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Re: [XEN PATCH v1] xen/arm : Add support for SMMUv3 driver
Hello, Rahul!
On 11/6/20 4:41 PM, Rahul Singh wrote:
Hello Oleksandr,
On 6 Nov 2020, at 2:22 pm, Oleksandr Andrushchenko
<Oleksandr_Andrushchenko@xxxxxxxx> wrote:
Hi, Rahul!
On 11/6/20 3:58 PM, Rahul Singh wrote:
Hello Oleksandr,
On 6 Nov 2020, at 1:00 pm, Oleksandr Andrushchenko
<Oleksandr_Andrushchenko@xxxxxxxx> wrote:
Hello, Rahul!
On 11/6/20 2:48 PM, Rahul Singh wrote:
Hello Oleksandr,
On 2 Nov 2020, at 10:12 am, Oleksandr Andrushchenko
<Oleksandr_Andrushchenko@xxxxxxxx> wrote:
Hi,
On 11/2/20 11:55 AM, Bertrand Marquis wrote:
Hi,
On 2 Nov 2020, at 05:55, Oleksandr Andrushchenko <andr2000@xxxxxxxxx> wrote:
Hi, Julien!
On 10/30/20 7:18 PM, Julien Grall wrote:
Hi Oleksandr,
On 30/10/2020 10:44, Oleksandr Andrushchenko wrote:
On 10/20/20 6:25 PM, Rahul Singh wrote:
Add support for ARM architected SMMUv3 implementations. It is based on
the Linux SMMUv3 driver.
Major differences between the Linux driver are as follows:
1. Only Stage-2 translation is supported as compared to the Linux driver
that supports both Stage-1 and Stage-2 translations.
First of all thank you for the efforts!
I tried the patch with QEMU and would like to know if my understanding correct
that this combination will not work as of now:
(XEN) SMMUv3: /smmuv3@9050000: SMMUv3: DT value = eventq
(XEN) Data Abort Trap. Syndrome=0x1940010
(XEN) Walking Hypervisor VA 0x40031000 on CPU0 via TTBR 0x00000000b8469000
(XEN) 0TH[0x0] = 0x00000000b8468f7f
[snip]
If this is expected then is there any plan to make QEMU work as well?
I see [1] says that "Only stage 1 and AArch64 PTW are supported." on QEMU side.
Just for clarication, you are trying to boot Xen on QEMU, right?
Exactly
You might be able to use the stage-1 page-tables to isolate each device in Xen.
However, I don't think you will be able to share the P2M because the
page-tables layout between stage-1 and stage-2 is different.
So, it is even more work then
Overall it would make more sense to spend some time adding proper support in
Qemu then trying to modify the driver to support Qemu right now.
We are interested in QEMU/SMMUv3 as a flexible platform for PCI passthrough
implementation, so it could allow testing different setups and configurations
with QEMU.
I would recommend to get the SMMU supporting supporting stage-2 page-tables.
You mean in QEMU?
See before.
Regardless that, I think Xen should be able to say the SMMU is not supported
rather than crashing.
Yes, that would be nice
Fully agree and we will look into that.
Anything you could share so that we could quickly reproduce your setup would be
more then great.
Nothing special,
qemu/aarch64-softmmu/qemu-system-aarch64 -machine type=virt -machine
virt,gic-version=2 \
-machine virtualization=true -cpu cortex-a57 -smp 4 -m 2048 -nic
user,hostfwd=tcp:127.0.0.1:2222-:22 \
-nographic -serial mon:stdio [..snip..]
I also set iommu to smmuv3 in my tests, QEMU emulator version 4.2.1
I just checked and confirmed that QEMU is booting with XEN SMMUv3 patch and XEN
is able to say SMMU translation is not supported. As XEN supports Stage-2
translation and QEMU supports Stage-1 only.
(XEN) SMMUv3: /smmuv3@9050000: SMMUv3: DT value = eventq
(XEN) SMMUv3: /smmuv3@9050000: IDR0.COHACC overridden by FW configuration
(false)
(XEN) SMMUv3: /smmuv3@9050000: no translation support!
(XEN) I/O virtualisation disabled
Only difference I observed is that you have to add option "-machine virt,iommu=smmuv3
“ when launching the QEMU.
I do use the option
I used "-machine virt,iommu=smmuv3 “ option while creating the virt-dtb and
while launching the QEMU.
I also observed the same error what you observed if I am not using the "-machine
virt,iommu=smmuv3 “ options when launching the QEMU so I thought this might be case
for you also but anyways you have use the options it might be other issue.
Hm, probably that was on my side as now I can see:
(XEN) SMMUv3: /smmuv3@9050000: SMMUv3: DT value = eventq
(XEN) SMMUv3: /smmuv3@9050000: IDR0.COHACC overridden by FW configuration
(false)
(XEN) SMMUv3: /smmuv3@9050000: no translation support!
(XEN) I/O virtualisation disabled
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Couldn't configure correctly all the IOMMUs.
(XEN) ****************************************
(XEN)
(XEN) Manual reset required ('noreboot' specified)
So, sorry for the noise, I might have misconfigured something it seems
When you say "Xen is booting" do you mean you see the same panic?
Yes I observe the same.
We have to decide now if for SMMUv3 there is no translation support do we have
to print the logs and move forward or as above return error to iommu_setup
that will cal panic().
I would allow Xen to boot further
Regards,
Rahul
Thank you,
Oleksandr
Please let me know if it also works for you.
Well, I should have reported that earlier that I do not use the staging Xen at
the moment,
it is 4.14.0. So, can this be a problem with that Xen version?
I don’t think so this is the problem with the XEN version.
Anyways, if it works with the staging then everything looks ok
Thank you,
Oleksandr
Regards
Bertrand
Cheers,
Thank you,
Oleksandr
Regards,
Rahul
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