linux-kernel - [PATCH] KVM: x86/mmu: move reused pages to the top of active_mmu

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Message-ID: <20260120234115.546590-1-someguy@effective-light.com>
Date: Tue, 20 Jan 2026 18:41:15 -0500
From: Hamza Mahfooz <someguy@...ective-light.com>
To: kvm@...r.kernel.org
Cc: Hamza Mahfooz <someguy@...ective-light.com>,
	Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Thomas Gleixner <tglx@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: x86/mmu: move reused pages to the top of active_mmu_pages

Move reused shadow pages to the head of active_mmu_pages in
__kvm_mmu_get_shadow_page(). This will allow us to move towards more of
a LRU approximation eviction strategy instead of just straight FIFO.

Signed-off-by: Hamza Mahfooz <someguy@...ective-light.com>
---
 arch/x86/kvm/mmu/mmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 02c450686b4a..2fe04e01863d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2395,7 +2395,8 @@ static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm *kvm,
 	if (!sp) {
 		created = true;
 		sp = kvm_mmu_alloc_shadow_page(kvm, caches, gfn, sp_list, role);
-	}
+	} else if (!list_is_head(&sp->link, &kvm->arch.active_mmu_pages))
+		list_move(&sp->link, &kvm->arch.active_mmu_pages);
 
 	trace_kvm_mmu_get_page(sp, created);
 	return sp;
-- 
2.52.0