KVM: x86: Open code shared_msr_update() in its only caller

This change “KVM: x86: Open code shared_msr_update() in its only caller” (commit 05c19c2) in Linux kernel is authored by Sean Christopherson <sean.j.christopherson [at] intel.com> on Fri Nov 22 12:04:50 2019 -0800.

Description of "KVM: x86: Open code shared_msr_update() in its only caller"

The change “KVM: x86: Open code shared_msr_update() in its only caller” introduces changes as follows.

KVM: x86: Open code shared_msr_update() in its only caller

Fold shared_msr_update() into its sole user to eliminate its pointless
bounds check, its godawful printk, its misleading comment (it's called
under a global lock), and its woefully inaccurate name.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Linux kernel releases containing commit 05c19c2

The Linux kernel releases containing this commit are as follows.

Linux kernel code changes from "KVM: x86: Open code shared_msr_update() in its only caller"

There are 29 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 arch/x86/kvm/x86.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3e9ab2d1ea77..f5db520f2ac3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -262,23 +262,6 @@ static void kvm_on_user_return(struct user_return_notifier *urn)
 	}
 }
 
-static void shared_msr_update(unsigned slot, u32 msr)
-{
-	u64 value;
-	unsigned int cpu = smp_processor_id();
-	struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);
-
-	/* only read, and nobody should modify it at this time,
-	 * so don't need lock */
-	if (slot >= shared_msrs_global.nr) {
-		printk(KERN_ERR "kvm: invalid MSR slot!");
-		return;
-	}
-	rdmsrl_safe(msr, &value);
-	smsr->values[slot].host = value;
-	smsr->values[slot].curr = value;
-}
-
 void kvm_define_shared_msr(unsigned slot, u32 msr)
 {
 	BUG_ON(slot >= KVM_NR_SHARED_MSRS);
@@ -290,10 +273,16 @@ EXPORT_SYMBOL_GPL(kvm_define_shared_msr);
 
 static void kvm_shared_msr_cpu_online(void)
 {
-	unsigned i;
+	unsigned int cpu = smp_processor_id();
+	struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);
+	u64 value;
+	int i;
 
-	for (i = 0; i < shared_msrs_global.nr; ++i)
-		shared_msr_update(i, shared_msrs_global.msrs[i]);
+	for (i = 0; i < shared_msrs_global.nr; ++i) {
+		rdmsrl_safe(shared_msrs_global.msrs[i], &value);
+		smsr->values[i].host = value;
+		smsr->values[i].curr = value;
+	}
 }
 
 int kvm_set_shared_msr(unsigned slot, u64 value, u64 mask)

The commit for this change in Linux stable tree is 05c19c2 (patch).

Last modified: 2020/02/08