[PATCH 5.11 117/152] KVM: x86/mmu: Factor out functions to add/remove TDP MMU pages

Greg Kroah-Hartman
2021-04-05T09:21:52Z

From: Ben Gardon <bgardon@google.com>

[ Upstream commit a9442f594147f95307f691cfba0c31e25dc79b9d ]

Move the work of adding and removing TDP MMU pages to/from "secondary"
data structures to helper functions. These functions will be built on in
future commits to enable MMU operations to proceed (mostly) in parallel.

No functional change expected.

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210202185734.1680553-20-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/mmu/tdp_mmu.c | 47 +++++++++++++++++++++++++++++++-------
1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 4a2b8844f00f..bc49a5b90086 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -262,6 +262,39 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
}
}

+/**
+ * tdp_mmu_link_page - Add a new page to the list of pages used by the TDP MMU
+ *
+ * @kvm: kvm instance
+ * @sp: the new page
+ * @account_nx: This page replaces a NX large page and should be marked for
+ * eventual reclaim.
+ */
+static void tdp_mmu_link_page(struct kvm *kvm, struct kvm_mmu_page *sp,
+ bool account_nx)
+{
+ lockdep_assert_held_write(&kvm->mmu_lock);
+
+ list_add(&sp->link, &kvm->arch.tdp_mmu_pages);
+ if (account_nx)
+ account_huge_nx_page(kvm, sp);
+}
+
+/**
+ * tdp_mmu_unlink_page - Remove page from the list of pages used by the TDP MMU
+ *
+ * @kvm: kvm instance
+ * @sp: the page to be removed
+ */
+static void tdp_mmu_unlink_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ lockdep_assert_held_write(&kvm->mmu_lock);
+
+ list_del(&sp->link);
+ if (sp->lpage_disallowed)
+ unaccount_huge_nx_page(kvm, sp);
+}
+
/**
* handle_removed_tdp_mmu_page - handle a pt removed from the TDP structure
*
@@ -281,10 +314,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, u64 *pt)

trace_kvm_mmu_prepare_zap_page(sp);

- list_del(&sp->link);
-
- if (sp->lpage_disallowed)
- unaccount_huge_nx_page(kvm, sp);
+ tdp_mmu_unlink_page(kvm, sp);

for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
old_child_spte = READ_ONCE(*(pt + i));
@@ -706,15 +736,16 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,

if (!is_shadow_present_pte(iter.old_spte)) {
sp = alloc_tdp_mmu_page(vcpu, iter.gfn, iter.level);
- list_add(&sp->link, &vcpu->kvm->arch.tdp_mmu_pages);
child_pt = sp->spt;
+
+ tdp_mmu_link_page(vcpu->kvm, sp,
+ huge_page_disallowed &&
+ req_level >= iter.level);
+
new_spte = make_nonleaf_spte(child_pt,
!shadow_accessed_mask);

trace_kvm_mmu_get_page(sp, true);
- if (huge_page_disallowed && req_level >= iter.level)
- account_huge_nx_page(vcpu->kvm, sp);
-
tdp_mmu_set_spte(vcpu->kvm, &iter, new_spte);
}
}
--
2.30.1