linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] KVM: debugfs: expose pid of vcpu threads
@ 2022-05-23 19:03 Vineeth Pillai (Google)
  2022-06-24 16:01 ` Paolo Bonzini
  0 siblings, 1 reply; 2+ messages in thread
From: Vineeth Pillai (Google) @ 2022-05-23 19:03 UTC (permalink / raw)
  To: Paolo Bonzini, kvm
  Cc: Vineeth Pillai, linux-kernel, Steven Rostedt, Joel Fernandes

From: Vineeth Pillai <vineeth@bitbyteword.org>

Add a new debugfs file to expose the pid of each vcpu threads. This
is very helpful for userland tools to get the vcpu pids without
worrying about thread naming conventions of the VMM.

Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org>
---
 include/linux/kvm_host.h |  2 ++
 virt/kvm/kvm_main.c      | 15 +++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 34eed5f85ed6..c2c86fce761c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1434,6 +1434,8 @@ int kvm_arch_pm_notifier(struct kvm *kvm, unsigned long state);
 
 #ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
 void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry);
+#else
+static inline void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu) {}
 #endif
 
 int kvm_arch_hardware_enable(void);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5ab12214e18d..9bb1dbf51c90 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3723,9 +3723,18 @@ static int create_vcpu_fd(struct kvm_vcpu *vcpu)
 	return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);
 }
 
+#ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
+static int vcpu_get_pid(void *data, u64 *val)
+{
+	struct kvm_vcpu *vcpu = (struct kvm_vcpu *) data;
+	*val = pid_nr(rcu_access_pointer(vcpu->pid));
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(vcpu_get_pid_fops, vcpu_get_pid, NULL, "%llu\n");
+
 static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 {
-#ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
 	struct dentry *debugfs_dentry;
 	char dir_name[ITOA_MAX_LEN * 2];
 
@@ -3735,10 +3744,12 @@ static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
 	debugfs_dentry = debugfs_create_dir(dir_name,
 					    vcpu->kvm->debugfs_dentry);
+	debugfs_create_file("pid", 0444, debugfs_dentry, vcpu,
+			    &vcpu_get_pid_fops);
 
 	kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry);
-#endif
 }
+#endif
 
 /*
  * Creates some virtual cpus.  Good luck creating more than one.
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] KVM: debugfs: expose pid of vcpu threads
  2022-05-23 19:03 [PATCH] KVM: debugfs: expose pid of vcpu threads Vineeth Pillai (Google)
@ 2022-06-24 16:01 ` Paolo Bonzini
  0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2022-06-24 16:01 UTC (permalink / raw)
  To: Vineeth Pillai; +Cc: kvm, linux-kernel, Steven Rostedt, Joel Fernandes

Queued, thanks.

Paolo



^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2022-06-24 16:01 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-23 19:03 [PATCH] KVM: debugfs: expose pid of vcpu threads Vineeth Pillai (Google)
2022-06-24 16:01 ` Paolo Bonzini

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).