linux-kernel - [PATCH] KVM: x86: User mutex guards to eliminate __kvm_x86_vendor

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Date:   Mon, 30 Oct 2023 16:17:28 +0200
From:   Nikolay Borisov <nik.borisov@...e.com>
To:     seanjc@...gle.com
Cc:     pbonzini@...hat.com, x86@...nel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Nikolay Borisov <nik.borisov@...e.com>
Subject: [PATCH] KVM: x86: User mutex guards to eliminate __kvm_x86_vendor_init()

Current separation between (__){0,1}kvm_x86_vendor_init() is superfluos as
the the underscore version doesn't have any other callers.

Instead, use the newly added cleanup infrastructure to ensure that
kvm_x86_vendor_init() holds the vendor_module_lock throughout its
exectuion and that in case of error in the middle it's released. No
functional changes.

Signed-off-by: Nikolay Borisov <nik.borisov@...e.com>
---
 arch/x86/kvm/x86.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 41cce5031126..cd7c2d0f88cb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9446,11 +9446,13 @@ static void kvm_x86_check_cpu_compat(void *ret)
 	*(int *)ret = kvm_x86_check_processor_compatibility();
 }
 
-static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
+int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 {
 	u64 host_pat;
 	int r, cpu;
 
+	guard(mutex)(&vendor_module_lock);
+
 	if (kvm_x86_ops.hardware_enable) {
 		pr_err("already loaded vendor module '%s'\n", kvm_x86_ops.name);
 		return -EEXIST;
@@ -9580,17 +9582,6 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 	kmem_cache_destroy(x86_emulator_cache);
 	return r;
 }
-
-int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
-{
-	int r;
-
-	mutex_lock(&vendor_module_lock);
-	r = __kvm_x86_vendor_init(ops);
-	mutex_unlock(&vendor_module_lock);
-
-	return r;
-}
 EXPORT_SYMBOL_GPL(kvm_x86_vendor_init);
 
 void kvm_x86_vendor_exit(void)
-- 
2.34.1