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kvm: create per-vcpu dirs in debugfs

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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: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Luiz Capitulino 2016-09-16 10:27:35 -04:00 committed by Paolo Bonzini
parent 235539b48a
commit 45b5939e50
2 changed files with 33 additions and 0 deletions
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1
include/linux/kvm_host.h
View File

@ -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)

32
virt/kvm/kvm_main.c
View File

@ -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: