linux-kernel - RE: [PATCH v13 07/15] iommu/smmuv3: Allow stage 1 invalidation with unmanaged ASIDs

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Date:   Thu, 3 Dec 2020 18:42:57 +0000
From:   Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>
To:     Auger Eric <eric.auger@...hat.com>,
        wangxingang <wangxingang5@...wei.com>
CC:     Xieyingtai <xieyingtai@...wei.com>,
        "jean-philippe@...aro.org" <jean-philippe@...aro.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "maz@...nel.org" <maz@...nel.org>,
        "joro@...tes.org" <joro@...tes.org>,
        "will@...nel.org" <will@...nel.org>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "vivek.gautam@....com" <vivek.gautam@....com>,
        "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
        "zhangfei.gao@...aro.org" <zhangfei.gao@...aro.org>,
        "robin.murphy@....com" <robin.murphy@....com>,
        "kvmarm@...ts.cs.columbia.edu" <kvmarm@...ts.cs.columbia.edu>,
        "eric.auger.pro@...il.com" <eric.auger.pro@...il.com>,
        "Zengtao (B)" <prime.zeng@...ilicon.com>,
        qubingbing <qubingbing@...ilicon.com>
Subject: RE: [PATCH v13 07/15] iommu/smmuv3: Allow stage 1 invalidation with
 unmanaged ASIDs

Hi Eric,

> -----Original Message-----
> From: kvmarm-bounces@...ts.cs.columbia.edu
> [mailto:kvmarm-bounces@...ts.cs.columbia.edu] On Behalf Of Auger Eric
> Sent: 01 December 2020 13:59
> To: wangxingang <wangxingang5@...wei.com>
> Cc: Xieyingtai <xieyingtai@...wei.com>; jean-philippe@...aro.org;
> kvm@...r.kernel.org; maz@...nel.org; joro@...tes.org; will@...nel.org;
> iommu@...ts.linux-foundation.org; linux-kernel@...r.kernel.org;
> vivek.gautam@....com; alex.williamson@...hat.com;
> zhangfei.gao@...aro.org; robin.murphy@....com;
> kvmarm@...ts.cs.columbia.edu; eric.auger.pro@...il.com
> Subject: Re: [PATCH v13 07/15] iommu/smmuv3: Allow stage 1 invalidation with
> unmanaged ASIDs
> 
> Hi Xingang,
> 
> On 12/1/20 2:33 PM, Xingang Wang wrote:
> > Hi Eric
> >
> > On  Wed, 18 Nov 2020 12:21:43, Eric Auger wrote:
> >> @@ -1710,7 +1710,11 @@ static void arm_smmu_tlb_inv_context(void
> *cookie)
> >> 	 * insertion to guarantee those are observed before the TLBI. Do be
> >> 	 * careful, 007.
> >> 	 */
> >> -	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> >> +	if (ext_asid >= 0) { /* guest stage 1 invalidation */
> >> +		cmd.opcode	= CMDQ_OP_TLBI_NH_ASID;
> >> +		cmd.tlbi.asid	= ext_asid;
> >> +		cmd.tlbi.vmid	= smmu_domain->s2_cfg.vmid;
> >> +	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> >
> > Found a problem here, the cmd for guest stage 1 invalidation is built,
> > but it is not delivered to smmu.
> >
> 
> Thank you for the report. I will fix that soon. With that fixed, have
> you been able to run vSVA on top of the series. Do you need other stuff
> to be fixed at SMMU level? 

I am seeing another issue with this series. This is when you have the vSMMU
in non-strict mode(iommu.strict=0). Any network pass-through dev with iperf run 
will be enough to reproduce the issue. It may randomly stop/hang.

It looks like the .flush_iotlb_all from guest is not propagated down to the host
correctly. I have a temp hack to fix this in Qemu wherein CMDQ_OP_TLBI_NH_ASID
will result in a CACHE_INVALIDATE with IOMMU_INV_GRANU_PASID flag and archid
set.

Please take a look and let me know. 

As I am going to respin soon, please let me
> know what is the best branch to rebase to alleviate your integration.

Please find the latest kernel and Qemu branch with vSVA support added here,

https://github.com/hisilicon/kernel-dev/tree/5.10-rc4-2stage-v13-vsva
https://github.com/hisilicon/qemu/tree/v5.2.0-rc1-2stage-rfcv7-vsva

I have done some basic minimum vSVA tests on a HiSilicon D06 board with
a zip dev that supports STALL. All looks good so far apart from the issues
that have been already reported/discussed.

The kernel branch is actually a rebase of sva/uacce related patches from a
Linaro branch here,

https://github.com/Linaro/linux-kernel-uadk/tree/uacce-devel-5.10

I think going forward it will be good(if possible) to respin your series on top of
a sva branch with STALL/PRI support added. 

Hi Jean/zhangfei,
Is it possible to have a branch with minimum required SVA/UACCE related patches
that are already public and can be a "stable" candidate for future respin of Eric's series?
Please share your thoughts.

Thanks,
Shameer 

> Best Regards
> 
> Eric
> 
> _______________________________________________
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> kvmarm@...ts.cs.columbia.edu
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