linux-kernel - [RFC PATCH v1 12/37] KVM: Move KVM_VM_MEMORY

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Message-ID: <36defde6a09d2a7b4ff5507b752546a906b262f9.1760731772.git.ackerleytng@google.com>
Date: Fri, 17 Oct 2025 13:11:53 -0700
From: Ackerley Tng <ackerleytng@...gle.com>
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Subject: [RFC PATCH v1 12/37] KVM: Move KVM_VM_MEMORY_ATTRIBUTES config
 definition to x86

From: Sean Christopherson <seanjc@...gle.com>

Bury KVM_VM_MEMORY_ATTRIBUTES in x86 to discourage other architectures
from adding support for per-VM memory attributes, because tracking private
vs. shared memory on a per-VM basis is now deprecated in favor of tracking
on a per-guest_memfd basis, and no other memory attributes are on the
horizon.

This will also allow modifying KVM_VM_MEMORY_ATTRIBUTES to be
user-selectable (in x86) without creating weirdness in KVM's Kconfigs.
Now that guest_memfd support memory attributes, it's entirely possible to
run x86 CoCo VMs without support for KVM_VM_MEMORY_ATTRIBUTES.

Leave the code itself in common KVM so that it's trivial to undo this
change if new per-VM attributes do come along.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/Kconfig | 4 ++++
 virt/kvm/Kconfig     | 4 ----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index acb03b45ba050..49c7709e3d895 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -80,6 +80,10 @@ config KVM_WERROR
 
 	  If in doubt, say "N".
 
+config KVM_VM_MEMORY_ATTRIBUTES
+	select KVM_MEMORY_ATTRIBUTES
+	bool
+
 config KVM_SW_PROTECTED_VM
 	bool "Enable support for KVM software-protected VMs"
 	depends on EXPERT
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index b3473aec4d24d..72b19813e5412 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -112,10 +112,6 @@ config KVM_MEMORY_ATTRIBUTES
        depends on KVM_GENERIC_MMU_NOTIFIER
        bool
 
-config KVM_VM_MEMORY_ATTRIBUTES
-       select KVM_MEMORY_ATTRIBUTES
-       bool
-
 config KVM_GUEST_MEMFD
        select KVM_MEMORY_ATTRIBUTES
        select XARRAY_MULTI
-- 
2.51.0.858.gf9c4a03a3a-goog