KVM: Add VMSAVE/VMLOAD functions to x86 SVM library

Link: https://lore.kernel.org/ltp/20240430122208.13043-8-mdoucha@suse.cz/
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Martin Doucha <mdoucha@suse.cz>

Author: mdoucha

testcases/kernel/kvm/include/kvm_x86_svm.h

@@ -163,4 +163,10 @@ struct kvm_svm_vcpu *kvm_create_svm_vcpu(int (*guest_main)(void),
 
 void kvm_svm_vmrun(struct kvm_svm_vcpu *cpu);
 
+/* Load FS, GS, TR and LDTR state from vmsave_buf */
+void kvm_svm_vmload(struct kvm_vmcb *buf);
+
+/* Save current FS, GS, TR and LDTR state to vmsave_buf */
+void kvm_svm_vmsave(struct kvm_vmcb *buf);
+
 #endif /* KVM_X86_SVM_H_ */

testcases/kernel/kvm/kvm_svm02.c

@@ -33,22 +33,14 @@ static void *vmsave_buf;
 /* Load FS, GS, TR and LDTR state from vmsave_buf */
 static int guest_vmload(void)
 {
-	asm (
-		"vmload %0\n"
-		:
-		: "a" (vmsave_buf)
-	);
+	kvm_svm_vmload(vmsave_buf);
 	return 0;
 }
 
 /* Save current FS, GS, TR and LDTR state to vmsave_buf */
 static int guest_vmsave(void)
 {
-	asm (
-		"vmsave %0\n"
-		:
-		: "a" (vmsave_buf)
-	);
+	kvm_svm_vmsave(vmsave_buf);
 	return 0;
 }
 

testcases/kernel/kvm/lib_x86.c

@@ -393,3 +393,21 @@ struct kvm_svm_vcpu *kvm_create_svm_vcpu(int (*guest_main)(void),
 	ret->vmcb = vmcb;
 	return ret;
 }
+
+void kvm_svm_vmload(struct kvm_vmcb *buf)
+{
+	asm (
+		"vmload %0\n"
+		:
+		: "a" (buf)
+	);
+}
+
+void kvm_svm_vmsave(struct kvm_vmcb *buf)
+{
+	asm (
+		"vmsave %0\n"
+		:
+		: "a" (buf)
+	);
+}