| Message ID | 20220422210546.458943-6-dmatlack@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Extend Eager Page Splitting to the shadow MMU | expand |
On Fri, Apr 22, 2022, David Matlack wrote: > Consolidate kvm_mmu_alloc_page() and kvm_mmu_alloc_shadow_page() under > the latter so that all shadow page allocation and initialization happens > in one place. > > No functional change intended. > > Signed-off-by: David Matlack <dmatlack@google.com> > --- > arch/x86/kvm/mmu/mmu.c | 39 +++++++++++++++++---------------------- > 1 file changed, 17 insertions(+), 22 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 5582badf4947..7d03320f6e08 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -1703,27 +1703,6 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, > mmu_spte_clear_no_track(parent_pte); > } > > -static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, bool direct) > -{ > - struct kvm_mmu_page *sp; > - > - sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); > - sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); > - if (!direct) > - sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); > - set_page_private(virt_to_page(sp->spt), (unsigned long)sp); > - > - /* > - * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() > - * depends on valid pages being added to the head of the list. See > - * comments in kvm_zap_obsolete_pages(). > - */ > - sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; > - list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); > - kvm_mod_used_mmu_pages(vcpu->kvm, +1); > - return sp; > -} > - > static void mark_unsync(u64 *spte); > static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp) > { > @@ -2100,7 +2079,23 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, > struct hlist_head *sp_list, > union kvm_mmu_page_role role) > { > - struct kvm_mmu_page *sp = kvm_mmu_alloc_page(vcpu, role.direct); > + struct kvm_mmu_page *sp; > + > + sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); > + sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); > + if (!role.direct) > + sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); > + > + set_page_private(virt_to_page(sp->spt), (unsigned long)sp); > + > + /* > + * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() > + * depends on valid pages being added to the head of the list. See > + * comments in kvm_zap_obsolete_pages(). > + */ > + sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; > + list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); > + kvm_mod_used_mmu_pages(vcpu->kvm, +1); To reduce churn later on, what about opportunistically grabbing vcpu->kvm in a local variable in this patch? Actually, at that point, it's a super trivial change, so you can probably just drop KVM: x86/mmu: Replace vcpu with kvm in kvm_mmu_alloc_shadow_page() and do the vcpu/kvm swap as part of KVM: x86/mmu: Pass memory caches to allocate SPs separately > sp->gfn = gfn; > sp->role = role; > -- > 2.36.0.rc2.479.g8af0fa9b8e-goog >
On Thu, May 5, 2022 at 3:10 PM Sean Christopherson <seanjc@google.com> wrote: > > On Fri, Apr 22, 2022, David Matlack wrote: > > Consolidate kvm_mmu_alloc_page() and kvm_mmu_alloc_shadow_page() under > > the latter so that all shadow page allocation and initialization happens > > in one place. > > > > No functional change intended. > > > > Signed-off-by: David Matlack <dmatlack@google.com> > > --- > > arch/x86/kvm/mmu/mmu.c | 39 +++++++++++++++++---------------------- > > 1 file changed, 17 insertions(+), 22 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 5582badf4947..7d03320f6e08 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -1703,27 +1703,6 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, > > mmu_spte_clear_no_track(parent_pte); > > } > > > > -static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, bool direct) > > -{ > > - struct kvm_mmu_page *sp; > > - > > - sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); > > - sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); > > - if (!direct) > > - sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); > > - set_page_private(virt_to_page(sp->spt), (unsigned long)sp); > > - > > - /* > > - * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() > > - * depends on valid pages being added to the head of the list. See > > - * comments in kvm_zap_obsolete_pages(). > > - */ > > - sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; > > - list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); > > - kvm_mod_used_mmu_pages(vcpu->kvm, +1); > > - return sp; > > -} > > - > > static void mark_unsync(u64 *spte); > > static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp) > > { > > @@ -2100,7 +2079,23 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, > > struct hlist_head *sp_list, > > union kvm_mmu_page_role role) > > { > > - struct kvm_mmu_page *sp = kvm_mmu_alloc_page(vcpu, role.direct); > > + struct kvm_mmu_page *sp; > > + > > + sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); > > + sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); > > + if (!role.direct) > > + sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); > > + > > + set_page_private(virt_to_page(sp->spt), (unsigned long)sp); > > + > > + /* > > + * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() > > + * depends on valid pages being added to the head of the list. See > > + * comments in kvm_zap_obsolete_pages(). > > + */ > > + sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; > > + list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); > > + kvm_mod_used_mmu_pages(vcpu->kvm, +1); > > To reduce churn later on, what about opportunistically grabbing vcpu->kvm in a > local variable in this patch? > > Actually, at that point, it's a super trivial change, so you can probably just drop > > KVM: x86/mmu: Replace vcpu with kvm in kvm_mmu_alloc_shadow_page() > > and do the vcpu/kvm swap as part of > > KVM: x86/mmu: Pass memory caches to allocate SPs separately I'm not sure it's any less churn, it's just doing the same amount of changes in fewer commits. Is there a benefit of using less commits? I can only think of downsides (harder to review, harder to bisect). > > > sp->gfn = gfn; > > sp->role = role; > > -- > > 2.36.0.rc2.479.g8af0fa9b8e-goog > >
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 5582badf4947..7d03320f6e08 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1703,27 +1703,6 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } -static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, bool direct) -{ - struct kvm_mmu_page *sp; - - sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); - sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); - if (!direct) - sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); - set_page_private(virt_to_page(sp->spt), (unsigned long)sp); - - /* - * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() - * depends on valid pages being added to the head of the list. See - * comments in kvm_zap_obsolete_pages(). - */ - sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; - list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); - kvm_mod_used_mmu_pages(vcpu->kvm, +1); - return sp; -} - static void mark_unsync(u64 *spte); static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp) { @@ -2100,7 +2079,23 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, struct hlist_head *sp_list, union kvm_mmu_page_role role) { - struct kvm_mmu_page *sp = kvm_mmu_alloc_page(vcpu, role.direct); + struct kvm_mmu_page *sp; + + sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); + sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); + if (!role.direct) + sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); + + set_page_private(virt_to_page(sp->spt), (unsigned long)sp); + + /* + * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() + * depends on valid pages being added to the head of the list. See + * comments in kvm_zap_obsolete_pages(). + */ + sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; + list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); + kvm_mod_used_mmu_pages(vcpu->kvm, +1); sp->gfn = gfn; sp->role = role;
Consolidate kvm_mmu_alloc_page() and kvm_mmu_alloc_shadow_page() under the latter so that all shadow page allocation and initialization happens in one place. No functional change intended. Signed-off-by: David Matlack <dmatlack@google.com> --- arch/x86/kvm/mmu/mmu.c | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-)