Song will online next week.
Please correct me if there is something wrong, song.
On 2024/5/24 上午7:50, Jiaxun Yang wrote:
在2024年5月21日五月 下午1:32，Song Gao写道：
On LoongArch, IRQs can be routed to four vcpus with hardware extioi.
This patch adds the extioi virt extension support so that the IRQ can
route to 256 vcpus.
Hi Song,
Sorry for chime in here, I'm a little bit confused by this series, can
you give me a little bit of context behind?
Currently interrupt can be routed to only 4 vcpus with one HW extioi. On
virt machine, there are 256 vcpus even more in future.
Extioi virt extension is introduced here to route irq to more vcpus.
I don't see this functionality on 3A5000/3A6000's user manual, so is this
some sort of undocumented hardware feature?
No, it is not real HW, it is Extioi virt extension, it is virt machine
model only.
I checked openEuler kernel patch you referred, it seems like this applies to
hypervisor mode only. I suppose it should be handled by KVM subsystem in
kernel, why do we need this in user mode device emulation?
Will do when irqchip is emulated in kernel. Now irqchip is emulated in
userspace, so it is implemented in userspace firstly.
However it is necessary to emulate in userspace. User can select to
whether to emulate irqchip in userspace or kernel space, user space
emulation is easy to debug, kernel space has higher performance. Both
need extioi virt extension.
Currently, LoongArch's in-kernel irqchip functionality does not include such
feature, can we see KVM side support for this, or at least a draft
specification?
yeap, maybe more documentation need written for the extioi virt
extension model.
We are preparing to port irqchip to kernel space, this function will be
added in kernel space also.
Regards
Bibo Mao
Thanks
- Jiaxun
v3:
- Split patch2 to two small patch.
- remove unused code.
- loongarch_extioi_reset() clear status without checking virt extioi
features.
- Link to v2:
https://patchew.org/QEMU/20240514090756.988096-1-gaos...@loongson.cn/
v2:
- Split the patch to two small patch.
- Drop 'RFC' title. extioi virt extension suport only enable on kvm
mode and the extioi driver need patch[1].
but this series do not affect the old codes in any way.
- Link to v1:
https://lore.kernel.org/all/20240116022526.498613-1-gaos...@loongson.cn/#r
[1]:
https://gitee.com/openeuler/kernel/commit/5d97cff72f91f4f20a536efd60eca75bfcb78a64
Thanks.
Song Gao
Song Gao (3):
hw/intc/loongarch_extioi: Add extioi virt extension definition
hw/loongarch/virt: Enable extioi virt extension
hw/loongarch/virt: Use MemTxAttrs interface for misc ops
include/hw/intc/loongarch_extioi.h | 21 ++++++
include/hw/loongarch/virt.h | 2 +
target/loongarch/cpu.h | 1 +
hw/intc/loongarch_extioi.c | 88 +++++++++++++++++++++-
hw/loongarch/virt.c | 116 +++++++++++++++++++++++++----
5 files changed, 210 insertions(+), 18 deletions(-)
--
2.34.1
