| Message ID | 20211213225918.672507-7-dmatlack@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86/mmu: Eager Page Splitting for the TDP MMU | expand |
On Mon, Dec 13, 2021 at 10:59:11PM +0000, David Matlack wrote: > Instead of passing a pointer to the root page table and the root level > separately, pass in a pointer to the kvm_mmu_page that backs the root. > This reduces the number of arguments by 1, cutting down on line lengths. > > No functional change intended. > > Signed-off-by: David Matlack <dmatlack@google.com> > Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Peter Xu <peterx@redhat.com>
On Mon, Dec 13, 2021, David Matlack wrote: > Instead of passing a pointer to the root page table and the root level > separately, pass in a pointer to the kvm_mmu_page that backs the root. > This reduces the number of arguments by 1, cutting down on line lengths. > > No functional change intended. > > Signed-off-by: David Matlack <dmatlack@google.com> > Reviewed-by: Ben Gardon <bgardon@google.com> > --- > arch/x86/kvm/mmu/tdp_iter.c | 5 ++++- > arch/x86/kvm/mmu/tdp_iter.h | 10 +++++----- > arch/x86/kvm/mmu/tdp_mmu.c | 14 +++++--------- > 3 files changed, 14 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c > index b3ed302c1a35..92b3a075525a 100644 > --- a/arch/x86/kvm/mmu/tdp_iter.c > +++ b/arch/x86/kvm/mmu/tdp_iter.c > @@ -39,9 +39,12 @@ void tdp_iter_restart(struct tdp_iter *iter) > * Sets a TDP iterator to walk a pre-order traversal of the paging structure > * rooted at root_pt, starting with the walk to translate next_last_level_gfn. > */ > -void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level, > +void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, > int min_level, gfn_t next_last_level_gfn) > { > + u64 *root_pt = root->spt; > + int root_level = root->role.level; Uber nit, arch/x86/ prefers reverse fir tree, though I've yet to get Paolo fully on board :-) But looking at the usage of root_pt, even better would be void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, int min_level, gfn_t next_last_level_gfn) { int root_level = root->role.level; WARN_ON(root_level < 1); WARN_ON(root_level > PT64_ROOT_MAX_LEVEL); iter->next_last_level_gfn = next_last_level_gfn; iter->root_level = root_level; iter->min_level = min_level; iter->pt_path[iter->root_level - 1] = (tdp_ptep_t)root->spt; iter->as_id = kvm_mmu_page_as_id(root); tdp_iter_restart(iter); } to avoid the pointless sptep_to_sp() and eliminate the motivation for root_pt.
On Thu, Jan 6, 2022 at 12:34 PM Sean Christopherson <seanjc@google.com> wrote: > > On Mon, Dec 13, 2021, David Matlack wrote: > > Instead of passing a pointer to the root page table and the root level > > separately, pass in a pointer to the kvm_mmu_page that backs the root. > > This reduces the number of arguments by 1, cutting down on line lengths. > > > > No functional change intended. > > > > Signed-off-by: David Matlack <dmatlack@google.com> > > Reviewed-by: Ben Gardon <bgardon@google.com> > > --- > > arch/x86/kvm/mmu/tdp_iter.c | 5 ++++- > > arch/x86/kvm/mmu/tdp_iter.h | 10 +++++----- > > arch/x86/kvm/mmu/tdp_mmu.c | 14 +++++--------- > > 3 files changed, 14 insertions(+), 15 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c > > index b3ed302c1a35..92b3a075525a 100644 > > --- a/arch/x86/kvm/mmu/tdp_iter.c > > +++ b/arch/x86/kvm/mmu/tdp_iter.c > > @@ -39,9 +39,12 @@ void tdp_iter_restart(struct tdp_iter *iter) > > * Sets a TDP iterator to walk a pre-order traversal of the paging structure > > * rooted at root_pt, starting with the walk to translate next_last_level_gfn. > > */ > > -void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level, > > +void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, > > int min_level, gfn_t next_last_level_gfn) > > { > > + u64 *root_pt = root->spt; > > + int root_level = root->role.level; > > Uber nit, arch/x86/ prefers reverse fir tree, though I've yet to get Paolo fully > on board :-) > > But looking at the usage of root_pt, even better would be > > void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, > int min_level, gfn_t next_last_level_gfn) > { > int root_level = root->role.level; > > WARN_ON(root_level < 1); > WARN_ON(root_level > PT64_ROOT_MAX_LEVEL); > > iter->next_last_level_gfn = next_last_level_gfn; > iter->root_level = root_level; > iter->min_level = min_level; > iter->pt_path[iter->root_level - 1] = (tdp_ptep_t)root->spt; > iter->as_id = kvm_mmu_page_as_id(root); > > tdp_iter_restart(iter); > } > > to avoid the pointless sptep_to_sp() and eliminate the motivation for root_pt. Will do.
diff --git a/arch/x86/kvm/mmu/tdp_iter.c b/arch/x86/kvm/mmu/tdp_iter.c index b3ed302c1a35..92b3a075525a 100644 --- a/arch/x86/kvm/mmu/tdp_iter.c +++ b/arch/x86/kvm/mmu/tdp_iter.c @@ -39,9 +39,12 @@ void tdp_iter_restart(struct tdp_iter *iter) * Sets a TDP iterator to walk a pre-order traversal of the paging structure * rooted at root_pt, starting with the walk to translate next_last_level_gfn. */ -void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level, +void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, int min_level, gfn_t next_last_level_gfn) { + u64 *root_pt = root->spt; + int root_level = root->role.level; + WARN_ON(root_level < 1); WARN_ON(root_level > PT64_ROOT_MAX_LEVEL); diff --git a/arch/x86/kvm/mmu/tdp_iter.h b/arch/x86/kvm/mmu/tdp_iter.h index b1748b988d3a..ec1f58013428 100644 --- a/arch/x86/kvm/mmu/tdp_iter.h +++ b/arch/x86/kvm/mmu/tdp_iter.h @@ -51,17 +51,17 @@ struct tdp_iter { * Iterates over every SPTE mapping the GFN range [start, end) in a * preorder traversal. */ -#define for_each_tdp_pte_min_level(iter, root, root_level, min_level, start, end) \ - for (tdp_iter_start(&iter, root, root_level, min_level, start); \ +#define for_each_tdp_pte_min_level(iter, root, min_level, start, end) \ + for (tdp_iter_start(&iter, root, min_level, start); \ iter.valid && iter.gfn < end; \ tdp_iter_next(&iter)) -#define for_each_tdp_pte(iter, root, root_level, start, end) \ - for_each_tdp_pte_min_level(iter, root, root_level, PG_LEVEL_4K, start, end) +#define for_each_tdp_pte(iter, root, start, end) \ + for_each_tdp_pte_min_level(iter, root, PG_LEVEL_4K, start, end) tdp_ptep_t spte_to_child_pt(u64 pte, int level); -void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level, +void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root, int min_level, gfn_t next_last_level_gfn); void tdp_iter_next(struct tdp_iter *iter); void tdp_iter_restart(struct tdp_iter *iter); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index dbd07c10d11a..2fb2d7677fbf 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -632,7 +632,7 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm, } #define tdp_root_for_each_pte(_iter, _root, _start, _end) \ - for_each_tdp_pte(_iter, _root->spt, _root->role.level, _start, _end) + for_each_tdp_pte(_iter, _root, _start, _end) #define tdp_root_for_each_leaf_pte(_iter, _root, _start, _end) \ tdp_root_for_each_pte(_iter, _root, _start, _end) \ @@ -642,8 +642,7 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm, else #define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \ - for_each_tdp_pte(_iter, __va(_mmu->root_hpa), \ - _mmu->shadow_root_level, _start, _end) + for_each_tdp_pte(_iter, to_shadow_page(_mmu->root_hpa), _start, _end) /* * Yield if the MMU lock is contended or this thread needs to return control @@ -733,8 +732,7 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, rcu_read_lock(); - for_each_tdp_pte_min_level(iter, root->spt, root->role.level, - min_level, start, end) { + for_each_tdp_pte_min_level(iter, root, min_level, start, end) { retry: if (can_yield && tdp_mmu_iter_cond_resched(kvm, &iter, flush, shared)) { @@ -1205,8 +1203,7 @@ static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL); - for_each_tdp_pte_min_level(iter, root->spt, root->role.level, - min_level, start, end) { + for_each_tdp_pte_min_level(iter, root, min_level, start, end) { retry: if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true)) continue; @@ -1445,8 +1442,7 @@ static bool write_protect_gfn(struct kvm *kvm, struct kvm_mmu_page *root, rcu_read_lock(); - for_each_tdp_pte_min_level(iter, root->spt, root->role.level, - min_level, gfn, gfn + 1) { + for_each_tdp_pte_min_level(iter, root, min_level, gfn, gfn + 1) { if (!is_shadow_present_pte(iter.old_spte) || !is_last_spte(iter.old_spte, iter.level)) continue;