Re: [PATCH v8 08/46] KVM: Provide generic interface for checking memory private/shared status
From: Xiaoyao Li <hidden>
Date: 2026-07-01 07:22:46
Also in:
kvm, linux-coco, linux-doc, linux-kselftest, linux-mm, lkml
On 6/19/2026 8:31 AM, Ackerley Tng via B4 Relay wrote:
From: Sean Christopherson <seanjc@google.com> Introduce a generic kvm_mem_is_private() interface using a static call to determine if a GFN is private. This allows the implementation for checking a GFN's private/shared status to be set at runtime. In preparation for choosing implementations between a guest_memfd lookup and the existing VM attribute lookup, rename the existing VM-attribute-based check to kvm_vm_mem_is_private to emphasize that it looks up VM attributes. Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <redacted> One nit below.
quoted hunk ↗ jump to hunk
--- include/linux/kvm_host.h | 12 +++++++++++- virt/kvm/kvm_main.c | 15 +++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-)diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index eb26d4ea8945a..3915da2a61778 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h@@ -2546,7 +2546,7 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range); -static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) +static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn) { return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; }@@ -2557,6 +2557,16 @@ static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start, KVM_MEMORY_ATTRIBUTE_PRIVATE, KVM_MEMORY_ATTRIBUTE_PRIVATE); } +#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
Since it stops the original #define scope of CONFIG_KVM_VM_MEMORY_ATTRIBUTES here, ...
+#ifdef kvm_arch_has_private_mem
+typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
+DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
+
+static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
+{
+ return static_call(__kvm_mem_is_private)(kvm, gfn);
+}
#else
static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
{... we need to update the comment of #endif to match with the new scope kvm_arch_has_private_mem as below. Or just delete the comment.
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h@@ -2572,7 +2572,7 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
{
return false;
}
-#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
+#endif /* kvm_arch_has_private_mem */
#ifdef CONFIG_KVM_GUEST_MEMFD
int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,