From: Steven Price <steven.price@arm.com>
To: Jon Nettleton <jon@solid-run.com>,
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
iommu@lists.linux-foundation.org, Linuxarm <linuxarm@huawei.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
joro@8bytes.org, Robin Murphy <robin.murphy@arm.com>,
wanghuiqiang <wanghuiqiang@huawei.com>,
Hanjun Guo <guohanjun@huawei.com>,
Sami.Mujawar@arm.com, eric.auger@redhat.com,
yangyicong <yangyicong@huawei.com>
Subject: Re: [PATCH v5 7/8] iommu/arm-smmu: Get associated RMR info and install bypass SMR
Date: Thu, 3 Jun 2021 12:27:30 +0100 [thread overview]
Message-ID: <32dc72fa-534a-7eb4-dfcc-9bc244845a28@arm.com> (raw)
In-Reply-To: <CABdtJHvo7HZ0R1EzLrN2gVKfgcBWz5YRU-KSg==xvHR-01KWkw@mail.gmail.com>
On 03/06/2021 09:52, Jon Nettleton wrote:
> On Mon, May 24, 2021 at 1:04 PM Shameer Kolothum
> <shameerali.kolothum.thodi@huawei.com> wrote:
>>
>> From: Jon Nettleton <jon@solid-run.com>
>>
>> Check if there is any RMR info associated with the devices behind
>> the SMMU and if any, install bypass SMRs for them. This is to
>> keep any ongoing traffic associated with these devices alive
>> when we enable/reset SMMU during probe().
>>
>> Signed-off-by: Jon Nettleton <jon@solid-run.com>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>> ---
>> drivers/iommu/arm/arm-smmu/arm-smmu.c | 65 +++++++++++++++++++++++++++
>> 1 file changed, 65 insertions(+)
>>
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> index 6f72c4d208ca..56db3d3238fc 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> @@ -2042,6 +2042,67 @@ err_reset_platform_ops: __maybe_unused;
>> return err;
>> }
>>
>> +static void arm_smmu_rmr_install_bypass_smr(struct arm_smmu_device *smmu)
>> +{
>> + struct list_head rmr_list;
>> + struct iommu_resv_region *e;
>> + int i, cnt = 0;
>> + u32 smr;
>> + u32 reg;
>> +
>> + INIT_LIST_HEAD(&rmr_list);
>> + if (iommu_dma_get_rmrs(dev_fwnode(smmu->dev), &rmr_list))
>> + return;
>> +
>> + reg = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_sCR0);
>> +
>> + if ((reg & ARM_SMMU_sCR0_USFCFG) && !(reg & ARM_SMMU_sCR0_CLIENTPD)) {
>> + /*
>> + * SMMU is already enabled and disallowing bypass, so preserve
>> + * the existing SMRs
>> + */
>> + for (i = 0; i < smmu->num_mapping_groups; i++) {
>> + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i));
>> + if (!FIELD_GET(ARM_SMMU_SMR_VALID, smr))
>> + continue;
>> + smmu->smrs[i].id = FIELD_GET(ARM_SMMU_SMR_ID, smr);
>> + smmu->smrs[i].mask = FIELD_GET(ARM_SMMU_SMR_MASK, smr);
>> + smmu->smrs[i].valid = true;
>> + }
>> + }
>> +
>> + list_for_each_entry(e, &rmr_list, list) {
>> + u32 sid = e->fw_data.rmr.sid;
>> +
>> + i = arm_smmu_find_sme(smmu, sid, ~0);
>> + if (i < 0)
>> + continue;
>> + if (smmu->s2crs[i].count == 0) {
>> + smmu->smrs[i].id = sid;
>> + smmu->smrs[i].mask = ~0;
Looking at this code again, that mask looks wrong! According to the SMMU
spec MASK[i]==1 means ID[i] is ignored. I.e. this means completely
ignore the ID...
I'm not at all sure why they designed the hardware that way round.
>> + smmu->smrs[i].valid = true;
>> + }
>> + smmu->s2crs[i].count++;
>> + smmu->s2crs[i].type = S2CR_TYPE_BYPASS;
>> + smmu->s2crs[i].privcfg = S2CR_PRIVCFG_DEFAULT;
>> + smmu->s2crs[i].cbndx = 0xff;
>> +
>> + cnt++;
>> + }
>> +
>> + if ((reg & ARM_SMMU_sCR0_USFCFG) && !(reg & ARM_SMMU_sCR0_CLIENTPD)) {
>> + /* Remove the valid bit for unused SMRs */
>> + for (i = 0; i < smmu->num_mapping_groups; i++) {
>> + if (smmu->s2crs[i].count == 0)
>> + smmu->smrs[i].valid = false;
>> + }
>> + }
>> +
>> + dev_notice(smmu->dev, "\tpreserved %d boot mapping%s\n", cnt,
>> + cnt == 1 ? "" : "s");
>> + iommu_dma_put_rmrs(dev_fwnode(smmu->dev), &rmr_list);
>> +}
>> +
>> static int arm_smmu_device_probe(struct platform_device *pdev)
>> {
>> struct resource *res;
>> @@ -2168,6 +2229,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>> }
>>
>> platform_set_drvdata(pdev, smmu);
>> +
>> + /* Check for RMRs and install bypass SMRs if any */
>> + arm_smmu_rmr_install_bypass_smr(smmu);
>> +
>> arm_smmu_device_reset(smmu);
>> arm_smmu_test_smr_masks(smmu);
>>
>> --
>> 2.17.1
>>
>
> Shameer and Robin
>
> I finally got around to updating edk2 and the HoneyComb IORT tables to
> reflect the new standards.
> Out of the box the new patchset was generating errors immediatly after
> the smmu bringup.
>
> arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x2080000140,
> fsynr=0x1d0040, cbfrsynra=0x4000, cb=0
>
> These errors were generated even with disable_bypass=0
>
> I tracked down the issue to
>
> This code is skipped as Robin said would be correct
If you're skipping the first bit of code, then that (hopefully) means
that the SMMU is disabled...
>> + if ((reg & ARM_SMMU_sCR0_USFCFG) && !(reg & ARM_SMMU_sCR0_CLIENTPD)) {
>> + /*
>> + * SMMU is already enabled and disallowing bypass, so preserve
>> + * the existing SMRs
>> + */
>> + for (i = 0; i < smmu->num_mapping_groups; i++) {
>> + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i));
>> + if (!FIELD_GET(ARM_SMMU_SMR_VALID, smr))
>> + continue;
>> + smmu->smrs[i].id = FIELD_GET(ARM_SMMU_SMR_ID, smr);
>> + smmu->smrs[i].mask = FIELD_GET(ARM_SMMU_SMR_MASK, smr);
>> + smmu->smrs[i].valid = true;
>> + }[ 2.707729] arm-smmu: setting up rmr list on 0x4000
> [ 2.712598] arm-smmu: s2crs count is 0 smrs index 0x0
> [ 2.717638] arm-smmu: s2crs count is 0 smrs id is 0x4000
> [ 2.722939] arm-smmu: s2crs count is 0 smrs mask is 0x8000
> [ 2.728417] arm-smmu arm-smmu.0.auto: preserved 1 boot mapping
>
>> + }
>
> Then this code block was hit which is correct
>
>> + if (smmu->s2crs[i].count == 0) {
>> + smmu->smrs[i].id = sid;
>> + smmu->smrs[i].mask = ~0;
>> + smmu->smrs[i].valid = true;
>> + }
>
> The mask was causing the issue. If I think ammended that segment to read
> the mask as setup by the hardware everything was back to functioning both
> with and without disable_bypass set.
...so reading a mask from it doesn't sounds quite right.
Can you have a go with a corrected mask of '0' rather than all-1s and
see if that helps? My guess is that the mask of ~0 was causing multiple
matches in the SMRs which is 'UNPREDICTABLE'.
Sadly in my test setup there's only the one device behind the SMMU so
I didn't spot this (below patch works for me, but that's not saying
much).
Steve
--->8---
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 56db3d3238fc..44831d0c78e4 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -2079,7 +2079,7 @@ static void arm_smmu_rmr_install_bypass_smr(struct arm_smmu_device *smmu)
continue;
if (smmu->s2crs[i].count == 0) {
smmu->smrs[i].id = sid;
- smmu->smrs[i].mask = ~0;
+ smmu->smrs[i].mask = 0;
smmu->smrs[i].valid = true;
}
smmu->s2crs[i].count++;
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-06-03 11:29 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-24 11:02 [PATCH v5 0/8] ACPI/IORT: Support for IORT RMR node Shameer Kolothum
2021-05-24 11:02 ` [PATCH v5 1/8] ACPI/IORT: Add support for RMR node parsing Shameer Kolothum
2021-06-14 11:14 ` Robin Murphy
2021-06-14 12:37 ` Shameerali Kolothum Thodi
2021-05-24 11:02 ` [PATCH v5 2/8] iommu/dma: Introduce generic helper to retrieve RMR info Shameer Kolothum
2021-05-24 15:35 ` kernel test robot
2021-05-24 11:02 ` [PATCH v5 3/8] ACPI/IORT: Add a helper to retrieve RMR memory regions Shameer Kolothum
2021-05-26 7:53 ` Laurentiu Tudor
2021-05-26 16:36 ` Shameerali Kolothum Thodi
2021-05-26 17:11 ` Laurentiu Tudor
2021-06-03 12:27 ` Jon Nettleton
2021-06-03 12:32 ` Laurentiu Tudor
2021-05-27 4:25 ` Jon Nettleton
2021-06-14 10:35 ` Robin Murphy
2021-06-14 11:23 ` Robin Murphy
2021-06-14 12:49 ` Shameerali Kolothum Thodi
2021-06-29 17:34 ` Jon Nettleton
2021-07-04 7:38 ` Jon Nettleton
2021-07-05 9:10 ` Shameerali Kolothum Thodi
2021-05-24 11:02 ` [PATCH v5 4/8] iommu/arm-smmu-v3: Introduce strtab init helper Shameer Kolothum
2021-05-24 11:02 ` [PATCH v5 5/8] iommu/arm-smmu-v3: Add bypass flag to arm_smmu_write_strtab_ent() Shameer Kolothum
2021-06-14 10:23 ` Robin Murphy
2021-06-14 12:51 ` Shameerali Kolothum Thodi
2021-05-24 11:02 ` [PATCH v5 6/8] iommu/arm-smmu-v3: Get associated RMR info and install Shameer Kolothum
2021-06-14 10:15 ` Robin Murphy
2021-05-24 11:02 ` [PATCH v5 7/8] iommu/arm-smmu: Get associated RMR info and install bypass SMR Shameer Kolothum
2021-06-03 8:52 ` Jon Nettleton
2021-06-03 11:27 ` Steven Price [this message]
2021-06-03 11:51 ` Jon Nettleton
2021-06-13 7:40 ` Jon Nettleton
2021-06-14 9:23 ` Robin Murphy
2021-06-14 10:06 ` Robin Murphy
2021-06-14 16:51 ` Shameerali Kolothum Thodi
2021-06-15 8:02 ` Jon Nettleton
2021-06-29 7:03 ` Jon Nettleton
2021-06-29 13:22 ` Robin Murphy
2021-06-29 16:25 ` Jon Nettleton
2021-06-30 8:50 ` Shameerali Kolothum Thodi
2021-05-24 11:02 ` [PATCH v5 8/8] iommu/dma: Reserve any RMR regions associated with a dev Shameer Kolothum
2021-05-24 15:18 ` [PATCH v5 0/8] ACPI/IORT: Support for IORT RMR node Steven Price
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=32dc72fa-534a-7eb4-dfcc-9bc244845a28@arm.com \
--to=steven.price@arm.com \
--cc=Sami.Mujawar@arm.com \
--cc=eric.auger@redhat.com \
--cc=guohanjun@huawei.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jon@solid-run.com \
--cc=joro@8bytes.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linuxarm@huawei.com \
--cc=lorenzo.pieralisi@arm.com \
--cc=robin.murphy@arm.com \
--cc=shameerali.kolothum.thodi@huawei.com \
--cc=wanghuiqiang@huawei.com \
--cc=yangyicong@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).