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Commit 45b5939e authored by Luiz Capitulino's avatar Luiz Capitulino Committed by Paolo Bonzini
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kvm: create per-vcpu dirs in debugfs 



This commit adds the ability for archs to export
per-vcpu information via a new per-vcpu dir in
the VM's debugfs directory.

If kvm_arch_has_vcpu_debugfs() returns true, then KVM
will create a vcpu dir for each vCPU in the VM's
debugfs directory. Then kvm_arch_create_vcpu_debugfs()
is responsible for populating each vcpu directory
with arch specific entries.

The per-vcpu path in debugfs will look like:

/sys/kernel/debug/kvm/29162-10/vcpu0
/sys/kernel/debug/kvm/29162-10/vcpu1

This is all arch specific for now because the only
user of this interface (x86) wants to export x86-specific
per-vcpu information to user-space.

Signed-off-by: default avatarLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 235539b4

include/linux/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ struct kvm_vcpu { 
#endif

	bool preempted;

	struct kvm_vcpu_arch arch;

	struct dentry *debugfs_dentry;

};



static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu)

virt/kvm/kvm_main.c

+32 −0
Original line number Diff line number Diff line
@@ -2371,6 +2371,7 @@ static int kvm_vcpu_release(struct inode *inode, struct file *filp) 
{

	struct kvm_vcpu *vcpu = filp->private_data;



	debugfs_remove_recursive(vcpu->debugfs_dentry);

	kvm_put_kvm(vcpu->kvm);

	return 0;

}
@@ -2393,6 +2394,32 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu) 
	return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);

}



static int kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)

{

	char dir_name[ITOA_MAX_LEN * 2];

	int ret;



	if (!kvm_arch_has_vcpu_debugfs())

		return 0;



	if (!debugfs_initialized())

		return 0;



	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);

	vcpu->debugfs_dentry = debugfs_create_dir(dir_name,

								vcpu->kvm->debugfs_dentry);

	if (!vcpu->debugfs_dentry)

		return -ENOMEM;



	ret = kvm_arch_create_vcpu_debugfs(vcpu);

	if (ret < 0) {

		debugfs_remove_recursive(vcpu->debugfs_dentry);

		return ret;

	}



	return 0;

}



/*

 * Creates some virtual cpus.  Good luck creating more than one.

 */
@@ -2425,6 +2452,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) 
	if (r)

		goto vcpu_destroy;



	r = kvm_create_vcpu_debugfs(vcpu);

	if (r)

		goto vcpu_destroy;



	mutex_lock(&kvm->lock);

	if (kvm_get_vcpu_by_id(kvm, id)) {

		r = -EEXIST;
@@ -2456,6 +2487,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) 


unlock_vcpu_destroy:

	mutex_unlock(&kvm->lock);

	debugfs_remove_recursive(vcpu->debugfs_dentry);

vcpu_destroy:

	kvm_arch_vcpu_destroy(vcpu);

vcpu_decrement: