Le mar. 1 sept. 2020 00:02, Richard Henderson <richard.hender...@linaro.org> a écrit :
> On 8/31/20 2:18 PM, Richard Henderson wrote: > > On 8/19/20 11:28 AM, Robert Foley wrote: > >> Adding ->do_interrupt_locked to ARMCPUClass is preparation for > >> pushing the BQL down into the per-arch implementation of ->do_interrupt. > >> > >> This is needed since ARM's *_cpu_exec_interrupt calls to *_do_interrupt. > >> With the push down of the BQL into *_cpu_exec_interrupt and > >> *_do_interrupt, *_cpu_exec_interrupt will call to ->do_interrupt > >> with lock held. Since ->do_interrupt also has the lock, we need a way > >> to allow cpu_exec_interrupt to call do_interrupt with lock held. > >> This patch solves this issue of *_cpu_exec_interrupt needing > >> to call do_interrupt with lock held. > >> > >> This patch is part of a series of transitions to move the > >> BQL down into the do_interrupt per arch functions. This set of > >> transitions is needed to maintain bisectability. > >> > >> This approach was suggested by Paolo Bonzini. > >> For reference, here are two key posts in the discussion, explaining > >> the reasoning/benefits of this approach. > >> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg00784.html > >> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg01517.html > >> https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg08731.html > >> https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg00044.html > >> > >> Signed-off-by: Robert Foley <robert.fo...@linaro.org> > >> --- > >> target/arm/cpu-qom.h | 3 +++ > >> target/arm/cpu.c | 5 +++-- > >> target/arm/cpu_tcg.c | 5 +++-- > >> 3 files changed, 9 insertions(+), 4 deletions(-) > > > > Reviewed-by: Richard Henderson <richard.hender...@linaro.org> > > I take it back. These two cc->do_interrupt calls can be replaced with > direct > calls. > > > #ifndef CONFIG_USER_ONLY > > cc->do_interrupt = arm_v7m_cpu_do_interrupt; > > #endif > > > > cc->cpu_exec_interrupt = arm_v7m_cpu_exec_interrupt; > > If we are in arm_v7m_cpu_exec_interrupt we will always call > arm_v7m_cpu_do_interrupt. > > I think the mismatch of #ifdef, which implies a different destination is > possible, is a bug -- cc->do_interrupt is not otherwise assigned and in > fact > would be NULL. > > I suspect that some of these slots themselves should be ifdefed, so that we > cannot assign to them when they are unused. That would help keep the > ifdefs in > the cpu init functions in sync. > I tried to do this once but this breaks sizeof(CPUState) archived in libqemu.a vs linking softmmu / user. IIRC Peter explained why we can't do that. I'll search the post tomorrow. > This same condition is *not* true for cris -- there is no > crisv10_cpu_exec_interrupt -- so you do need the new do_interrupt_locked > field > there. > > > r~ > >
