x86/kvm/paging_tmpl.h
View File

@ -598,7 +598,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
goto out_gpte_changed;
if (sp)
link_shadow_page(it.sptep, sp);
link_shadow_page(vcpu, it.sptep, sp);
}
for (;
@ -618,7 +618,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
true, direct_access, it.sptep);
link_shadow_page(it.sptep, sp);
link_shadow_page(vcpu, it.sptep, sp);
}
clear_sp_write_flooding_count(it.sptep);
@ -629,8 +629,6 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
return emulate;
out_gpte_changed:
if (sp)
kvm_mmu_put_page(sp, it.sptep);
kvm_release_pfn_clean(pfn);
return 0;
}