Message-ID: <20250729225455.670324-6-seanjc@google.com>
Date: Tue, 29 Jul 2025 15:54:36 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>, 
	Oliver Upton <oliver.upton@...ux.dev>, Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	Ira Weiny <ira.weiny@...el.com>, Gavin Shan <gshan@...hat.com>, Shivank Garg <shivankg@....com>, 
	Vlastimil Babka <vbabka@...e.cz>, Xiaoyao Li <xiaoyao.li@...el.com>, 
	David Hildenbrand <david@...hat.com>, Fuad Tabba <tabba@...gle.com>, 
	Ackerley Tng <ackerleytng@...gle.com>, Tao Chan <chentao@...inos.cn>, 
	James Houghton <jthoughton@...gle.com>
Subject: [PATCH v17 05/24] KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE

From: Fuad Tabba <tabba@...gle.com>

The original name was vague regarding its functionality. This Kconfig
option specifically enables and gates the kvm_gmem_populate() function,
which is responsible for populating a GPA range with guest data.

The new name, HAVE_KVM_ARCH_GMEM_POPULATE, describes the purpose of the
option: to enable arch-specific guest_memfd population mechanisms. It
also follows the same pattern as the other HAVE_KVM_ARCH_* configuration
options.

This improves clarity for developers and ensures the name accurately
reflects the functionality it controls, especially as guest_memfd
support expands beyond purely "private" memory scenarios.

Temporarily keep KVM_GENERIC_PRIVATE_MEM as an x86-only config so as to
minimize churn, and to hopefully make it easier to see what features
require HAVE_KVM_ARCH_GMEM_POPULATE.  On that note, omit GMEM_POPULATE
for KVM_X86_SW_PROTECTED_VM, as regular ol' memset() suffices for
software-protected VMs.

As for KVM_GENERIC_PRIVATE_MEM, a future change will select KVM_GUEST_MEMFD
for all 64-bit KVM builds, at which point the intermediate config will
become obsolete and can/will be dropped.

Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Reviewed-by: Gavin Shan <gshan@...hat.com>
Reviewed-by: Shivank Garg <shivankg@....com>
Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
Co-developed-by: David Hildenbrand <david@...hat.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
Signed-off-by: Fuad Tabba <tabba@...gle.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@...el.com>
Co-developed-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/Kconfig     | 14 ++++++++++----
 include/linux/kvm_host.h |  2 +-
 virt/kvm/Kconfig         |  9 ++++-----
 virt/kvm/guest_memfd.c   |  2 +-
 4 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 13ab7265b505..c763446d9b9f 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -79,11 +79,16 @@ config KVM_WERROR
 
 	  If in doubt, say "N".
 
+config KVM_X86_PRIVATE_MEM
+	select KVM_GENERIC_MEMORY_ATTRIBUTES
+	select KVM_GUEST_MEMFD
+	bool
+
 config KVM_SW_PROTECTED_VM
 	bool "Enable support for KVM software-protected VMs"
 	depends on EXPERT
 	depends on KVM_X86 && X86_64
-	select KVM_GENERIC_PRIVATE_MEM
+	select KVM_X86_PRIVATE_MEM
 	help
 	  Enable support for KVM software-protected VMs.  Currently, software-
 	  protected VMs are purely a development and testing vehicle for
@@ -133,8 +138,8 @@ config KVM_INTEL_TDX
 	bool "Intel Trust Domain Extensions (TDX) support"
 	default y
 	depends on INTEL_TDX_HOST
-	select KVM_GENERIC_PRIVATE_MEM
-	select KVM_GENERIC_MEMORY_ATTRIBUTES
+	select KVM_X86_PRIVATE_MEM
+	select HAVE_KVM_ARCH_GMEM_POPULATE
 	help
 	  Provides support for launching Intel Trust Domain Extensions (TDX)
 	  confidential VMs on Intel processors.
@@ -157,9 +162,10 @@ config KVM_AMD_SEV
 	depends on KVM_AMD && X86_64
 	depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
 	select ARCH_HAS_CC_PLATFORM
-	select KVM_GENERIC_PRIVATE_MEM
+	select KVM_X86_PRIVATE_MEM
 	select HAVE_KVM_ARCH_GMEM_PREPARE
 	select HAVE_KVM_ARCH_GMEM_INVALIDATE
+	select HAVE_KVM_ARCH_GMEM_POPULATE
 	help
 	  Provides support for launching encrypted VMs which use Secure
 	  Encrypted Virtualization (SEV), Secure Encrypted Virtualization with
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 8cdc0b3cc1b1..ddfb6cfe20a6 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2534,7 +2534,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,
 int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order);
 #endif
 
-#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
+#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
 /**
  * kvm_gmem_populate() - Populate/prepare a GPA range with guest data
  *
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index e4b400feff94..1b7d5be0b6c4 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -116,11 +116,6 @@ config KVM_GUEST_MEMFD
        select XARRAY_MULTI
        bool
 
-config KVM_GENERIC_PRIVATE_MEM
-       select KVM_GENERIC_MEMORY_ATTRIBUTES
-       select KVM_GUEST_MEMFD
-       bool
-
 config HAVE_KVM_ARCH_GMEM_PREPARE
        bool
        depends on KVM_GUEST_MEMFD
@@ -128,3 +123,7 @@ config HAVE_KVM_ARCH_GMEM_PREPARE
 config HAVE_KVM_ARCH_GMEM_INVALIDATE
        bool
        depends on KVM_GUEST_MEMFD
+
+config HAVE_KVM_ARCH_GMEM_POPULATE
+       bool
+       depends on KVM_GUEST_MEMFD
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 7d85cc33c0bb..b2b50560e80e 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -627,7 +627,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 }
 EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn);
 
-#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
+#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
 long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages,
 		       kvm_gmem_populate_cb post_populate, void *opaque)
 {
-- 
2.50.1.552.g942d659e1b-goog

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