[PATCH v7 3/4] KVM: x86/mmu: count KVM mmu usage in secondary pagetable stats.

From: Yosry Ahmed
Date: Mon Aug 22 2022 - 20:47:09 EST


Count the pages used by KVM mmu on x86 in memory stats under secondary
pagetable stats (e.g. "SecPageTables" in /proc/meminfo) to give better
visibility into the memory consumption of KVM mmu in a similar way to
how normal user page tables are accounted.

Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 16 ++++++++++++++--
arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++++
2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e418ef3ecfcb..4d38e4eba772 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1665,6 +1665,18 @@ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr)
percpu_counter_add(&kvm_total_used_mmu_pages, nr);
}

+static void kvm_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ kvm_mod_used_mmu_pages(kvm, +1);
+ kvm_account_pgtable_pages((void *)sp->spt, +1);
+}
+
+static void kvm_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ kvm_mod_used_mmu_pages(kvm, -1);
+ kvm_account_pgtable_pages((void *)sp->spt, -1);
+}
+
static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp)
{
MMU_WARN_ON(!is_empty_shadow_page(sp->spt));
@@ -2122,7 +2134,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm,
*/
sp->mmu_valid_gen = kvm->arch.mmu_valid_gen;
list_add(&sp->link, &kvm->arch.active_mmu_pages);
- kvm_mod_used_mmu_pages(kvm, +1);
+ kvm_account_mmu_page(kvm, sp);

sp->gfn = gfn;
sp->role = role;
@@ -2456,7 +2468,7 @@ static bool __kvm_mmu_prepare_zap_page(struct kvm *kvm,
list_add(&sp->link, invalid_list);
else
list_move(&sp->link, invalid_list);
- kvm_mod_used_mmu_pages(kvm, -1);
+ kvm_unaccount_mmu_page(kvm, sp);
} else {
/*
* Remove the active root from the active page list, the root
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index bf2ccf9debca..672f0432d777 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -372,6 +372,16 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
}
}

+static void tdp_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ kvm_account_pgtable_pages((void *)sp->spt, +1);
+}
+
+static void tdp_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ kvm_account_pgtable_pages((void *)sp->spt, -1);
+}
+
/**
* tdp_mmu_unlink_sp() - Remove a shadow page from the list of used pages
*
@@ -384,6 +394,7 @@ static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
static void tdp_mmu_unlink_sp(struct kvm *kvm, struct kvm_mmu_page *sp,
bool shared)
{
+ tdp_unaccount_mmu_page(kvm, sp);
if (shared)
spin_lock(&kvm->arch.tdp_mmu_pages_lock);
else
@@ -1132,6 +1143,7 @@ static int tdp_mmu_link_sp(struct kvm *kvm, struct tdp_iter *iter,
if (account_nx)
account_huge_nx_page(kvm, sp);
spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
+ tdp_account_mmu_page(kvm, sp);

return 0;
}
--
2.37.1.595.g718a3a8f04-goog