KVM: VAC: Move user_return_msrs allocation into the vac

Allocating in KVM meant module load would overwrite the table; and unloading one kvm would free the table from other running ones (oops). Move alloc/dealloc to vac and make the table private. Signed-off-by: Venkatesh Srinivas <[email protected]>
vsrinivas · Jun 28, 2023 · 09087b2 · 09087b2
1 parent 333fbf0
commit 09087b2
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Showing 2 changed files with 13 additions and 12 deletions.
diff --git a/arch/x86/kvm/vac.c b/arch/x86/kvm/vac.c
@@ -9,7 +9,6 @@
 u32 __read_mostly kvm_uret_msrs_list[KVM_MAX_NR_USER_RETURN_MSRS];
 EXPORT_SYMBOL(kvm_uret_msrs_list);
 struct kvm_user_return_msrs __percpu *user_return_msrs;
-EXPORT_SYMBOL(user_return_msrs);
 
 u32 __read_mostly kvm_nr_uret_msrs;
 EXPORT_SYMBOL(kvm_nr_uret_msrs);
@@ -160,6 +159,13 @@ void kvm_arch_hardware_disable(void)
 
 int __init vac_init(void)
 {
+        user_return_msrs = alloc_percpu(struct kvm_user_return_msrs);
+        if (!user_return_msrs) {
+                pr_err("failed to allocate percpu kvm_user_return_msrs\n");
+                return -ENOMEM;
+        }
+	kvm_nr_uret_msrs = 0;
+
 #ifdef CONFIG_KVM_INTEL
 	if (cpu_has_vmx())
 		return vac_vmx_init();
@@ -172,6 +178,12 @@ int __init vac_init(void)
 }
 module_init(vac_init);
 
+void __exit vac_exit(void)
+{
+	free_percpu(user_return_msrs);
+}
+module_exit(vac_exit);
+
 /*
  * Handle a fault on a hardware virtualization (VMX or SVM) instruction.
  *

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
@@ -9244,14 +9244,6 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 		return -ENOMEM;
 	}
 
-	user_return_msrs = alloc_percpu(struct kvm_user_return_msrs);
-	if (!user_return_msrs) {
-		pr_err("failed to allocate percpu kvm_user_return_msrs\n");
-		r = -ENOMEM;
-		goto out_free_x86_emulator_cache;
-	}
-	kvm_nr_uret_msrs = 0;
-
 	r = kvm_mmu_vendor_module_init();
 	if (r)
 		goto out_free_percpu;
@@ -9325,8 +9317,6 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 out_mmu_exit:
 	kvm_mmu_vendor_module_exit();
 out_free_percpu:
-	free_percpu(user_return_msrs);
-out_free_x86_emulator_cache:
 	kmem_cache_destroy(x86_emulator_cache);
 	return r;
 }
@@ -9364,7 +9354,6 @@ void kvm_x86_vendor_exit(void)
 #endif
 	static_call(kvm_x86_hardware_unsetup)();
 	kvm_mmu_vendor_module_exit();
-	free_percpu(user_return_msrs);
 	kmem_cache_destroy(x86_emulator_cache);
 #ifdef CONFIG_KVM_XEN
 	static_key_deferred_flush(&kvm_xen_enabled);