linux-kernel - [PATCH v2 14/15] KVM: x86/tdp_mmu: Invalidate correct roots

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Date: Thu, 30 May 2024 14:07:13 -0700
From: Rick Edgecombe <rick.p.edgecombe@...el.com>
To: seanjc@...gle.com,
	pbonzini@...hat.com,
	kvm@...r.kernel.org
Cc: kai.huang@...el.com,
	dmatlack@...gle.com,
	erdemaktas@...gle.com,
	isaku.yamahata@...il.com,
	linux-kernel@...r.kernel.org,
	sagis@...gle.com,
	yan.y.zhao@...el.com,
	rick.p.edgecombe@...el.com,
	Sean Christopherson <sean.j.christopherson@...el.com>,
	Isaku Yamahata <isaku.yamahata@...el.com>
Subject: [PATCH v2 14/15] KVM: x86/tdp_mmu: Invalidate correct roots

From: Sean Christopherson <sean.j.christopherson@...el.com>

When invalidating roots, respect the root type passed.

kvm_tdp_mmu_invalidate_roots() is called with different root types. For
kvm_mmu_zap_all_fast() it only operates on shared roots. But when tearing
down a VM it needs to invalidate all roots. Check the root type in root
iterator.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Co-developed-by: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
[evolved quite a bit from original author's patch]
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
---
TDX MMU Prep:
 - Rename from "Don't zap private pages for unsupported cases", and split
   many parts out.
 - Don't support MTRR, apic zapping (Rick)
 - Detangle private/shared alias logic in kvm_tdp_mmu_unmap_gfn_range()
   (Rick)
 - Fix TLB flushing bug debugged by (Chao Gao)
   https://lore.kernel.org/kvm/Zh8yHEiOKyvZO+QR@chao-email/
 - Split out MTRR part
 - Use enum based root iterators (Sean)
 - Reorder logic in kvm_mmu_zap_memslot_leafs().
 - Replace skip_private with enum kvm_tdp_mmu_root_type.
---
 arch/x86/kvm/mmu/tdp_mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index da6024b8295f..0caa1029b6bd 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1135,6 +1135,7 @@ void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm)
 void kvm_tdp_mmu_invalidate_roots(struct kvm *kvm,
 				  enum kvm_process process_types)
 {
+	enum kvm_tdp_mmu_root_types root_types = kvm_process_to_root_types(kvm, process_types);
 	struct kvm_mmu_page *root;
 
 	/*
@@ -1158,6 +1159,9 @@ void kvm_tdp_mmu_invalidate_roots(struct kvm *kvm,
 	 * or get/put references to roots.
 	 */
 	list_for_each_entry(root, &kvm->arch.tdp_mmu_roots, link) {
+		if (!tdp_mmu_root_match(root, root_types))
+			continue;
+
 		/*
 		 * Note, invalid roots can outlive a memslot update!  Invalid
 		 * roots must be *zapped* before the memslot update completes,
-- 
2.34.1