On Wed, Sep 11, 2024 at 03:58:23PM +0100, Alejandro Vallejo wrote: > Moves sti directly after the cr2 read and immediately after the #PF > handler. > > While in the area, remove redundant q suffix to a movq in entry.S > > Signed-off-by: Alejandro Vallejo <alejandro.vall...@cloud.com> > --- > I don't think this is a bug as much as an accident about to happen. Even if > there's no cases at the moment in which the IRQ handler may page fault, that > might change in the future. > > Note: I haven't tested it extensively beyond running it on GitLab. > > pipeline: > https://gitlab.com/xen-project/people/agvallejo/xen/-/pipelines/1449182525 > > --- > xen/arch/x86/traps.c | 2 ++ > xen/arch/x86/x86_64/entry.S | 11 +++++++++-- > 2 files changed, 11 insertions(+), 2 deletions(-) > > diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c > index 708136f625..1c04c03d9f 100644 > --- a/xen/arch/x86/traps.c > +++ b/xen/arch/x86/traps.c > @@ -1600,6 +1600,8 @@ void asmlinkage do_page_fault(struct cpu_user_regs > *regs) > > addr = read_cr2(); > > + local_irq_enable();
I would maybe add an ASSERT(!local_irq_is_enabled()); at the top of the function, just to make sure the context is as expected. > + > /* fixup_page_fault() might change regs->error_code, so cache it here. */ > error_code = regs->error_code; > > diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S > index b8482de8ee..ef803f6288 100644 > --- a/xen/arch/x86/x86_64/entry.S > +++ b/xen/arch/x86/x86_64/entry.S > @@ -844,8 +844,7 @@ handle_exception_saved: > #elif !defined(CONFIG_PV) > ASSERT_CONTEXT_IS_XEN > #endif /* CONFIG_PV */ > - sti > -1: movq %rsp,%rdi > +1: mov %rsp,%rdi Since you are modifying this already - we usually add a space between the comma and the next operand. Thanks, Roger.
