| Message ID | 20220311002528.2230172-5-dmatlack@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Extend Eager Page Splitting to the shadow MMU | expand |
On Fri, Mar 11, 2022 at 12:25:06AM +0000, David Matlack wrote: > Decompose kvm_mmu_get_page() into separate helper functions to increase > readability and prepare for allocating shadow pages without a vcpu > pointer. > > Specifically, pull the guts of kvm_mmu_get_page() into 3 helper > functions: > > __kvm_mmu_find_shadow_page() - > Walks the page hash checking for any existing mmu pages that match the > given gfn and role. Does not attempt to synchronize the page if it is > unsync. > > kvm_mmu_find_shadow_page() - > Wraps __kvm_mmu_find_shadow_page() and handles syncing if necessary. > > kvm_mmu_new_shadow_page() > Allocates and initializes an entirely new kvm_mmu_page. This currently > requries a vcpu pointer for allocation and looking up the memslot but > that will be removed in a future commit. > > Note, kvm_mmu_new_shadow_page() is temporary and will be removed in a > subsequent commit. The name uses "new" rather than the more typical > "alloc" to avoid clashing with the existing kvm_mmu_alloc_page(). > > No functional change intended. > > Signed-off-by: David Matlack <dmatlack@google.com> Looks good to me, a few nitpicks and questions below. > --- > arch/x86/kvm/mmu/mmu.c | 132 ++++++++++++++++++++++++--------- > arch/x86/kvm/mmu/paging_tmpl.h | 5 +- > arch/x86/kvm/mmu/spte.c | 5 +- > 3 files changed, 101 insertions(+), 41 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 23c2004c6435..80dbfe07c87b 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -2027,16 +2027,25 @@ static void clear_sp_write_flooding_count(u64 *spte) > __clear_sp_write_flooding_count(sptep_to_sp(spte)); > } > > -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, > - union kvm_mmu_page_role role) > +/* > + * Searches for an existing SP for the given gfn and role. Makes no attempt to > + * sync the SP if it is marked unsync. > + * > + * If creating an upper-level page table, zaps unsynced pages for the same > + * gfn and adds them to the invalid_list. It's the callers responsibility > + * to call kvm_mmu_commit_zap_page() on invalid_list. > + */ > +static struct kvm_mmu_page *__kvm_mmu_find_shadow_page(struct kvm *kvm, > + gfn_t gfn, > + union kvm_mmu_page_role role, > + struct list_head *invalid_list) > { > struct hlist_head *sp_list; > struct kvm_mmu_page *sp; > int collisions = 0; > - LIST_HEAD(invalid_list); > > - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; > - for_each_valid_sp(vcpu->kvm, sp, sp_list) { > + sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; > + for_each_valid_sp(kvm, sp, sp_list) { > if (sp->gfn != gfn) { > collisions++; > continue; > @@ -2053,60 +2062,109 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, > * upper-level page will be write-protected. > */ > if (role.level > PG_LEVEL_4K && sp->unsync) > - kvm_mmu_prepare_zap_page(vcpu->kvm, sp, > - &invalid_list); > + kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); > + > continue; > } > > - /* unsync and write-flooding only apply to indirect SPs. */ > - if (sp->role.direct) > - goto trace_get_page; > + /* Write-flooding is only tracked for indirect SPs. */ > + if (!sp->role.direct) > + __clear_sp_write_flooding_count(sp); > > - if (sp->unsync) { > - /* > - * The page is good, but is stale. kvm_sync_page does > - * get the latest guest state, but (unlike mmu_unsync_children) > - * it doesn't write-protect the page or mark it synchronized! > - * This way the validity of the mapping is ensured, but the > - * overhead of write protection is not incurred until the > - * guest invalidates the TLB mapping. This allows multiple > - * SPs for a single gfn to be unsync. > - * > - * If the sync fails, the page is zapped. If so, break > - * in order to rebuild it. > - */ > - if (!kvm_sync_page(vcpu, sp, &invalid_list)) > - break; > + goto out; > + } > > - WARN_ON(!list_empty(&invalid_list)); > - kvm_flush_remote_tlbs(vcpu->kvm); > - } > + sp = NULL; > > - __clear_sp_write_flooding_count(sp); > +out: > + if (collisions > kvm->stat.max_mmu_page_hash_collisions) > + kvm->stat.max_mmu_page_hash_collisions = collisions; > + > + return sp; > +} > > -trace_get_page: > - trace_kvm_mmu_get_page(sp, false); > +/* > + * Looks up an existing SP for the given gfn and role if one exists. The > + * return SP is guaranteed to be synced. > + */ > +static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, > + gfn_t gfn, > + union kvm_mmu_page_role role) > +{ > + struct kvm_mmu_page *sp; > + LIST_HEAD(invalid_list); > + > + sp = __kvm_mmu_find_shadow_page(vcpu->kvm, gfn, role, &invalid_list); > + if (!sp) > goto out; > + > + if (sp->unsync) { > + /* > + * The page is good, but is stale. kvm_sync_page does > + * get the latest guest state, but (unlike mmu_unsync_children) > + * it doesn't write-protect the page or mark it synchronized! > + * This way the validity of the mapping is ensured, but the > + * overhead of write protection is not incurred until the > + * guest invalidates the TLB mapping. This allows multiple > + * SPs for a single gfn to be unsync. > + * > + * If the sync fails, the page is zapped and added to the > + * invalid_list. > + */ > + if (!kvm_sync_page(vcpu, sp, &invalid_list)) { > + sp = NULL; > + goto out; > + } > + > + WARN_ON(!list_empty(&invalid_list)); Not related to this patch because I think it's a pure movement here, however I have a question on why invalid_list is guaranteed to be empty.. I'm thinking the case where when lookup the page we could have already called kvm_mmu_prepare_zap_page() there, then when reach here (which is the kvm_sync_page==true case) invalid_list shouldn't be touched in kvm_sync_page(), so it looks possible that it still contains some page to be commited? > + kvm_flush_remote_tlbs(vcpu->kvm); > } > > +out: I'm wondering whether this "out" can be dropped.. with something like: sp = __kvm_mmu_find_shadow_page(...); if (sp && sp->unsync) { if (kvm_sync_page(vcpu, sp, &invalid_list)) { .. } else { sp = NULL; } } [...] > +static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, > + union kvm_mmu_page_role role) > +{ > + struct kvm_mmu_page *sp; > + bool created = false; > + > + sp = kvm_mmu_find_shadow_page(vcpu, gfn, role); > + if (sp) > + goto out; > + > + created = true; > + sp = kvm_mmu_new_shadow_page(vcpu, gfn, role); > + > +out: > + trace_kvm_mmu_get_page(sp, created); > return sp; Same here, wondering whether we could drop the "out" by: sp = kvm_mmu_find_shadow_page(vcpu, gfn, role); if (!sp) { created = true; sp = kvm_mmu_new_shadow_page(vcpu, gfn, role); } trace_kvm_mmu_get_page(sp, created); return sp; Thanks,
On Tue, Mar 15, 2022 at 1:51 AM Peter Xu <peterx@redhat.com> wrote: > > On Fri, Mar 11, 2022 at 12:25:06AM +0000, David Matlack wrote: > > Decompose kvm_mmu_get_page() into separate helper functions to increase > > readability and prepare for allocating shadow pages without a vcpu > > pointer. > > > > Specifically, pull the guts of kvm_mmu_get_page() into 3 helper > > functions: > > > > __kvm_mmu_find_shadow_page() - > > Walks the page hash checking for any existing mmu pages that match the > > given gfn and role. Does not attempt to synchronize the page if it is > > unsync. > > > > kvm_mmu_find_shadow_page() - > > Wraps __kvm_mmu_find_shadow_page() and handles syncing if necessary. > > > > kvm_mmu_new_shadow_page() > > Allocates and initializes an entirely new kvm_mmu_page. This currently > > requries a vcpu pointer for allocation and looking up the memslot but > > that will be removed in a future commit. > > > > Note, kvm_mmu_new_shadow_page() is temporary and will be removed in a > > subsequent commit. The name uses "new" rather than the more typical > > "alloc" to avoid clashing with the existing kvm_mmu_alloc_page(). > > > > No functional change intended. > > > > Signed-off-by: David Matlack <dmatlack@google.com> > > Looks good to me, a few nitpicks and questions below. > > > --- > > arch/x86/kvm/mmu/mmu.c | 132 ++++++++++++++++++++++++--------- > > arch/x86/kvm/mmu/paging_tmpl.h | 5 +- > > arch/x86/kvm/mmu/spte.c | 5 +- > > 3 files changed, 101 insertions(+), 41 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 23c2004c6435..80dbfe07c87b 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -2027,16 +2027,25 @@ static void clear_sp_write_flooding_count(u64 *spte) > > __clear_sp_write_flooding_count(sptep_to_sp(spte)); > > } > > > > -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, > > - union kvm_mmu_page_role role) > > +/* > > + * Searches for an existing SP for the given gfn and role. Makes no attempt to > > + * sync the SP if it is marked unsync. > > + * > > + * If creating an upper-level page table, zaps unsynced pages for the same > > + * gfn and adds them to the invalid_list. It's the callers responsibility > > + * to call kvm_mmu_commit_zap_page() on invalid_list. > > + */ > > +static struct kvm_mmu_page *__kvm_mmu_find_shadow_page(struct kvm *kvm, > > + gfn_t gfn, > > + union kvm_mmu_page_role role, > > + struct list_head *invalid_list) > > { > > struct hlist_head *sp_list; > > struct kvm_mmu_page *sp; > > int collisions = 0; > > - LIST_HEAD(invalid_list); > > > > - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; > > - for_each_valid_sp(vcpu->kvm, sp, sp_list) { > > + sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; > > + for_each_valid_sp(kvm, sp, sp_list) { > > if (sp->gfn != gfn) { > > collisions++; > > continue; > > @@ -2053,60 +2062,109 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, > > * upper-level page will be write-protected. > > */ > > if (role.level > PG_LEVEL_4K && sp->unsync) > > - kvm_mmu_prepare_zap_page(vcpu->kvm, sp, > > - &invalid_list); > > + kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); > > + > > continue; > > } > > > > - /* unsync and write-flooding only apply to indirect SPs. */ > > - if (sp->role.direct) > > - goto trace_get_page; > > + /* Write-flooding is only tracked for indirect SPs. */ > > + if (!sp->role.direct) > > + __clear_sp_write_flooding_count(sp); > > > > - if (sp->unsync) { > > - /* > > - * The page is good, but is stale. kvm_sync_page does > > - * get the latest guest state, but (unlike mmu_unsync_children) > > - * it doesn't write-protect the page or mark it synchronized! > > - * This way the validity of the mapping is ensured, but the > > - * overhead of write protection is not incurred until the > > - * guest invalidates the TLB mapping. This allows multiple > > - * SPs for a single gfn to be unsync. > > - * > > - * If the sync fails, the page is zapped. If so, break > > - * in order to rebuild it. > > - */ > > - if (!kvm_sync_page(vcpu, sp, &invalid_list)) > > - break; > > + goto out; > > + } > > > > - WARN_ON(!list_empty(&invalid_list)); > > - kvm_flush_remote_tlbs(vcpu->kvm); > > - } > > + sp = NULL; > > > > - __clear_sp_write_flooding_count(sp); > > +out: > > + if (collisions > kvm->stat.max_mmu_page_hash_collisions) > > + kvm->stat.max_mmu_page_hash_collisions = collisions; > > + > > + return sp; > > +} > > > > -trace_get_page: > > - trace_kvm_mmu_get_page(sp, false); > > +/* > > + * Looks up an existing SP for the given gfn and role if one exists. The > > + * return SP is guaranteed to be synced. > > + */ > > +static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, > > + gfn_t gfn, > > + union kvm_mmu_page_role role) > > +{ > > + struct kvm_mmu_page *sp; > > + LIST_HEAD(invalid_list); > > + > > + sp = __kvm_mmu_find_shadow_page(vcpu->kvm, gfn, role, &invalid_list); > > + if (!sp) > > goto out; > > + > > + if (sp->unsync) { > > + /* > > + * The page is good, but is stale. kvm_sync_page does > > + * get the latest guest state, but (unlike mmu_unsync_children) > > + * it doesn't write-protect the page or mark it synchronized! > > + * This way the validity of the mapping is ensured, but the > > + * overhead of write protection is not incurred until the > > + * guest invalidates the TLB mapping. This allows multiple > > + * SPs for a single gfn to be unsync. > > + * > > + * If the sync fails, the page is zapped and added to the > > + * invalid_list. > > + */ > > + if (!kvm_sync_page(vcpu, sp, &invalid_list)) { > > + sp = NULL; > > + goto out; > > + } > > + > > + WARN_ON(!list_empty(&invalid_list)); > > Not related to this patch because I think it's a pure movement here, > however I have a question on why invalid_list is guaranteed to be empty.. > > I'm thinking the case where when lookup the page we could have already > called kvm_mmu_prepare_zap_page() there, then when reach here (which is the > kvm_sync_page==true case) invalid_list shouldn't be touched in > kvm_sync_page(), so it looks possible that it still contains some page to > be commited? I also had this question when I was re-organizing this code but haven't had the time to look into it yet. > > > + kvm_flush_remote_tlbs(vcpu->kvm); > > } > > > > +out: > > I'm wondering whether this "out" can be dropped.. with something like: > > sp = __kvm_mmu_find_shadow_page(...); > > if (sp && sp->unsync) { > if (kvm_sync_page(vcpu, sp, &invalid_list)) { > .. > } else { > sp = NULL; > } > } Sure will do. I used the goto to reduce the amount of indentation, but I can definitely get rid of it. > > [...] > > > +static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, > > + union kvm_mmu_page_role role) > > +{ > > + struct kvm_mmu_page *sp; > > + bool created = false; > > + > > + sp = kvm_mmu_find_shadow_page(vcpu, gfn, role); > > + if (sp) > > + goto out; > > + > > + created = true; > > + sp = kvm_mmu_new_shadow_page(vcpu, gfn, role); > > + > > +out: > > + trace_kvm_mmu_get_page(sp, created); > > return sp; > > Same here, wondering whether we could drop the "out" by: > > sp = kvm_mmu_find_shadow_page(vcpu, gfn, role); > if (!sp) { > created = true; > sp = kvm_mmu_new_shadow_page(vcpu, gfn, role); > } > > trace_kvm_mmu_get_page(sp, created); > return sp; Ditto. > > Thanks, > > -- > Peter Xu >
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 23c2004c6435..80dbfe07c87b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2027,16 +2027,25 @@ static void clear_sp_write_flooding_count(u64 *spte) __clear_sp_write_flooding_count(sptep_to_sp(spte)); } -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, - union kvm_mmu_page_role role) +/* + * Searches for an existing SP for the given gfn and role. Makes no attempt to + * sync the SP if it is marked unsync. + * + * If creating an upper-level page table, zaps unsynced pages for the same + * gfn and adds them to the invalid_list. It's the callers responsibility + * to call kvm_mmu_commit_zap_page() on invalid_list. + */ +static struct kvm_mmu_page *__kvm_mmu_find_shadow_page(struct kvm *kvm, + gfn_t gfn, + union kvm_mmu_page_role role, + struct list_head *invalid_list) { struct hlist_head *sp_list; struct kvm_mmu_page *sp; int collisions = 0; - LIST_HEAD(invalid_list); - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; - for_each_valid_sp(vcpu->kvm, sp, sp_list) { + sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; + for_each_valid_sp(kvm, sp, sp_list) { if (sp->gfn != gfn) { collisions++; continue; @@ -2053,60 +2062,109 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, * upper-level page will be write-protected. */ if (role.level > PG_LEVEL_4K && sp->unsync) - kvm_mmu_prepare_zap_page(vcpu->kvm, sp, - &invalid_list); + kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); + continue; } - /* unsync and write-flooding only apply to indirect SPs. */ - if (sp->role.direct) - goto trace_get_page; + /* Write-flooding is only tracked for indirect SPs. */ + if (!sp->role.direct) + __clear_sp_write_flooding_count(sp); - if (sp->unsync) { - /* - * The page is good, but is stale. kvm_sync_page does - * get the latest guest state, but (unlike mmu_unsync_children) - * it doesn't write-protect the page or mark it synchronized! - * This way the validity of the mapping is ensured, but the - * overhead of write protection is not incurred until the - * guest invalidates the TLB mapping. This allows multiple - * SPs for a single gfn to be unsync. - * - * If the sync fails, the page is zapped. If so, break - * in order to rebuild it. - */ - if (!kvm_sync_page(vcpu, sp, &invalid_list)) - break; + goto out; + } - WARN_ON(!list_empty(&invalid_list)); - kvm_flush_remote_tlbs(vcpu->kvm); - } + sp = NULL; - __clear_sp_write_flooding_count(sp); +out: + if (collisions > kvm->stat.max_mmu_page_hash_collisions) + kvm->stat.max_mmu_page_hash_collisions = collisions; + + return sp; +} -trace_get_page: - trace_kvm_mmu_get_page(sp, false); +/* + * Looks up an existing SP for the given gfn and role if one exists. The + * return SP is guaranteed to be synced. + */ +static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct kvm_mmu_page *sp; + LIST_HEAD(invalid_list); + + sp = __kvm_mmu_find_shadow_page(vcpu->kvm, gfn, role, &invalid_list); + if (!sp) goto out; + + if (sp->unsync) { + /* + * The page is good, but is stale. kvm_sync_page does + * get the latest guest state, but (unlike mmu_unsync_children) + * it doesn't write-protect the page or mark it synchronized! + * This way the validity of the mapping is ensured, but the + * overhead of write protection is not incurred until the + * guest invalidates the TLB mapping. This allows multiple + * SPs for a single gfn to be unsync. + * + * If the sync fails, the page is zapped and added to the + * invalid_list. + */ + if (!kvm_sync_page(vcpu, sp, &invalid_list)) { + sp = NULL; + goto out; + } + + WARN_ON(!list_empty(&invalid_list)); + kvm_flush_remote_tlbs(vcpu->kvm); } +out: + kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); + return sp; +} + +static struct kvm_mmu_page *kvm_mmu_new_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct kvm_mmu_page *sp; + struct hlist_head *sp_list; + ++vcpu->kvm->stat.mmu_cache_miss; sp = kvm_mmu_alloc_page(vcpu, role.direct); - sp->gfn = gfn; sp->role = role; + + sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; hlist_add_head(&sp->hash_link, sp_list); + if (!role.direct) { account_shadowed(vcpu->kvm, sp); if (role.level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn)) kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1); } - trace_kvm_mmu_get_page(sp, true); -out: - kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); - if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions) - vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions; + return sp; +} + +static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct kvm_mmu_page *sp; + bool created = false; + + sp = kvm_mmu_find_shadow_page(vcpu, gfn, role); + if (sp) + goto out; + + created = true; + sp = kvm_mmu_new_shadow_page(vcpu, gfn, role); + +out: + trace_kvm_mmu_get_page(sp, created); return sp; } diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index c3909a07e938..55cac59b9c9b 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -692,8 +692,9 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, * the gpte is changed from non-present to present. * Otherwise, the guest may use the wrong mapping. * - * For PG_LEVEL_4K, kvm_mmu_get_page() has already - * synchronized it transiently via kvm_sync_page(). + * For PG_LEVEL_4K, kvm_mmu_get_existing_sp() has + * already synchronized it transiently via + * kvm_sync_page(). * * For higher level pagetable, we synchronize it via * the slower mmu_sync_children(). If it needs to diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 4739b53c9734..d10189d9c877 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -150,8 +150,9 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, /* * Optimization: for pte sync, if spte was writable the hash * lookup is unnecessary (and expensive). Write protection - * is responsibility of kvm_mmu_get_page / kvm_mmu_sync_roots. - * Same reasoning can be applied to dirty page accounting. + * is responsibility of kvm_mmu_create_sp() and + * kvm_mmu_sync_roots(). Same reasoning can be applied to dirty + * page accounting. */ if (is_writable_pte(old_spte)) goto out;
Decompose kvm_mmu_get_page() into separate helper functions to increase readability and prepare for allocating shadow pages without a vcpu pointer. Specifically, pull the guts of kvm_mmu_get_page() into 3 helper functions: __kvm_mmu_find_shadow_page() - Walks the page hash checking for any existing mmu pages that match the given gfn and role. Does not attempt to synchronize the page if it is unsync. kvm_mmu_find_shadow_page() - Wraps __kvm_mmu_find_shadow_page() and handles syncing if necessary. kvm_mmu_new_shadow_page() Allocates and initializes an entirely new kvm_mmu_page. This currently requries a vcpu pointer for allocation and looking up the memslot but that will be removed in a future commit. Note, kvm_mmu_new_shadow_page() is temporary and will be removed in a subsequent commit. The name uses "new" rather than the more typical "alloc" to avoid clashing with the existing kvm_mmu_alloc_page(). No functional change intended. Signed-off-by: David Matlack <dmatlack@google.com> --- arch/x86/kvm/mmu/mmu.c | 132 ++++++++++++++++++++++++--------- arch/x86/kvm/mmu/paging_tmpl.h | 5 +- arch/x86/kvm/mmu/spte.c | 5 +- 3 files changed, 101 insertions(+), 41 deletions(-)