On 7/15/2025 5:33 PM, Fuad Tabba wrote:
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.
Well, I disagree.
The config KVM_GENERIC_PRIVATE_MEM was introduced by commit 89ea60c2c7b5
("KVM: x86: Add support for "protected VMs" that can utilize private
memory"), which is a convenient config for vm types that requires
private memory support, e.g., SNP, TDX, and KVM_X86_SW_PROTECTED_VM.
It was commit e4ee54479273 ("KVM: guest_memfd: let kvm_gmem_populate()
operate only on private gfns") that started to use
CONFIG_KVM_GENERIC_PRIVATE_MEM gates kvm_gmem_populate() function. But
CONFIG_KVM_GENERIC_PRIVATE_MEM is not for kvm_gmem_populate() only.
If using CONFIG_KVM_GENERIC_PRIVATE_MEM to gate kvm_gmem_populate() is
vague and confusing, we can introduce KVM_GENERIC_GMEM_POPULATE to gate
kvm_gmem_populate() and select KVM_GENERIC_GMEM_POPULATE under
CONFIG_KVM_GENERIC_PRIVATE_MEM.
Directly replace CONFIG_KVM_GENERIC_PRIVATE_MEM with
KVM_GENERIC_GMEM_POPULATE doesn't look correct to me.
The new name, KVM_GENERIC_GMEM_POPULATE, describes the purpose of the
option: to enable generic guest_memfd population mechanisms. 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.
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
Reviewed-by: Shivank Garg <shivankg@xxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Co-developed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
arch/x86/kvm/Kconfig | 6 +++---
include/linux/kvm_host.h | 2 +-
virt/kvm/Kconfig | 2 +-
virt/kvm/guest_memfd.c | 2 +-
4 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 2eeffcec5382..df1fdbb4024b 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -46,7 +46,7 @@ config KVM_X86
select HAVE_KVM_PM_NOTIFIER if PM
select KVM_GENERIC_HARDWARE_ENABLING
select KVM_GENERIC_PRE_FAULT_MEMORY
- select KVM_GENERIC_PRIVATE_MEM if KVM_SW_PROTECTED_VM
+ select KVM_GENERIC_GMEM_POPULATE if KVM_SW_PROTECTED_VM
select KVM_WERROR if WERROR
config KVM
@@ -95,7 +95,7 @@ config KVM_SW_PROTECTED_VM
config KVM_INTEL
tristate "KVM for Intel (and compatible) processors support"
depends on KVM && IA32_FEAT_CTL
- select KVM_GENERIC_PRIVATE_MEM if INTEL_TDX_HOST
+ select KVM_GENERIC_GMEM_POPULATE if INTEL_TDX_HOST
select KVM_GENERIC_MEMORY_ATTRIBUTES if INTEL_TDX_HOST
help
Provides support for KVM on processors equipped with Intel's VT
@@ -157,7 +157,7 @@ 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_GENERIC_GMEM_POPULATE
select HAVE_KVM_ARCH_GMEM_PREPARE
select HAVE_KVM_ARCH_GMEM_INVALIDATE
help
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 755b09dcafce..359baaae5e9f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2556,7 +2556,7 @@ 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_KVM_GENERIC_GMEM_POPULATE
/**
* kvm_gmem_populate() - Populate/prepare a GPA range with guest data
*
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 49df4e32bff7..559c93ad90be 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -116,7 +116,7 @@ config KVM_GMEM
select XARRAY_MULTI
bool
-config KVM_GENERIC_PRIVATE_MEM
+config KVM_GENERIC_GMEM_POPULATE
select KVM_GENERIC_MEMORY_ATTRIBUTES
select KVM_GMEM
bool
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index b2aa6bf24d3a..befea51bbc75 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -638,7 +638,7 @@ 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_KVM_GENERIC_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)
{
