Hi, Robin
Thank you for the comment.
在 2021年01月13日 01:29, Robin Murphy 写道:
> On 2021-01-05 07:52, lijiang wrote:
>> 在 2021年01月05日 11:55, lijiang 写道:
>>> Hi,
>>>
>>> Also add Joerg to cc list.
>>>
>>
>> Also add more people to cc list, Jerry Snitselaar and Tom Lendacky.
>>
>> Thanks.
>>
>>> Thanks.
>>> Lianbo
>>> 在 2020年12月26日 13:39, Lianbo Jiang 写道:
>>>> Currently, because domain attach allows to be deferred from iommu
>>>> driver to device driver, and when iommu initializes, the devices
>>>> on the bus will be scanned and the default groups will be allocated.
>>>>
>>>> Due to the above changes, some devices could be added to the same
>>>> group as below:
>>>>
>>>> [ 3.859417] pci 0000:01:00.0: Adding to iommu group 16
>>>> [ 3.864572] pci 0000:01:00.1: Adding to iommu group 16
>>>> [ 3.869738] pci 0000:02:00.0: Adding to iommu group 17
>>>> [ 3.874892] pci 0000:02:00.1: Adding to iommu group 17
>>>>
>>>> But when attaching these devices, it doesn't allow that a group has
>>>> more than one device, otherwise it will return an error. This conflicts
>>>> with the deferred attaching. Unfortunately, it has two devices in the
>>>> same group for my side, for example:
>>>>
>>>> [ 9.627014] iommu_group_device_count(): device name[0]:0000:01:00.0
>>>> [ 9.633545] iommu_group_device_count(): device name[1]:0000:01:00.1
>>>> ...
>>>> [ 10.255609] iommu_group_device_count(): device name[0]:0000:02:00.0
>>>> [ 10.262144] iommu_group_device_count(): device name[1]:0000:02:00.1
>>>>
>>>> Finally, which caused the failure of tg3 driver when tg3 driver calls
>>>> the dma_alloc_coherent() to allocate coherent memory in the tg3_test_dma().
>>>>
>>>> [ 9.660310] tg3 0000:01:00.0: DMA engine test failed, aborting
>>>> [ 9.754085] tg3: probe of 0000:01:00.0 failed with error -12
>>>> [ 9.997512] tg3 0000:01:00.1: DMA engine test failed, aborting
>>>> [ 10.043053] tg3: probe of 0000:01:00.1 failed with error -12
>>>> [ 10.288905] tg3 0000:02:00.0: DMA engine test failed, aborting
>>>> [ 10.334070] tg3: probe of 0000:02:00.0 failed with error -12
>>>> [ 10.578303] tg3 0000:02:00.1: DMA engine test failed, aborting
>>>> [ 10.622629] tg3: probe of 0000:02:00.1 failed with error -12
>>>>
>>>> In addition, the similar situations also occur in other drivers such
>>>> as the bnxt_en driver. That can be reproduced easily in kdump kernel
>>>> when SME is active.
>>>>
>>>> Add a check for the deferred attach in the iommu_attach_device() and
>>>> allow to attach the deferred device regardless of how many devices
>>>> are in a group.
>
> Is this iommu_attach_device() call is coming from iommu-dma? (if not, then
> whoever's calling it probably shouldn't be)
>
Yes, you are right, the iommu_attach_device call is coming from iommu-dma.
> Assuming so, then probably what should happen is to move the handling
> currently in iommu_dma_deferred_attach() into the core so that it can call
> __iommu_attach_device() directly - the intent is just to replay that exact
> call skipped in iommu_group_add_device(), so the legacy external
> iommu_attach_device() interface isn't really the right tool for the job
Sounds good. I will check if this can work in various cases. If it's OK, I will
post again.
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index f0305e6aac1b..5e7da902ac36 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -23,7 +23,6 @@
#include <linux/swiotlb.h>
#include <linux/scatterlist.h>
#include <linux/vmalloc.h>
-#include <linux/crash_dump.h>
#include <linux/dma-direct.h>
struct iommu_dma_msi_page {
@@ -378,21 +377,6 @@ static int iommu_dma_init_domain(struct iommu_domain
*domain, dma_addr_t base,
return iova_reserve_iommu_regions(dev, domain);
}
-static int iommu_dma_deferred_attach(struct device *dev,
- struct iommu_domain *domain)
-{
- const struct iommu_ops *ops = domain->ops;
-
- if (!is_kdump_kernel())
- return 0;
-
- if (unlikely(ops->is_attach_deferred &&
- ops->is_attach_deferred(domain, dev)))
- return iommu_attach_device(domain, dev);
-
- return 0;
-}
-
/**
* dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
* page flags.
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ffeebda8d6de..4fed1567b498 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -23,6 +23,7 @@
#include <linux/property.h>
#include <linux/fsl/mc.h>
#include <linux/module.h>
+#include <linux/crash_dump.h>
#include <trace/events/iommu.h>
static struct kset *iommu_group_kset;
@@ -1952,6 +1953,21 @@ static int __iommu_attach_device(struct iommu_domain
*domain,
return ret;
}
+int iommu_dma_deferred_attach(struct device *dev,
+ struct iommu_domain *domain)
+{
+ const struct iommu_ops *ops = domain->ops;
+
+ if (!is_kdump_kernel())
+ return 0;
+
+ if (unlikely(ops->is_attach_deferred &&
+ ops->is_attach_deferred(domain, dev)))
+ return __iommu_attach_device(domain, dev);
+
+ return 0;
+}
+
int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
{
struct iommu_group *group;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index b3f0e2018c62..8e0ee96ca456 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -424,6 +424,8 @@ extern struct iommu_group *iommu_group_get_by_id(int id);
extern void iommu_domain_free(struct iommu_domain *domain);
extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
+extern int iommu_dma_deferred_attach(struct device *dev,
+ struct iommu_domain *domain);
extern void iommu_detach_device(struct iommu_domain *domain,
struct device *dev);
extern int iommu_uapi_cache_invalidate(struct iommu_domain *domain,
@@ -680,6 +682,12 @@ static inline int iommu_attach_device(struct iommu_domain
*domain,
return -ENODEV;
}
+static inline int iommu_dma_deferred_attach(struct device *dev,
+ struct iommu_domain *domain)
+{
+ return -ENODEV;
+}
+
static inline void iommu_detach_device(struct iommu_domain *domain,
struct device *dev)
{
> Alternatively I suppose it *could* just call ops->attach_dev directly, but
> then we miss out on the tracepoint, and deferred attach is arguably one of
> the cases where that's most useful :/
>
Seems good, I could debug it and provide feedback.
Thanks.
Lianbo
> Robin.
>
>>>>
>>>> Signed-off-by: Lianbo Jiang <liji...@redhat.com>
>>>> ---
>>>> drivers/iommu/iommu.c | 5 ++++-
>>>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>>>> index ffeebda8d6de..dccab7b133fb 100644
>>>> --- a/drivers/iommu/iommu.c
>>>> +++ b/drivers/iommu/iommu.c
>>>> @@ -1967,8 +1967,11 @@ int iommu_attach_device(struct iommu_domain
>>>> *domain, struct device *dev)
>>>> */
>>>> mutex_lock(&group->mutex);
>>>> ret = -EINVAL;
>>>> - if (iommu_group_device_count(group) != 1)
>>>> + if (!iommu_is_attach_deferred(domain, dev) &&
>>>> + iommu_group_device_count(group) != 1) {
>>>> + dev_err_ratelimited(dev, "Group has more than one device\n");
>>>> goto out_unlock;
>>>> + }
>>>> ret = __iommu_attach_group(domain, group);
>>>>
>>
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>
