On Wed, 23 Sep 2026 07:33:15 -0700 Sean Christopherson <[email protected]> wrote:
> On Wed, Sep 23, 2026, Peter Zijlstra wrote: > > On Tue, Sep 22, 2026 at 01:25:07PM +0900, Masami Hiramatsu (Google) wrote: > > > From: Masami Hiramatsu (Google) <[email protected]> > > > > > > When KVM enters a guest OS, host hardware breakpoints are disabled > > > before running the guest. However, an NMI can occur while executing > > > in guest mode or during guest transition, where > > > arch_install_hw_breakpoint() can be invoked from NMI context. > > > > How? AFAICT perf doesn't do that. arch_install_hw_breakpoint() is called > > through pmu::add() which is strictly IPI context. > > I assume it's: > > kgdb_nmi_handler() > | > -> kgdb_nmicallin() > | > -> kgdb_cpu_enter() > | > -> arch_kgdb_ops.correct_hw_break() > | > -> kgdb_correct_hw_break() > | > -> arch_install_hw_breakpoint() Yes, it is done by KGDB. perf has no problem with it. Thank you, -- Masami Hiramatsu (Google) <[email protected]>
