From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Sebastian Siewior <bigeasy@linutronix.de>,
Anna-Maria Gleixner <anna-maria@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Julia Cartwright <julia@ni.com>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
kvm@vger.kernel.org, Radim Krcmar <rkrcmar@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
John Stultz <john.stultz@linaro.org>,
Andy Lutomirski <luto@kernel.org>,
"Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: [patch 1/5] tracehook: Provide TIF_NOTIFY_RESUME handling for KVM
Date: Thu, 01 Aug 2019 16:32:51 +0200 [thread overview]
Message-ID: <20190801143657.785902257@linutronix.de> (raw)
In-Reply-To: 20190801143250.370326052@linutronix.de
TIF_NOTITY_RESUME is evaluated on return to user space along with other TIF
flags.
>From the kernels point of view a VMENTER is more or less equivalent to
return to user space which means that at least a subset of TIF flags needs
to be evaluated and handled.
Currently KVM handles only TIF_SIGPENDING and TIF_NEED_RESCHED, but
TIF_NOTIFY_RESUME is ignored. So pending task_work etc, is completely
ignored until the vCPU thread actually goes all the way back into
userspace/qemu.
Provide notify_resume_pending() and tracehook_handle_notify_resume() so
this can be handled similar to SIGPENDING.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
---
include/linux/tracehook.h | 15 +++++++++++++++
kernel/task_work.c | 19 +++++++++++++++++++
2 files changed, 34 insertions(+)
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -163,6 +163,21 @@ static inline void set_notify_resume(str
#endif
}
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+/**
+ * notify_resume_pending - Check whether current has TIF_NOTIFY_RESUME set
+ */
+static inline bool notify_resume_pending(void)
+{
+ return test_thread_flag(TIF_NOTIFY_RESUME);
+}
+
+void tracehook_handle_notify_resume(void);
+#else
+static inline bool notify_resume_pending(void) { return false; }
+static inline void tracehook_handle_notify_resume(void) { }
+#endif
+
/**
* tracehook_notify_resume - report when about to return to user mode
* @regs: user-mode registers of @current task
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -116,3 +116,22 @@ void task_work_run(void)
} while (work);
}
}
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+/**
+ * tracehook_handle_notify_resume - Notify resume handling for virt
+ *
+ * Called with interrupts and preemption enabled from VMENTER/EXIT.
+ */
+void tracehook_handle_notify_resume(void)
+{
+ local_irq_disable();
+ while (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+ local_irq_enable();
+ tracehook_notify_resume(NULL);
+ local_irq_disable();
+ }
+ local_irq_enable();
+}
+EXPORT_SYMBOL_GPL(tracehook_handle_notify_resume);
+#endif
next prev parent reply other threads:[~2019-08-01 14:38 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 14:32 [patch 0/5] posix-cpu-timers: Move expiry into task work context Thomas Gleixner
2019-08-01 14:32 ` Thomas Gleixner [this message]
2019-08-01 14:48 ` [patch 1/5] tracehook: Provide TIF_NOTIFY_RESUME handling for KVM Peter Zijlstra
2019-08-01 15:10 ` Thomas Gleixner
2019-08-01 17:02 ` Andy Lutomirski
2019-08-01 14:32 ` [patch 2/5] x86/kvm: Handle task_work on VMENTER/EXIT Thomas Gleixner
2019-08-01 16:24 ` Oleg Nesterov
2019-08-01 18:34 ` Thomas Gleixner
2019-08-01 21:35 ` Sean Christopherson
2019-08-01 21:44 ` Peter Zijlstra
2019-08-01 21:44 ` Thomas Gleixner
2019-08-01 21:47 ` Thomas Gleixner
2019-08-02 21:35 ` Paolo Bonzini
2019-08-02 22:22 ` Thomas Gleixner
2019-08-02 22:39 ` Andy Lutomirski
2019-08-02 12:04 ` Oleg Nesterov
2019-08-01 14:32 ` [patch 3/5] posix-cpu-timers: Split run_posix_cpu_timers() Thomas Gleixner
2019-08-01 14:32 ` [patch 4/5] posix-cpu-timers: Defer timer handling to task_work Thomas Gleixner
2019-08-01 14:51 ` Peter Zijlstra
2019-08-01 15:10 ` Thomas Gleixner
2019-08-01 15:39 ` Oleg Nesterov
2019-08-01 18:41 ` Thomas Gleixner
2019-08-01 14:32 ` [patch 5/5] x86: Select POSIX_CPU_TIMERS_TASK_WORK Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190801143657.785902257@linutronix.de \
--to=tglx@linutronix.de \
--cc=anna-maria@linutronix.de \
--cc=bigeasy@linutronix.de \
--cc=fweisbec@gmail.com \
--cc=john.stultz@linaro.org \
--cc=julia@ni.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=oleg@redhat.com \
--cc=paulmck@linux.ibm.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=rkrcmar@redhat.com \
--cc=rostedt@goodmis.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).