* Re: [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device
2024-02-29 3:31 [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device Ethan Zhao
@ 2024-02-29 3:34 ` Ethan Zhao
2024-02-29 21:06 ` Bjorn Helgaas
2024-03-01 7:04 ` Ethan Zhao
2 siblings, 0 replies; 7+ messages in thread
From: Ethan Zhao @ 2024-02-29 3:34 UTC (permalink / raw)
To: baolu.lu, bhelgaas, robin.murphy, jgg
Cc: kevin.tian, dwmw2, will, lukas, yi.l.liu, dan.carpenter, iommu,
linux-kernel
On 2/29/2024 11:31 AM, Ethan Zhao wrote:
> The introduction of per iommu device rbtree also defines the lifetime of
> interoperation between iommu and devices, if the device has been released
> from device rbtree, no need to send ATS invalidation request to it anymore,
> thus avoid the possibility of later ITE fault to be triggered.
>
> This is part of the followup of prior proposed patchset
>
> https://do-db2.lkml.org/lkml/2024/2/22/350
>
> To make sure all the devTLB entries to be invalidated in the device release
> path, do implict invalidation by fapping the E bit of ATS control register.
> see PCIe spec v6.2, sec 10.3.7 implicit invalidation events.
>
> Fixes: 6f7db75e1c46 ("iommu/vt-d: Add second level page table interface")
> Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
> ---
> drivers/iommu/intel/iommu.c | 6 ++++++
> drivers/iommu/intel/pasid.c | 7 +++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 6743fe6c7a36..b85d88ccb4b0 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -1368,6 +1368,12 @@ static void iommu_disable_pci_caps(struct device_domain_info *info)
> pdev = to_pci_dev(info->dev);
>
> if (info->ats_enabled) {
> + pci_disable_ats(pdev);
> + /*
> + * flap the E bit of ATS control register to do implicit
> + * ATS invlidation, see PCIe spec v6.2, sec 10.3.7
> + */
> + pci_enable_ats(pdev, VTD_PAGE_SHIFT);
> pci_disable_ats(pdev);
> info->ats_enabled = 0;
> domain_update_iotlb(info->domain);
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index 108158e2b907..5f13e017a12c 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -215,6 +215,13 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
> return;
>
> sid = info->bus << 8 | info->devfn;
> + /*
> + * If device has been released from rbtree, no need to send ATS
> + * Invalidation request anymore, that could cause ITE fault.
> + */
> + if (!device_rbtree_find(iommu, sid))
> + return;
> +
> qdep = info->ats_qdep;
> pfsid = info->pfsid;
>
This patch based on Baolu's per iommu device rbtree patchset
https://github.com/LuBaolu/intel-iommu/commits/rbtree-for-device-info-v2
Thanks,
Ethan
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device
2024-02-29 3:31 [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device Ethan Zhao
2024-02-29 3:34 ` Ethan Zhao
@ 2024-02-29 21:06 ` Bjorn Helgaas
2024-03-01 1:50 ` Ethan Zhao
2024-03-01 7:04 ` Ethan Zhao
2 siblings, 1 reply; 7+ messages in thread
From: Bjorn Helgaas @ 2024-02-29 21:06 UTC (permalink / raw)
To: Ethan Zhao
Cc: baolu.lu, bhelgaas, robin.murphy, jgg, kevin.tian, dwmw2, will,
lukas, yi.l.liu, dan.carpenter, iommu, linux-kernel
On Wed, Feb 28, 2024 at 10:31:38PM -0500, Ethan Zhao wrote:
> The introduction of per iommu device rbtree also defines the lifetime of
> interoperation between iommu and devices, if the device has been released
> from device rbtree, no need to send ATS invalidation request to it anymore,
> thus avoid the possibility of later ITE fault to be triggered.
>
> This is part of the followup of prior proposed patchset
>
> https://do-db2.lkml.org/lkml/2024/2/22/350
Please use https://lore.kernel.org/ URLs instead. This one looks like
https://lore.kernel.org/r/20240222090251.2849702-1-haifeng.zhao@linux.intel.com/
> To make sure all the devTLB entries to be invalidated in the device release
> path, do implict invalidation by fapping the E bit of ATS control register.
> see PCIe spec v6.2, sec 10.3.7 implicit invalidation events.
s/implict/implicit/
s/fapping/?/ (no idea :) "flipping"? Oh, probably "flapping" per the
comment below. But I think "flapping" is ambiguous; "setting" would be
better)
s/v6.2/r6.2/ (also below in comment)
> Fixes: 6f7db75e1c46 ("iommu/vt-d: Add second level page table interface")
> Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
> ---
> drivers/iommu/intel/iommu.c | 6 ++++++
> drivers/iommu/intel/pasid.c | 7 +++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 6743fe6c7a36..b85d88ccb4b0 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -1368,6 +1368,12 @@ static void iommu_disable_pci_caps(struct device_domain_info *info)
> pdev = to_pci_dev(info->dev);
>
> if (info->ats_enabled) {
> + pci_disable_ats(pdev);
> + /*
> + * flap the E bit of ATS control register to do implicit
> + * ATS invlidation, see PCIe spec v6.2, sec 10.3.7
s/invlidation/invalidation/
I would put the comment above the pci_disable_ats(), so it looks like
this:
/* comment ... */
pci_disable_ats(pdev);
pci_enable_ats(pdev, VTD_PAGE_SHIFT);
pci_disable_ats(pdev);
because the spec says the E field must change from Clear to Set to
cause invalidation of all ATC entries, so it's important to see that
we clear E first, then set it.
> + */
> + pci_enable_ats(pdev, VTD_PAGE_SHIFT);
> pci_disable_ats(pdev);
> info->ats_enabled = 0;
> domain_update_iotlb(info->domain);
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index 108158e2b907..5f13e017a12c 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -215,6 +215,13 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
> return;
>
> sid = info->bus << 8 | info->devfn;
> + /*
> + * If device has been released from rbtree, no need to send ATS
> + * Invalidation request anymore, that could cause ITE fault.
> + */
> + if (!device_rbtree_find(iommu, sid))
> + return;
> +
> qdep = info->ats_qdep;
> pfsid = info->pfsid;
>
> --
> 2.31.1
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device
2024-02-29 21:06 ` Bjorn Helgaas
@ 2024-03-01 1:50 ` Ethan Zhao
2024-03-01 21:56 ` Bjorn Helgaas
0 siblings, 1 reply; 7+ messages in thread
From: Ethan Zhao @ 2024-03-01 1:50 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: baolu.lu, bhelgaas, robin.murphy, jgg, kevin.tian, dwmw2, will,
lukas, yi.l.liu, dan.carpenter, iommu, linux-kernel
On 3/1/2024 5:06 AM, Bjorn Helgaas wrote:
> On Wed, Feb 28, 2024 at 10:31:38PM -0500, Ethan Zhao wrote:
>> The introduction of per iommu device rbtree also defines the lifetime of
>> interoperation between iommu and devices, if the device has been released
>> from device rbtree, no need to send ATS invalidation request to it anymore,
>> thus avoid the possibility of later ITE fault to be triggered.
>>
>> This is part of the followup of prior proposed patchset
>>
>> https://do-db2.lkml.org/lkml/2024/2/22/350
> Please use https://lore.kernel.org/ URLs instead. This one looks like
> https://lore.kernel.org/r/20240222090251.2849702-1-haifeng.zhao@linux.intel.com/
>
>> To make sure all the devTLB entries to be invalidated in the device release
>> path, do implict invalidation by fapping the E bit of ATS control register.
>> see PCIe spec v6.2, sec 10.3.7 implicit invalidation events.
> s/implict/implicit/
>
> s/fapping/?/ (no idea :) "flipping"? Oh, probably "flapping" per the
> comment below. But I think "flapping" is ambiguous; "setting" would be
> better)
Yup, like the memory bit flipping, no idea what is the right word,
setting one bit to 0, then 1, then back to 0. perhaps details the
setting action 0-->1-->0 ?
> s/v6.2/r6.2/ (also below in comment)
got it.
>
>> Fixes: 6f7db75e1c46 ("iommu/vt-d: Add second level page table interface")
>> Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
>> ---
>> drivers/iommu/intel/iommu.c | 6 ++++++
>> drivers/iommu/intel/pasid.c | 7 +++++++
>> 2 files changed, 13 insertions(+)
>>
>> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
>> index 6743fe6c7a36..b85d88ccb4b0 100644
>> --- a/drivers/iommu/intel/iommu.c
>> +++ b/drivers/iommu/intel/iommu.c
>> @@ -1368,6 +1368,12 @@ static void iommu_disable_pci_caps(struct device_domain_info *info)
>> pdev = to_pci_dev(info->dev);
>>
>> if (info->ats_enabled) {
>> + pci_disable_ats(pdev);
>> + /*
>> + * flap the E bit of ATS control register to do implicit
>> + * ATS invlidation, see PCIe spec v6.2, sec 10.3.7
> s/invlidation/invalidation/
>
> I would put the comment above the pci_disable_ats(), so it looks like
> this:
>
> /* comment ... */
> pci_disable_ats(pdev);
> pci_enable_ats(pdev, VTD_PAGE_SHIFT);
>
> pci_disable_ats(pdev);
>
> because the spec says the E field must change from Clear to Set to
> cause invalidation of all ATC entries, so it's important to see that
> we clear E first, then set it.
Great, will correct.
Thanks,
Ethan
>
>> + */
>> + pci_enable_ats(pdev, VTD_PAGE_SHIFT);
>> pci_disable_ats(pdev);
>> info->ats_enabled = 0;
>> domain_update_iotlb(info->domain);
>> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
>> index 108158e2b907..5f13e017a12c 100644
>> --- a/drivers/iommu/intel/pasid.c
>> +++ b/drivers/iommu/intel/pasid.c
>> @@ -215,6 +215,13 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
>> return;
>>
>> sid = info->bus << 8 | info->devfn;
>> + /*
>> + * If device has been released from rbtree, no need to send ATS
>> + * Invalidation request anymore, that could cause ITE fault.
>> + */
>> + if (!device_rbtree_find(iommu, sid))
>> + return;
>> +
>> qdep = info->ats_qdep;
>> pfsid = info->pfsid;
>>
>> --
>> 2.31.1
>>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device
2024-03-01 1:50 ` Ethan Zhao
@ 2024-03-01 21:56 ` Bjorn Helgaas
2024-03-04 1:52 ` Ethan Zhao
0 siblings, 1 reply; 7+ messages in thread
From: Bjorn Helgaas @ 2024-03-01 21:56 UTC (permalink / raw)
To: Ethan Zhao
Cc: baolu.lu, bhelgaas, robin.murphy, jgg, kevin.tian, dwmw2, will,
lukas, yi.l.liu, dan.carpenter, iommu, linux-kernel
On Fri, Mar 01, 2024 at 09:50:36AM +0800, Ethan Zhao wrote:
> On 3/1/2024 5:06 AM, Bjorn Helgaas wrote:
> > On Wed, Feb 28, 2024 at 10:31:38PM -0500, Ethan Zhao wrote:
> > > The introduction of per iommu device rbtree also defines the lifetime of
> > > interoperation between iommu and devices, if the device has been released
> > > from device rbtree, no need to send ATS invalidation request to it anymore,
> > > thus avoid the possibility of later ITE fault to be triggered.
> > >
> > > This is part of the followup of prior proposed patchset
> > >
> > > https://do-db2.lkml.org/lkml/2024/2/22/350
> > Please use https://lore.kernel.org/ URLs instead. This one looks like
> > https://lore.kernel.org/r/20240222090251.2849702-1-haifeng.zhao@linux.intel.com/
> >
> > > To make sure all the devTLB entries to be invalidated in the device release
> > > path, do implict invalidation by fapping the E bit of ATS control register.
> > > see PCIe spec v6.2, sec 10.3.7 implicit invalidation events.
> > s/implict/implicit/
> >
> > s/fapping/?/ (no idea :) "flipping"? Oh, probably "flapping" per the
> > comment below. But I think "flapping" is ambiguous; "setting" would be
> > better)
>
> Yup, like the memory bit flipping, no idea what is the right word,
> setting one bit to 0, then 1, then back to 0. perhaps details the
> setting action 0-->1-->0 ?
In PCIe spec-speak, "Set" means "assign 1 to this", and "Clear" means
"assign 0 to this".
Maybe you could copy the spec language like this:
Invalidate all ATC entries by changing the E field in the ATS
Capability from Clear to Set, which causes an implicit invalidation
event.
Bjorn
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device
2024-03-01 21:56 ` Bjorn Helgaas
@ 2024-03-04 1:52 ` Ethan Zhao
0 siblings, 0 replies; 7+ messages in thread
From: Ethan Zhao @ 2024-03-04 1:52 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: baolu.lu, bhelgaas, robin.murphy, jgg, kevin.tian, dwmw2, will,
lukas, yi.l.liu, dan.carpenter, iommu, linux-kernel
On 3/2/2024 5:56 AM, Bjorn Helgaas wrote:
> On Fri, Mar 01, 2024 at 09:50:36AM +0800, Ethan Zhao wrote:
>> On 3/1/2024 5:06 AM, Bjorn Helgaas wrote:
>>> On Wed, Feb 28, 2024 at 10:31:38PM -0500, Ethan Zhao wrote:
>>>> The introduction of per iommu device rbtree also defines the lifetime of
>>>> interoperation between iommu and devices, if the device has been released
>>>> from device rbtree, no need to send ATS invalidation request to it anymore,
>>>> thus avoid the possibility of later ITE fault to be triggered.
>>>>
>>>> This is part of the followup of prior proposed patchset
>>>>
>>>> https://do-db2.lkml.org/lkml/2024/2/22/350
>>> Please use https://lore.kernel.org/ URLs instead. This one looks like
>>> https://lore.kernel.org/r/20240222090251.2849702-1-haifeng.zhao@linux.intel.com/
>>>
>>>> To make sure all the devTLB entries to be invalidated in the device release
>>>> path, do implict invalidation by fapping the E bit of ATS control register.
>>>> see PCIe spec v6.2, sec 10.3.7 implicit invalidation events.
>>> s/implict/implicit/
>>>
>>> s/fapping/?/ (no idea :) "flipping"? Oh, probably "flapping" per the
>>> comment below. But I think "flapping" is ambiguous; "setting" would be
>>> better)
>> Yup, like the memory bit flipping, no idea what is the right word,
>> setting one bit to 0, then 1, then back to 0. perhaps details the
>> setting action 0-->1-->0 ?
> In PCIe spec-speak, "Set" means "assign 1 to this", and "Clear" means
> "assign 0 to this".
>
> Maybe you could copy the spec language like this:
>
> Invalidate all ATC entries by changing the E field in the ATS
> Capability from Clear to Set, which causes an implicit invalidation
> event.
Fair enough.
Thanks,
Ethan
>
> Bjorn
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device
2024-02-29 3:31 [PATCH] iommu/vt-d: avoid sending explicit ATS invalidation request to released device Ethan Zhao
2024-02-29 3:34 ` Ethan Zhao
2024-02-29 21:06 ` Bjorn Helgaas
@ 2024-03-01 7:04 ` Ethan Zhao
2 siblings, 0 replies; 7+ messages in thread
From: Ethan Zhao @ 2024-03-01 7:04 UTC (permalink / raw)
To: baolu.lu, bhelgaas, robin.murphy, jgg
Cc: kevin.tian, dwmw2, will, lukas, yi.l.liu, dan.carpenter, iommu,
linux-kernel
On 2/29/2024 11:31 AM, Ethan Zhao wrote:
> The introduction of per iommu device rbtree also defines the lifetime of
> interoperation between iommu and devices, if the device has been released
> from device rbtree, no need to send ATS invalidation request to it anymore,
> thus avoid the possibility of later ITE fault to be triggered.
>
> This is part of the followup of prior proposed patchset
>
> https://do-db2.lkml.org/lkml/2024/2/22/350
>
> To make sure all the devTLB entries to be invalidated in the device release
> path, do implict invalidation by fapping the E bit of ATS control register.
> see PCIe spec v6.2, sec 10.3.7 implicit invalidation events.
>
> Fixes: 6f7db75e1c46 ("iommu/vt-d: Add second level page table interface")
> Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
> ---
> drivers/iommu/intel/iommu.c | 6 ++++++
> drivers/iommu/intel/pasid.c | 7 +++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 6743fe6c7a36..b85d88ccb4b0 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -1368,6 +1368,12 @@ static void iommu_disable_pci_caps(struct device_domain_info *info)
> pdev = to_pci_dev(info->dev);
>
> if (info->ats_enabled) {
> + pci_disable_ats(pdev);
> + /*
> + * flap the E bit of ATS control register to do implicit
> + * ATS invlidation, see PCIe spec v6.2, sec 10.3.7
> + */
> + pci_enable_ats(pdev, VTD_PAGE_SHIFT);
> pci_disable_ats(pdev);
> info->ats_enabled = 0;
> domain_update_iotlb(info->domain);
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index 108158e2b907..5f13e017a12c 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -215,6 +215,13 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
> return;
>
> sid = info->bus << 8 | info->devfn;
> + /*
> + * If device has been released from rbtree, no need to send ATS
> + * Invalidation request anymore, that could cause ITE fault.
> + */
> + if (!device_rbtree_find(iommu, sid))
> + return;
> +
> qdep = info->ats_qdep;
> pfsid = info->pfsid;
>
Given maintainer is going to pick up patchset
https://lore.kernel.org/lkml/2d1788da-521c-4531-a159-81d2fb801d6c@linux.intel.com/T/
and this one is mutually exclusive with it, suspend.
Thanks,
Ethan
^ permalink raw reply [flat|nested] 7+ messages in thread