From: Ashish Kalra <ashish.kalra@amd.com>

Introduce kvm_arch_gmem_cleanup() to perform architecture-specific
cleanups when the last file descriptor for the guest_memfd inode is
closed. This typically occurs during guest shutdown and termination
and allows for final resource release.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 arch/x86/include/asm/kvm-x86-ops.h | 1 +
 arch/x86/include/asm/kvm_host.h    | 1 +
 arch/x86/kvm/x86.c                 | 7 +++++++
 include/linux/kvm_host.h           | 4 ++++
 virt/kvm/Kconfig                   | 4 ++++
 virt/kvm/guest_memfd.c             | 8 ++++++++
 6 files changed, 25 insertions(+)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index de709fb5bd76..ebbecd0c9e4f 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -148,6 +148,7 @@ KVM_X86_OP_OPTIONAL(alloc_apic_backing_page)
 KVM_X86_OP_OPTIONAL_RET0(gmem_prepare)
 KVM_X86_OP_OPTIONAL_RET0(gmem_max_mapping_level)
 KVM_X86_OP_OPTIONAL(gmem_invalidate)
+KVM_X86_OP_OPTIONAL(gmem_cleanup)
 
 #undef KVM_X86_OP
 #undef KVM_X86_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ff07c45e3c73..7894cf791fef 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1962,6 +1962,7 @@ struct kvm_x86_ops {
 	int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order);
 	void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end);
 	int (*gmem_max_mapping_level)(struct kvm *kvm, kvm_pfn_t pfn, bool is_private);
+	void (*gmem_cleanup)(void);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3fb64905d190..d992848942c3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -14080,6 +14080,13 @@ void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end)
 	kvm_x86_call(gmem_invalidate)(start, end);
 }
 #endif
+
+#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CLEANUP
+void kvm_arch_gmem_cleanup(void)
+{
+	kvm_x86_call(gmem_cleanup)();
+}
+#endif
 #endif
 
 int kvm_spec_ctrl_test_value(u64 value)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index dde605cb894e..b14143c427eb 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2607,6 +2607,10 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void __user *src, long npages
 void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
 #endif
 
+#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CLEANUP
+void kvm_arch_gmem_cleanup(void);
+#endif
+
 #ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
 long kvm_arch_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu,
 				    struct kvm_pre_fault_memory *range);
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 267c7369c765..9072ec12d5e7 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -125,3 +125,7 @@ config HAVE_KVM_ARCH_GMEM_INVALIDATE
 config HAVE_KVM_ARCH_GMEM_POPULATE
        bool
        depends on KVM_GUEST_MEMFD
+
+config HAVE_KVM_ARCH_GMEM_CLEANUP
+       bool
+       depends on KVM_GUEST_MEMFD
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 017d84a7adf3..2724dd1099f2 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -955,6 +955,14 @@ static void kvm_gmem_destroy_inode(struct inode *inode)
 
 static void kvm_gmem_free_inode(struct inode *inode)
 {
+#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_CLEANUP
+	/*
+	 * Finalize cleanup for the inode once the last guest_memfd
+	 * reference is released. This usually occurs after guest
+	 * termination.
+	 */
+	kvm_arch_gmem_cleanup();
+#endif
 	kmem_cache_free(kvm_gmem_inode_cachep, GMEM_I(inode));
 }
 
-- 
2.43.0