From: Auger Eric <eric.auger@redhat.com>
To: Keqian Zhu <zhukeqian1@huawei.com>,
eric.auger.pro@gmail.com, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu, will@kernel.org, joro@8bytes.org,
maz@kernel.org, robin.murphy@arm.com, alex.williamson@redhat.com
Cc: jean-philippe@linaro.org, vivek.gautam@arm.com, zhangfei.gao@linaro.org
Subject: Re: [PATCH v13 05/15] iommu/smmuv3: Get prepared for nested stage support
Date: Thu, 11 Feb 2021 18:36:01 +0100 [thread overview]
Message-ID: <0d949aef-6719-2ef4-f1cd-f323b4d4130b@redhat.com> (raw)
In-Reply-To: <118a047b-91f4-3c84-867f-6c0b89f9011e@huawei.com>
Hi Keqian,
On 2/2/21 8:14 AM, Keqian Zhu wrote:
> Hi Eric,
>
> On 2020/11/18 19:21, Eric Auger wrote:
>> When nested stage translation is setup, both s1_cfg and
>> s2_cfg are set.
>>
>> We introduce a new smmu domain abort field that will be set
>> upon guest stage1 configuration passing.
>>
>> arm_smmu_write_strtab_ent() is modified to write both stage
>> fields in the STE and deal with the abort field.
>>
>> In nested mode, only stage 2 is "finalized" as the host does
>> not own/configure the stage 1 context descriptor; guest does.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>> v10 -> v11:
>> - Fix an issue reported by Shameer when switching from with vSMMU
>> to without vSMMU. Despite the spec does not seem to mention it
>> seems to be needed to reset the 2 high 64b when switching from
>> S1+S2 cfg to S1 only. Especially dst[3] needs to be reset (S2TTB).
>> On some implementations, if the S2TTB is not reset, this causes
>> a C_BAD_STE error
>> ---
>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 64 +++++++++++++++++----
>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 +
>> 2 files changed, 56 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>> index 18ac5af1b284..412ea1bafa50 100644
>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>> @@ -1181,8 +1181,10 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>> * three cases at the moment:
>> *
>> * 1. Invalid (all zero) -> bypass/fault (init)
>> - * 2. Bypass/fault -> translation/bypass (attach)
>> - * 3. Translation/bypass -> bypass/fault (detach)
>> + * 2. Bypass/fault -> single stage translation/bypass (attach)
>> + * 3. Single or nested stage Translation/bypass -> bypass/fault (detach)
>> + * 4. S2 -> S1 + S2 (attach_pasid_table)
>> + * 5. S1 + S2 -> S2 (detach_pasid_table)
>
> The following line "BUG_ON(ste_live && !nested);" forbids this transform.
Yes as pointed out by Kunkun, there is always an abort in-between. I
will restore the original comment.
> And I have a look at the 6th patch, the transform seems S1 + S2 -> abort.
> So after detach, the status is not the same as that before attach. Does it
> match our expectation?
Indeed at detach time I think I should reset the abort() flag as this
latter is not imposed anymore by the guest.
Thanks!
Eric
>
>> *
>> * Given that we can't update the STE atomically and the SMMU
>> * doesn't read the thing in a defined order, that leaves us
>> @@ -1193,7 +1195,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>> * 3. Update Config, sync
>> */
>> u64 val = le64_to_cpu(dst[0]);
>> - bool ste_live = false;
>> + bool s1_live = false, s2_live = false, ste_live;
>> + bool abort, nested = false, translate = false;
>> struct arm_smmu_device *smmu = NULL;
>> struct arm_smmu_s1_cfg *s1_cfg;
>> struct arm_smmu_s2_cfg *s2_cfg;
>> @@ -1233,6 +1236,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>> default:
>> break;
>> }
>> + nested = s1_cfg->set && s2_cfg->set;
>> + translate = s1_cfg->set || s2_cfg->set;
>> }
>>
>> if (val & STRTAB_STE_0_V) {
>> @@ -1240,23 +1245,36 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>> case STRTAB_STE_0_CFG_BYPASS:
>> break;
>> case STRTAB_STE_0_CFG_S1_TRANS:
>> + s1_live = true;
>> + break;
>> case STRTAB_STE_0_CFG_S2_TRANS:
>> - ste_live = true;
>> + s2_live = true;
>> + break;
>> + case STRTAB_STE_0_CFG_NESTED:
>> + s1_live = true;
>> + s2_live = true;
>> break;
>> case STRTAB_STE_0_CFG_ABORT:
>> - BUG_ON(!disable_bypass);
>> break;
>> default:
>> BUG(); /* STE corruption */
>> }
>> }
>>
>> + ste_live = s1_live || s2_live;
>> +
>> /* Nuke the existing STE_0 value, as we're going to rewrite it */
>> val = STRTAB_STE_0_V;
>>
>> /* Bypass/fault */
>> - if (!smmu_domain || !(s1_cfg->set || s2_cfg->set)) {
>> - if (!smmu_domain && disable_bypass)
>> +
>> + if (!smmu_domain)
>> + abort = disable_bypass;
>> + else
>> + abort = smmu_domain->abort;
>> +
>> + if (abort || !translate) {
>> + if (abort)
>> val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
>> else
>> val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);
>> @@ -1274,8 +1292,16 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>> return;
>> }
>>
>> + BUG_ON(ste_live && !nested);
>> +
>> + if (ste_live) {
>> + /* First invalidate the live STE */
>> + dst[0] = cpu_to_le64(STRTAB_STE_0_CFG_ABORT);
>> + arm_smmu_sync_ste_for_sid(smmu, sid);
>> + }
>> +
> [...]
>
> Thanks,
> Keqian
>
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next prev parent reply other threads:[~2021-02-11 17:43 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 11:21 [PATCH v13 00/15] SMMUv3 Nested Stage Setup (IOMMU part) Eric Auger
2020-11-18 11:21 ` [PATCH v13 01/15] iommu: Introduce attach/detach_pasid_table API Eric Auger
2020-11-18 16:19 ` Jacob Pan
2020-11-19 17:02 ` Auger Eric
2021-02-01 11:27 ` Keqian Zhu
2021-02-01 17:18 ` Auger Eric
2020-11-18 11:21 ` [PATCH v13 02/15] iommu: Introduce bind/unbind_guest_msi Eric Auger
2021-02-01 11:52 ` Keqian Zhu
2021-02-12 8:55 ` Auger Eric
2021-02-18 8:43 ` Keqian Zhu
2021-02-18 10:35 ` Auger Eric
2020-11-18 11:21 ` [PATCH v13 03/15] iommu/arm-smmu-v3: Maintain a SID->device structure Eric Auger
2021-02-01 12:26 ` Keqian Zhu
2021-02-01 15:15 ` Jean-Philippe Brucker
2021-02-02 6:39 ` Keqian Zhu
2021-02-01 17:19 ` Auger Eric
2021-02-02 7:20 ` Keqian Zhu
2020-11-18 11:21 ` [PATCH v13 04/15] iommu/smmuv3: Allow s1 and s2 configs to coexist Eric Auger
2021-02-01 12:35 ` Keqian Zhu
2020-11-18 11:21 ` [PATCH v13 05/15] iommu/smmuv3: Get prepared for nested stage support Eric Auger
2020-11-19 3:59 ` kernel test robot
2020-12-03 12:32 ` Kunkun Jiang
2020-12-03 13:01 ` Auger Eric
2020-12-03 13:23 ` Kunkun Jiang
2020-12-09 14:26 ` Shameerali Kolothum Thodi
2021-02-02 7:14 ` Keqian Zhu
2021-02-11 17:36 ` Auger Eric [this message]
2020-11-18 11:21 ` [PATCH v13 06/15] iommu/smmuv3: Implement attach/detach_pasid_table Eric Auger
2021-02-02 8:03 ` Keqian Zhu
2021-02-11 17:35 ` Auger Eric
2020-11-18 11:21 ` [PATCH v13 07/15] iommu/smmuv3: Allow stage 1 invalidation with unmanaged ASIDs Eric Auger
2020-12-01 13:33 ` Xingang Wang
2020-12-01 13:58 ` Auger Eric
2020-12-02 12:59 ` Wang Xingang
2020-12-03 18:42 ` Shameerali Kolothum Thodi
2020-12-04 9:53 ` Jean-Philippe Brucker
2020-12-04 10:20 ` Shameerali Kolothum Thodi
2020-12-04 10:23 ` Auger Eric
2021-01-14 16:58 ` Auger Eric
2021-01-14 17:09 ` Shameerali Kolothum Thodi
2021-01-14 17:33 ` Jean-Philippe Brucker
2021-01-14 18:00 ` Auger Eric
2021-02-15 13:17 ` Auger Eric
2020-11-18 11:21 ` [PATCH v13 08/15] iommu/smmuv3: Implement cache_invalidate Eric Auger
2021-01-16 2:24 ` chenxiang (M)
2020-11-18 11:21 ` [PATCH v13 09/15] dma-iommu: Implement NESTED_MSI cookie Eric Auger
2020-11-18 11:21 ` [PATCH v13 10/15] iommu/smmuv3: Nested mode single MSI doorbell per domain enforcement Eric Auger
2020-11-18 11:21 ` [PATCH v13 11/15] iommu/smmuv3: Enforce incompatibility between nested mode and HW MSI regions Eric Auger
2020-11-18 11:21 ` [PATCH v13 12/15] iommu/smmuv3: Implement bind/unbind_guest_msi Eric Auger
2020-11-18 11:21 ` [PATCH v13 13/15] iommu/smmuv3: Report non recoverable faults Eric Auger
2020-11-18 11:21 ` [PATCH v13 14/15] iommu/smmuv3: Accept configs with more than one context descriptor Eric Auger
2020-11-18 11:21 ` [PATCH v13 15/15] iommu/smmuv3: Add PASID cache invalidation per PASID Eric Auger
2021-01-08 17:05 ` [PATCH v13 00/15] SMMUv3 Nested Stage Setup (IOMMU part) Shameerali Kolothum Thodi
2021-01-13 15:37 ` Auger Eric
2021-02-21 18:21 ` Auger Eric
2021-02-22 8:56 ` Shameerali Kolothum Thodi
2021-03-15 18:04 ` Krishna Reddy
2021-03-16 8:22 ` Auger Eric
2021-03-16 18:10 ` Krishna Reddy
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