linux-kernel - [PATCH 3/9] KVM: x86/mmu: Move "dummy root" helpers to spte.h

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Message-ID: <20250919005955.1366256-4-seanjc@google.com>
Date: Thu, 18 Sep 2025 17:59:49 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/9] KVM: x86/mmu: Move "dummy root" helpers to spte.h

Move the helpers to get/query a dummy root from mmu_internal.h to spte.h
so that VMX can detect and handle dummy roots when constructing EPTPs.
This will allow using the root's role to build the EPTP instead of pulling
equivalent information out of the vCPU structure.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu_internal.h | 10 ----------
 arch/x86/kvm/mmu/spte.h         | 10 ++++++++++
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index ed5c01df21ba..73cdcbccc89e 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -39,16 +39,6 @@
 #define INVALID_PAE_ROOT	0
 #define IS_VALID_PAE_ROOT(x)	(!!(x))
 
-static inline hpa_t kvm_mmu_get_dummy_root(void)
-{
-	return my_zero_pfn(0) << PAGE_SHIFT;
-}
-
-static inline bool kvm_mmu_is_dummy_root(hpa_t shadow_page)
-{
-	return is_zero_pfn(shadow_page >> PAGE_SHIFT);
-}
-
 typedef u64 __rcu *tdp_ptep_t;
 
 struct kvm_mmu_page {
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 3133f066927e..91ce29fd6f1b 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -246,6 +246,16 @@ static inline int spte_index(u64 *sptep)
  */
 extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
 
+static inline hpa_t kvm_mmu_get_dummy_root(void)
+{
+	return my_zero_pfn(0) << PAGE_SHIFT;
+}
+
+static inline bool kvm_mmu_is_dummy_root(hpa_t shadow_page)
+{
+	return is_zero_pfn(shadow_page >> PAGE_SHIFT);
+}
+
 static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page)
 {
 	struct page *page = pfn_to_page((shadow_page) >> PAGE_SHIFT);
-- 
2.51.0.470.ga7dc726c21-goog