[PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Lu Baolu]

If the default DMA domain of a group doesn't fit a device, it
will still sit in the group but use a private identity domain.
When map/unmap/iova_to_phys come through iommu API, the driver
should still serve them, otherwise, other devices in the same
group will be impacted. Since identity domain has been mapped
with the whole available memory space and RMRRs, we don't need
to worry about the impact on it.

Link: https://www.spinics.net/lists/iommu/msg40416.html
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced with private")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0c8d81f56a30..b73bebea9148 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct iommu_domain *domain,
 	int prot = 0;
 	int ret;
 
-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
-		return -EINVAL;
-
 	if (iommu_prot & IOMMU_READ)
 		prot |= DMA_PTE_READ;
 	if (iommu_prot & IOMMU_WRITE)
@@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
 	/* Cope with horrid API which requires us to unmap more than the
 	   size argument if it happens to be a large-page mapping. */
 	BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
-		return 0;
 
 	if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
 		size = VTD_PAGE_SIZE << level_to_offset_bits(level);
@@ -5556,9 +5551,6 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
 	int level = 0;
 	u64 phys = 0;
 
-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
-		return 0;
-
 	pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
 	if (pte)
 		phys = dma_pte_addr(pte);
-- 
2.17.1

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Jerry Snitselaar]

On Wed Dec 11 19, Lu Baolu wrote:
>If the default DMA domain of a group doesn't fit a device, it
>will still sit in the group but use a private identity domain.
>When map/unmap/iova_to_phys come through iommu API, the driver
>should still serve them, otherwise, other devices in the same
>group will be impacted. Since identity domain has been mapped
>with the whole available memory space and RMRRs, we don't need
>to worry about the impact on it.
>

Does this pose any potential issues with the reverse case where the
group has a default identity domain, and the first device fits that,
but a later device in the group needs dma and gets a private dma
domain?

>Link: https://www.spinics.net/lists/iommu/msg40416.html
>Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced with private")
>Cc: stable@vger.kernel.org # v5.3+
>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>---
> drivers/iommu/intel-iommu.c | 8 --------
> 1 file changed, 8 deletions(-)
>
>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>index 0c8d81f56a30..b73bebea9148 100644
>--- a/drivers/iommu/intel-iommu.c
>+++ b/drivers/iommu/intel-iommu.c
>@@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct iommu_domain *domain,
> 	int prot = 0;
> 	int ret;
>
>-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>-		return -EINVAL;
>-
> 	if (iommu_prot & IOMMU_READ)
> 		prot |= DMA_PTE_READ;
> 	if (iommu_prot & IOMMU_WRITE)
>@@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
> 	/* Cope with horrid API which requires us to unmap more than the
> 	   size argument if it happens to be a large-page mapping. */
> 	BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
>-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>-		return 0;
>
> 	if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
> 		size = VTD_PAGE_SIZE << level_to_offset_bits(level);
>@@ -5556,9 +5551,6 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
> 	int level = 0;
> 	u64 phys = 0;
>
>-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>-		return 0;
>-
> 	pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
> 	if (pte)
> 		phys = dma_pte_addr(pte);
>-- 
>2.17.1
>

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Lu Baolu]

Hi,

On 12/12/19 12:35 AM, Jerry Snitselaar wrote:
> On Wed Dec 11 19, Lu Baolu wrote:
>> If the default DMA domain of a group doesn't fit a device, it
>> will still sit in the group but use a private identity domain.
>> When map/unmap/iova_to_phys come through iommu API, the driver
>> should still serve them, otherwise, other devices in the same
>> group will be impacted. Since identity domain has been mapped
>> with the whole available memory space and RMRRs, we don't need
>> to worry about the impact on it.
>>
> 
> Does this pose any potential issues with the reverse case where the
> group has a default identity domain, and the first device fits that,
> but a later device in the group needs dma and gets a private dma
> domain?

No. iommu_map/unmap() should not be called for default identity domain.

         if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING)))
                 return -EINVAL;

Best regards,
baolu

> 
>> Link: https://www.spinics.net/lists/iommu/msg40416.html
>> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>> Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced 
>> with private")
>> Cc: stable@vger.kernel.org # v5.3+
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> ---
>> drivers/iommu/intel-iommu.c | 8 --------
>> 1 file changed, 8 deletions(-)
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index 0c8d81f56a30..b73bebea9148 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct iommu_domain 
>> *domain,
>>     int prot = 0;
>>     int ret;
>>
>> -    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>> -        return -EINVAL;
>> -
>>     if (iommu_prot & IOMMU_READ)
>>         prot |= DMA_PTE_READ;
>>     if (iommu_prot & IOMMU_WRITE)
>> @@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct 
>> iommu_domain *domain,
>>     /* Cope with horrid API which requires us to unmap more than the
>>        size argument if it happens to be a large-page mapping. */
>>     BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
>> -    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>> -        return 0;
>>
>>     if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
>>         size = VTD_PAGE_SIZE << level_to_offset_bits(level);
>> @@ -5556,9 +5551,6 @@ static phys_addr_t 
>> intel_iommu_iova_to_phys(struct iommu_domain *domain,
>>     int level = 0;
>>     u64 phys = 0;
>>
>> -    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>> -        return 0;
>> -
>>     pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
>>     if (pte)
>>         phys = dma_pte_addr(pte);
>> -- 
>> 2.17.1
>>
> 

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Jerry Snitselaar]

On Wed Dec 11 19, Lu Baolu wrote:
>If the default DMA domain of a group doesn't fit a device, it
>will still sit in the group but use a private identity domain.
>When map/unmap/iova_to_phys come through iommu API, the driver
>should still serve them, otherwise, other devices in the same
>group will be impacted. Since identity domain has been mapped
>with the whole available memory space and RMRRs, we don't need
>to worry about the impact on it.
>
>Link: https://www.spinics.net/lists/iommu/msg40416.html
>Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced with private")
>Cc: stable@vger.kernel.org # v5.3+
>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

>---
> drivers/iommu/intel-iommu.c | 8 --------
> 1 file changed, 8 deletions(-)
>
>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>index 0c8d81f56a30..b73bebea9148 100644
>--- a/drivers/iommu/intel-iommu.c
>+++ b/drivers/iommu/intel-iommu.c
>@@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct iommu_domain *domain,
> 	int prot = 0;
> 	int ret;
>
>-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>-		return -EINVAL;
>-
> 	if (iommu_prot & IOMMU_READ)
> 		prot |= DMA_PTE_READ;
> 	if (iommu_prot & IOMMU_WRITE)
>@@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
> 	/* Cope with horrid API which requires us to unmap more than the
> 	   size argument if it happens to be a large-page mapping. */
> 	BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
>-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>-		return 0;
>
> 	if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
> 		size = VTD_PAGE_SIZE << level_to_offset_bits(level);
>@@ -5556,9 +5551,6 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
> 	int level = 0;
> 	u64 phys = 0;
>
>-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>-		return 0;
>-
> 	pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
> 	if (pte)
> 		phys = dma_pte_addr(pte);
>-- 
>2.17.1
>

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Lu Baolu]

Hi,

On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
> On Wed Dec 11 19, Lu Baolu wrote:
>> If the default DMA domain of a group doesn't fit a device, it
>> will still sit in the group but use a private identity domain.
>> When map/unmap/iova_to_phys come through iommu API, the driver
>> should still serve them, otherwise, other devices in the same
>> group will be impacted. Since identity domain has been mapped
>> with the whole available memory space and RMRRs, we don't need
>> to worry about the impact on it.
>>
>> Link: https://www.spinics.net/lists/iommu/msg40416.html
>> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>> Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced 
>> with private")
>> Cc: stable@vger.kernel.org # v5.3+
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> 
> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

Can you please try this fix and check whether it can fix your problem?
If it helps, do you mind adding a Tested-by?

Best regards,
baolu

> 
>> ---
>> drivers/iommu/intel-iommu.c | 8 --------
>> 1 file changed, 8 deletions(-)
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index 0c8d81f56a30..b73bebea9148 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct iommu_domain 
>> *domain,
>>     int prot = 0;
>>     int ret;
>>
>> -    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>> -        return -EINVAL;
>> -
>>     if (iommu_prot & IOMMU_READ)
>>         prot |= DMA_PTE_READ;
>>     if (iommu_prot & IOMMU_WRITE)
>> @@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct 
>> iommu_domain *domain,
>>     /* Cope with horrid API which requires us to unmap more than the
>>        size argument if it happens to be a large-page mapping. */
>>     BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
>> -    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>> -        return 0;
>>
>>     if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
>>         size = VTD_PAGE_SIZE << level_to_offset_bits(level);
>> @@ -5556,9 +5551,6 @@ static phys_addr_t 
>> intel_iommu_iova_to_phys(struct iommu_domain *domain,
>>     int level = 0;
>>     u64 phys = 0;
>>
>> -    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>> -        return 0;
>> -
>>     pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
>>     if (pte)
>>         phys = dma_pte_addr(pte);
>> -- 
>> 2.17.1
>>
> 

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Jerry Snitselaar]

On Thu Dec 12 19, Lu Baolu wrote:
>Hi,
>
>On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
>>On Wed Dec 11 19, Lu Baolu wrote:
>>>If the default DMA domain of a group doesn't fit a device, it
>>>will still sit in the group but use a private identity domain.
>>>When map/unmap/iova_to_phys come through iommu API, the driver
>>>should still serve them, otherwise, other devices in the same
>>>group will be impacted. Since identity domain has been mapped
>>>with the whole available memory space and RMRRs, we don't need
>>>to worry about the impact on it.
>>>
>>>Link: https://www.spinics.net/lists/iommu/msg40416.html
>>>Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>>>Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains 
>>>replaced with private")
>>>Cc: stable@vger.kernel.org # v5.3+
>>>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>>
>>Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>
>Can you please try this fix and check whether it can fix your problem?
>If it helps, do you mind adding a Tested-by?
>
>Best regards,
>baolu
>

I'm testing with this patch, my patch that moves the direct mapping call,
and Alex's patch for the ISA bridge. It solved the 2 iommu mapping errors
I was seeing with default passthrough, I no longer see all the dmar pte
read access errors, and the system boots allowing me to login. I'm tracking
down 2 issues at the moment. With passthrough I see a problem with 01:00.4
that I mentioned in the earlier email:

[   78.978573] uhci_hcd: USB Universal Host Controller Interface driver
[   78.980842] uhci_hcd 0000:01:00.4: UHCI Host Controller
[   78.982738] uhci_hcd 0000:01:00.4: new USB bus registered, assigned bus number 3
[   78.985222] uhci_hcd 0000:01:00.4: detected 8 ports
[   78.986907] uhci_hcd 0000:01:00.4: port count misdetected? forcing to 2 ports
[   78.989316] uhci_hcd 0000:01:00.4: irq 16, io base 0x00003c00
[   78.994634] uhci_hcd 0000:01:00.4: DMAR: 32bit DMA uses non-identity mapping
[   7 0000:01:00.4: unable to allocate consistent memory for frame list
[   79.499891] uhci_hcd 0000:01:00.4: startup error -16
[   79.501588] uhci_hcd 0000:01:00.4: USB bus 3 deregistered
[   79.503494] uhci_hcd 0000:01:00.4: init 0000:01:00.4 fail, -16
[   79.505497] uhci_hcd: probe of 0000:01:00.4 failed with error -16

If I boot the system with iommu=nopt I see an iommu map failure due to
the prot check in __domain_mapping:

[   40.940589] pci 0000:00:1f.0: iommu_group_add_device: calling iommu_group_create_direct_mappings
[   40.943558] pci 0000:00:1f.0: iommu_group_create_direct_mappings: iterating through mappings
[   40.946402] pci 0000:00:1f.0: iommu_group_create_direct_mappings: calling apply_resv_region
[   40.949184] pci 0000:00:1f.0: iommu_group_create_direct_mappings: entry type is direct
[   40.951819] DMAR: intel_iommu_map: enter
[   40.953128] DMAR: __domain_mapping: prot & (DMA_PTE_READ|DMA_PTE_WRITE) == 0
[   40.955486] DMAR: domain_mapping: __domain_mapping failed
[   40.957348] DMAR: intel_iommu_map: domain_pfn_mapping returned -22
[   40.959466] DMAR: intel_iommu_map: leave
[   40.959468] iommu: iommu_map: ops->map failed iova 0x0 pa 0x0000000000000000 pgsize 0x1000
[   40.963511] pci 0000:00:1f.0: iommu_group_create_direct_mappings: iommu_map failed
[   40.966026] pci 0000:00:1f.0: iommu_group_create_direct_mappings: leaving func
[   40.968487] pci 0000:00:1f.0: iommu_group_add_device: calling __iommu_attach_device
[   40.971016] pci 0000:00:1f.0: Adding to iommu group 19
[   40.972731] pci 0000:00:1f.0: DMAR: domain->type is dma

/sys/kernel/iommu_groups/19
[root@hp-dl388g8-07 19]# cat reserved_regions 
0x0000000000000000 0x0000000000ffffff direct
0x00000000bdf6e000 0x00000000bdf84fff direct
0x00000000fee00000 0x00000000feefffff msi

00:1f.0 ISA bridge: Intel Corporation C600/X79 series chipset LPC Controller

>>
>>>---
>>>drivers/iommu/intel-iommu.c | 8 --------
>>>1 file changed, 8 deletions(-)
>>>
>>>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>>>index 0c8d81f56a30..b73bebea9148 100644
>>>--- a/drivers/iommu/intel-iommu.c
>>>+++ b/drivers/iommu/intel-iommu.c
>>>@@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct 
>>>iommu_domain *domain,
>>>    int prot = 0;
>>>    int ret;
>>>
>>>-    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>>>-        return -EINVAL;
>>>-
>>>    if (iommu_prot & IOMMU_READ)
>>>        prot |= DMA_PTE_READ;
>>>    if (iommu_prot & IOMMU_WRITE)
>>>@@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct 
>>>iommu_domain *domain,
>>>    /* Cope with horrid API which requires us to unmap more than the
>>>       size argument if it happens to be a large-page mapping. */
>>>    BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
>>>-    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>>>-        return 0;
>>>
>>>    if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
>>>        size = VTD_PAGE_SIZE << level_to_offset_bits(level);
>>>@@ -5556,9 +5551,6 @@ static phys_addr_t 
>>>intel_iommu_iova_to_phys(struct iommu_domain *domain,
>>>    int level = 0;
>>>    u64 phys = 0;
>>>
>>>-    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>>>-        return 0;
>>>-
>>>    pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
>>>    if (pte)
>>>        phys = dma_pte_addr(pte);
>>>-- 
>>>2.17.1
>>>
>>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Lu Baolu]

Hi,

On 12/13/19 8:30 AM, Jerry Snitselaar wrote:
> On Thu Dec 12 19, Lu Baolu wrote:
>> Hi,
>>
>> On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
>>> On Wed Dec 11 19, Lu Baolu wrote:
>>>> If the default DMA domain of a group doesn't fit a device, it
>>>> will still sit in the group but use a private identity domain.
>>>> When map/unmap/iova_to_phys come through iommu API, the driver
>>>> should still serve them, otherwise, other devices in the same
>>>> group will be impacted. Since identity domain has been mapped
>>>> with the whole available memory space and RMRRs, we don't need
>>>> to worry about the impact on it.
>>>>
>>>> Link: https://www.spinics.net/lists/iommu/msg40416.html
>>>> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>>>> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>> Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced 
>>>> with private")
>>>> Cc: stable@vger.kernel.org # v5.3+
>>>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>>>
>>> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>
>> Can you please try this fix and check whether it can fix your problem?
>> If it helps, do you mind adding a Tested-by?
>>
>> Best regards,
>> baolu
>>
> 
> I'm testing with this patch, my patch that moves the direct mapping call,
> and Alex's patch for the ISA bridge. It solved the 2 iommu mapping errors
> I was seeing with default passthrough, I no longer see all the dmar pte
> read access errors, and the system boots allowing me to login. I'm tracking
> down 2 issues at the moment. With passthrough I see a problem with 01:00.4
> that I mentioned in the earlier email:
> 
> [   78.978573] uhci_hcd: USB Universal Host Controller Interface driver
> [   78.980842] uhci_hcd 0000:01:00.4: UHCI Host Controller
> [   78.982738] uhci_hcd 0000:01:00.4: new USB bus registered, assigned 
> bus number 3
> [   78.985222] uhci_hcd 0000:01:00.4: detected 8 ports
> [   78.986907] uhci_hcd 0000:01:00.4: port count misdetected? forcing to 
> 2 ports
> [   78.989316] uhci_hcd 0000:01:00.4: irq 16, io base 0x00003c00
> [   78.994634] uhci_hcd 0000:01:00.4: DMAR: 32bit DMA uses non-identity 
> mapping
> [   7 0000:01:00.4: unable to allocate consistent memory for frame list
> [   79.499891] uhci_hcd 0000:01:00.4: startup error -16
> [   79.501588] uhci_hcd 0000:01:00.4: USB bus 3 deregistered
> [   79.503494] uhci_hcd 0000:01:00.4: init 0000:01:00.4 fail, -16
> [   79.505497] uhci_hcd: probe of 0000:01:00.4 failed with error -16
> 
> If I boot the system with iommu=nopt I see an iommu map failure due to
> the prot check in __domain_mapping:
> 
> [   40.940589] pci 0000:00:1f.0: iommu_group_add_device: calling 
> iommu_group_create_direct_mappings
> [   40.943558] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
> iterating through mappings
> [   40.946402] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
> calling apply_resv_region
> [   40.949184] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
> entry type is direct
> [   40.951819] DMAR: intel_iommu_map: enter
> [   40.953128] DMAR: __domain_mapping: prot & 
> (DMA_PTE_READ|DMA_PTE_WRITE) == 0
> [   40.955486] DMAR: domain_mapping: __domain_mapping failed
> [   40.957348] DMAR: intel_iommu_map: domain_pfn_mapping returned -22
> [   40.959466] DMAR: intel_iommu_map: leave
> [   40.959468] iommu: iommu_map: ops->map failed iova 0x0 pa 
> 0x0000000000000000 pgsize 0x1000
> [   40.963511] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
> iommu_map failed
> [   40.966026] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
> leaving func
> [   40.968487] pci 0000:00:1f.0: iommu_group_add_device: calling 
> __iommu_attach_device
> [   40.971016] pci 0000:00:1f.0: Adding to iommu group 19
> [   40.972731] pci 0000:00:1f.0: DMAR: domain->type is dma
> 
> /sys/kernel/iommu_groups/19
> [root@hp-dl388g8-07 19]# cat reserved_regions 0x0000000000000000 
> 0x0000000000ffffff direct
> 0x00000000bdf6e000 0x00000000bdf84fff direct
> 0x00000000fee00000 0x00000000feefffff msi
> 
> 00:1f.0 ISA bridge: Intel Corporation C600/X79 series chipset LPC 
> Controller

This seems to be another issue?

Best regards,
baolu

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Jerry Snitselaar]

On Fri Dec 13 19, Lu Baolu wrote:
>Hi,
>
>On 12/13/19 8:30 AM, Jerry Snitselaar wrote:
>>On Thu Dec 12 19, Lu Baolu wrote:
>>>Hi,
>>>
>>>On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
>>>>On Wed Dec 11 19, Lu Baolu wrote:
>>>>>If the default DMA domain of a group doesn't fit a device, it
>>>>>will still sit in the group but use a private identity domain.
>>>>>When map/unmap/iova_to_phys come through iommu API, the driver
>>>>>should still serve them, otherwise, other devices in the same
>>>>>group will be impacted. Since identity domain has been mapped
>>>>>with the whole available memory space and RMRRs, we don't need
>>>>>to worry about the impact on it.
>>>>>
>>>>>Link: https://www.spinics.net/lists/iommu/msg40416.html
>>>>>Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains 
>>>>>replaced with private")
>>>>>Cc: stable@vger.kernel.org # v5.3+
>>>>>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>>>>
>>>>Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>
>>>Can you please try this fix and check whether it can fix your problem?
>>>If it helps, do you mind adding a Tested-by?
>>>
>>>Best regards,
>>>baolu
>>>
>>
>>I'm testing with this patch, my patch that moves the direct mapping call,
>>and Alex's patch for the ISA bridge. It solved the 2 iommu mapping errors
>>I was seeing with default passthrough, I no longer see all the dmar pte
>>read access errors, and the system boots allowing me to login. I'm tracking
>>down 2 issues at the moment. With passthrough I see a problem with 01:00.4
>>that I mentioned in the earlier email:
>>
>>[   78.978573] uhci_hcd: USB Universal Host Controller Interface driver
>>[   78.980842] uhci_hcd 0000:01:00.4: UHCI Host Controller
>>[   78.982738] uhci_hcd 0000:01:00.4: new USB bus registered, 
>>assigned bus number 3
>>[   78.985222] uhci_hcd 0000:01:00.4: detected 8 ports
>>[   78.986907] uhci_hcd 0000:01:00.4: port count misdetected? 
>>forcing to 2 ports
>>[   78.989316] uhci_hcd 0000:01:00.4: irq 16, io base 0x00003c00
>>[   78.994634] uhci_hcd 0000:01:00.4: DMAR: 32bit DMA uses 
>>non-identity mapping
>>[   7 0000:01:00.4: unable to allocate consistent memory for frame list
>>[   79.499891] uhci_hcd 0000:01:00.4: startup error -16
>>[   79.501588] uhci_hcd 0000:01:00.4: USB bus 3 deregistered
>>[   79.503494] uhci_hcd 0000:01:00.4: init 0000:01:00.4 fail, -16
>>[   79.505497] uhci_hcd: probe of 0000:01:00.4 failed with error -16
>>
>>If I boot the system with iommu=nopt I see an iommu map failure due to
>>the prot check in __domain_mapping:
>>
>>[   40.940589] pci 0000:00:1f.0: iommu_group_add_device: calling 
>>iommu_group_create_direct_mappings
>>[   40.943558] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>iterating through mappings
>>[   40.946402] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>calling apply_resv_region
>>[   40.949184] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>entry type is direct
>>[   40.951819] DMAR: intel_iommu_map: enter
>>[   40.953128] DMAR: __domain_mapping: prot & 
>>(DMA_PTE_READ|DMA_PTE_WRITE) == 0
>>[   40.955486] DMAR: domain_mapping: __domain_mapping failed
>>[   40.957348] DMAR: intel_iommu_map: domain_pfn_mapping returned -22
>>[   40.959466] DMAR: intel_iommu_map: leave
>>[   40.959468] iommu: iommu_map: ops->map failed iova 0x0 pa 
>>0x0000000000000000 pgsize 0x1000
>>[   40.963511] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>iommu_map failed
>>[   40.966026] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>leaving func
>>[   40.968487] pci 0000:00:1f.0: iommu_group_add_device: calling 
>>__iommu_attach_device
>>[   40.971016] pci 0000:00:1f.0: Adding to iommu group 19
>>[   40.972731] pci 0000:00:1f.0: DMAR: domain->type is dma
>>
>>/sys/kernel/iommu_groups/19
>>[root@hp-dl388g8-07 19]# cat reserved_regions 0x0000000000000000 
>>0x0000000000ffffff direct
>>0x00000000bdf6e000 0x00000000bdf84fff direct
>>0x00000000fee00000 0x00000000feefffff msi
>>
>>00:1f.0 ISA bridge: Intel Corporation C600/X79 series chipset LPC 
>>Controller
>
>This seems to be another issue?
>
>Best regards,
>baolu

In intel_iommu_get_resv_regions this iommu_alloc_resv_region is called
with prot set to 0:

                 if ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA) {
                         reg = iommu_alloc_resv_region(0, 1UL << 24, 0,
                                                       IOMMU_RESV_DIRECT_RELAXABLE);
                         if (reg)

I wonder if this is an issue with the region starting at 0x0 and this
bit in iommu_group_create_mappings:

			phys_addr = iommu_iova_to_phys(domain, addr);
			if (phys_addr)
				continue;

Off to stick in some more debugging statements.

Regards,
Jerry

>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Jerry Snitselaar]

On Thu Dec 12 19, Jerry Snitselaar wrote:
>On Fri Dec 13 19, Lu Baolu wrote:
>>Hi,
>>
>>On 12/13/19 8:30 AM, Jerry Snitselaar wrote:
>>>On Thu Dec 12 19, Lu Baolu wrote:
>>>>Hi,
>>>>
>>>>On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
>>>>>On Wed Dec 11 19, Lu Baolu wrote:
>>>>>>If the default DMA domain of a group doesn't fit a device, it
>>>>>>will still sit in the group but use a private identity domain.
>>>>>>When map/unmap/iova_to_phys come through iommu API, the driver
>>>>>>should still serve them, otherwise, other devices in the same
>>>>>>group will be impacted. Since identity domain has been mapped
>>>>>>with the whole available memory space and RMRRs, we don't need
>>>>>>to worry about the impact on it.
>>>>>>
>>>>>>Link: https://www.spinics.net/lists/iommu/msg40416.html
>>>>>>Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>>Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>>Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains 
>>>>>>replaced with private")
>>>>>>Cc: stable@vger.kernel.org # v5.3+
>>>>>>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>>>>>
>>>>>Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>
>>>>Can you please try this fix and check whether it can fix your problem?
>>>>If it helps, do you mind adding a Tested-by?
>>>>
>>>>Best regards,
>>>>baolu
>>>>
>>>
>>>I'm testing with this patch, my patch that moves the direct mapping call,
>>>and Alex's patch for the ISA bridge. It solved the 2 iommu mapping errors
>>>I was seeing with default passthrough, I no longer see all the dmar pte
>>>read access errors, and the system boots allowing me to login. I'm tracking
>>>down 2 issues at the moment. With passthrough I see a problem with 01:00.4
>>>that I mentioned in the earlier email:
>>>
>>>[   78.978573] uhci_hcd: USB Universal Host Controller Interface driver
>>>[   78.980842] uhci_hcd 0000:01:00.4: UHCI Host Controller
>>>[   78.982738] uhci_hcd 0000:01:00.4: new USB bus registered, 
>>>assigned bus number 3
>>>[   78.985222] uhci_hcd 0000:01:00.4: detected 8 ports
>>>[   78.986907] uhci_hcd 0000:01:00.4: port count misdetected? 
>>>forcing to 2 ports
>>>[   78.989316] uhci_hcd 0000:01:00.4: irq 16, io base 0x00003c00
>>>[   78.994634] uhci_hcd 0000:01:00.4: DMAR: 32bit DMA uses 
>>>non-identity mapping
>>>[   7 0000:01:00.4: unable to allocate consistent memory for frame list
>>>[   79.499891] uhci_hcd 0000:01:00.4: startup error -16
>>>[   79.501588] uhci_hcd 0000:01:00.4: USB bus 3 deregistered
>>>[   79.503494] uhci_hcd 0000:01:00.4: init 0000:01:00.4 fail, -16
>>>[   79.505497] uhci_hcd: probe of 0000:01:00.4 failed with error -16
>>>
>>>If I boot the system with iommu=nopt I see an iommu map failure due to
>>>the prot check in __domain_mapping:
>>>
>>>[   40.940589] pci 0000:00:1f.0: iommu_group_add_device: calling 
>>>iommu_group_create_direct_mappings
>>>[   40.943558] pci 0000:00:1f.0: 
>>>iommu_group_create_direct_mappings: iterating through mappings
>>>[   40.946402] pci 0000:00:1f.0: 
>>>iommu_group_create_direct_mappings: calling apply_resv_region
>>>[   40.949184] pci 0000:00:1f.0: 
>>>iommu_group_create_direct_mappings: entry type is direct
>>>[   40.951819] DMAR: intel_iommu_map: enter
>>>[   40.953128] DMAR: __domain_mapping: prot & 
>>>(DMA_PTE_READ|DMA_PTE_WRITE) == 0
>>>[   40.955486] DMAR: domain_mapping: __domain_mapping failed
>>>[   40.957348] DMAR: intel_iommu_map: domain_pfn_mapping returned -22
>>>[   40.959466] DMAR: intel_iommu_map: leave
>>>[   40.959468] iommu: iommu_map: ops->map failed iova 0x0 pa 
>>>0x0000000000000000 pgsize 0x1000
>>>[   40.963511] pci 0000:00:1f.0: 
>>>iommu_group_create_direct_mappings: iommu_map failed
>>>[   40.966026] pci 0000:00:1f.0: 
>>>iommu_group_create_direct_mappings: leaving func
>>>[   40.968487] pci 0000:00:1f.0: iommu_group_add_device: calling 
>>>__iommu_attach_device
>>>[   40.971016] pci 0000:00:1f.0: Adding to iommu group 19
>>>[   40.972731] pci 0000:00:1f.0: DMAR: domain->type is dma
>>>
>>>/sys/kernel/iommu_groups/19
>>>[root@hp-dl388g8-07 19]# cat reserved_regions 0x0000000000000000 
>>>0x0000000000ffffff direct
>>>0x00000000bdf6e000 0x00000000bdf84fff direct
>>>0x00000000fee00000 0x00000000feefffff msi
>>>
>>>00:1f.0 ISA bridge: Intel Corporation C600/X79 series chipset LPC 
>>>Controller
>>
>>This seems to be another issue?
>>
>>Best regards,
>>baolu
>
>In intel_iommu_get_resv_regions this iommu_alloc_resv_region is called
>with prot set to 0:
>
>                if ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA) {
>                        reg = iommu_alloc_resv_region(0, 1UL << 24, 0,
>                                                      IOMMU_RESV_DIRECT_RELAXABLE);
>                        if (reg)
>

Looking at the older code for the ISA bridge it looks like it called
iommu_prepare_identity_map -> domain_prepare_identity_map ->
iommu_domain_identity_map -> and finally __domain_mapping with DMA_PTE_READ|DMA_PTE_WRITE?

>I wonder if this is an issue with the region starting at 0x0 and this
>bit in iommu_group_create_mappings:
>
>			phys_addr = iommu_iova_to_phys(domain, addr);
>			if (phys_addr)
>				continue;

Disregard this

>
>Off to stick in some more debugging statements.
>
>Regards,
>Jerry
>
>>_______________________________________________
>>iommu mailing list
>>iommu@lists.linux-foundation.org
>>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Lu Baolu]

Hi,

On 12/13/19 11:16 AM, Jerry Snitselaar wrote:
> On Thu Dec 12 19, Jerry Snitselaar wrote:
>> On Fri Dec 13 19, Lu Baolu wrote:
>>> Hi,
>>>
>>> On 12/13/19 8:30 AM, Jerry Snitselaar wrote:
>>>> On Thu Dec 12 19, Lu Baolu wrote:
>>>>> Hi,
>>>>>
>>>>> On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
>>>>>> On Wed Dec 11 19, Lu Baolu wrote:
>>>>>>> If the default DMA domain of a group doesn't fit a device, it
>>>>>>> will still sit in the group but use a private identity domain.
>>>>>>> When map/unmap/iova_to_phys come through iommu API, the driver
>>>>>>> should still serve them, otherwise, other devices in the same
>>>>>>> group will be impacted. Since identity domain has been mapped
>>>>>>> with the whole available memory space and RMRRs, we don't need
>>>>>>> to worry about the impact on it.
>>>>>>>
>>>>>>> Link: https://www.spinics.net/lists/iommu/msg40416.html
>>>>>>> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>>> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>>> Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains 
>>>>>>> replaced with private")
>>>>>>> Cc: stable@vger.kernel.org # v5.3+
>>>>>>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>>>>>>
>>>>>> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>>>
>>>>> Can you please try this fix and check whether it can fix your problem?
>>>>> If it helps, do you mind adding a Tested-by?
>>>>>
>>>>> Best regards,
>>>>> baolu
>>>>>
>>>>
>>>> I'm testing with this patch, my patch that moves the direct mapping 
>>>> call,
>>>> and Alex's patch for the ISA bridge. It solved the 2 iommu mapping 
>>>> errors
>>>> I was seeing with default passthrough, I no longer see all the dmar pte
>>>> read access errors, and the system boots allowing me to login. I'm 
>>>> tracking
>>>> down 2 issues at the moment. With passthrough I see a problem with 
>>>> 01:00.4
>>>> that I mentioned in the earlier email:
>>>>
>>>> [   78.978573] uhci_hcd: USB Universal Host Controller Interface driver
>>>> [   78.980842] uhci_hcd 0000:01:00.4: UHCI Host Controller
>>>> [   78.982738] uhci_hcd 0000:01:00.4: new USB bus registered, 
>>>> assigned bus number 3
>>>> [   78.985222] uhci_hcd 0000:01:00.4: detected 8 ports
>>>> [   78.986907] uhci_hcd 0000:01:00.4: port count misdetected? 
>>>> forcing to 2 ports
>>>> [   78.989316] uhci_hcd 0000:01:00.4: irq 16, io base 0x00003c00
>>>> [   78.994634] uhci_hcd 0000:01:00.4: DMAR: 32bit DMA uses 
>>>> non-identity mapping
>>>> [   7 0000:01:00.4: unable to allocate consistent memory for frame list
>>>> [   79.499891] uhci_hcd 0000:01:00.4: startup error -16
>>>> [   79.501588] uhci_hcd 0000:01:00.4: USB bus 3 deregistered
>>>> [   79.503494] uhci_hcd 0000:01:00.4: init 0000:01:00.4 fail, -16
>>>> [   79.505497] uhci_hcd: probe of 0000:01:00.4 failed with error -16
>>>>
>>>> If I boot the system with iommu=nopt I see an iommu map failure due to
>>>> the prot check in __domain_mapping:
>>>>
>>>> [   40.940589] pci 0000:00:1f.0: iommu_group_add_device: calling 
>>>> iommu_group_create_direct_mappings
>>>> [   40.943558] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>>> iterating through mappings
>>>> [   40.946402] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>>> calling apply_resv_region
>>>> [   40.949184] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>>> entry type is direct
>>>> [   40.951819] DMAR: intel_iommu_map: enter
>>>> [   40.953128] DMAR: __domain_mapping: prot & 
>>>> (DMA_PTE_READ|DMA_PTE_WRITE) == 0
>>>> [   40.955486] DMAR: domain_mapping: __domain_mapping failed
>>>> [   40.957348] DMAR: intel_iommu_map: domain_pfn_mapping returned -22
>>>> [   40.959466] DMAR: intel_iommu_map: leave
>>>> [   40.959468] iommu: iommu_map: ops->map failed iova 0x0 pa 
>>>> 0x0000000000000000 pgsize 0x1000
>>>> [   40.963511] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>>> iommu_map failed
>>>> [   40.966026] pci 0000:00:1f.0: iommu_group_create_direct_mappings: 
>>>> leaving func
>>>> [   40.968487] pci 0000:00:1f.0: iommu_group_add_device: calling 
>>>> __iommu_attach_device
>>>> [   40.971016] pci 0000:00:1f.0: Adding to iommu group 19
>>>> [   40.972731] pci 0000:00:1f.0: DMAR: domain->type is dma
>>>>
>>>> /sys/kernel/iommu_groups/19
>>>> [root@hp-dl388g8-07 19]# cat reserved_regions 0x0000000000000000 
>>>> 0x0000000000ffffff direct
>>>> 0x00000000bdf6e000 0x00000000bdf84fff direct
>>>> 0x00000000fee00000 0x00000000feefffff msi
>>>>
>>>> 00:1f.0 ISA bridge: Intel Corporation C600/X79 series chipset LPC 
>>>> Controller
>>>
>>> This seems to be another issue?
>>>
>>> Best regards,
>>> baolu
>>
>> In intel_iommu_get_resv_regions this iommu_alloc_resv_region is called
>> with prot set to 0:
>>
>>                if ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA) {
>>                        reg = iommu_alloc_resv_region(0, 1UL << 24, 0,
>>                                                      
>> IOMMU_RESV_DIRECT_RELAXABLE);
>>                        if (reg)
>>
> 
> Looking at the older code for the ISA bridge it looks like it called
> iommu_prepare_identity_map -> domain_prepare_identity_map ->
> iommu_domain_identity_map -> and finally __domain_mapping with 
> DMA_PTE_READ|DMA_PTE_WRITE?

Yes. Returning a reserved region without any access permission makes no
sense. Can you please post a fix for this?

Best regards,
baolu

Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Jerry Snitselaar]

On Thu Dec 12 19, Lu Baolu wrote:
>Hi,
>
>On 12/12/19 9:49 AM, Jerry Snitselaar wrote:
>>On Wed Dec 11 19, Lu Baolu wrote:
>>>If the default DMA domain of a group doesn't fit a device, it
>>>will still sit in the group but use a private identity domain.
>>>When map/unmap/iova_to_phys come through iommu API, the driver
>>>should still serve them, otherwise, other devices in the same
>>>group will be impacted. Since identity domain has been mapped
>>>with the whole available memory space and RMRRs, we don't need
>>>to worry about the impact on it.
>>>
>>>Link: https://www.spinics.net/lists/iommu/msg40416.html
>>>Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>>>Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>>Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains 
>>>replaced with private")
>>>Cc: stable@vger.kernel.org # v5.3+
>>>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>>
>>Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
>
>Can you please try this fix and check whether it can fix your problem?
>If it helps, do you mind adding a Tested-by?
>
>Best regards,
>baolu
>

Tested-by: Jerry Snitselaar <jsnitsel@redhat.com>

>>
>>>---
>>>drivers/iommu/intel-iommu.c | 8 --------
>>>1 file changed, 8 deletions(-)
>>>
>>>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>>>index 0c8d81f56a30..b73bebea9148 100644
>>>--- a/drivers/iommu/intel-iommu.c
>>>+++ b/drivers/iommu/intel-iommu.c
>>>@@ -5478,9 +5478,6 @@ static int intel_iommu_map(struct 
>>>iommu_domain *domain,
>>>    int prot = 0;
>>>    int ret;
>>>
>>>-    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>>>-        return -EINVAL;
>>>-
>>>    if (iommu_prot & IOMMU_READ)
>>>        prot |= DMA_PTE_READ;
>>>    if (iommu_prot & IOMMU_WRITE)
>>>@@ -5523,8 +5520,6 @@ static size_t intel_iommu_unmap(struct 
>>>iommu_domain *domain,
>>>    /* Cope with horrid API which requires us to unmap more than the
>>>       size argument if it happens to be a large-page mapping. */
>>>    BUG_ON(!pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level));
>>>-    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>>>-        return 0;
>>>
>>>    if (size < VTD_PAGE_SIZE << level_to_offset_bits(level))
>>>        size = VTD_PAGE_SIZE << level_to_offset_bits(level);
>>>@@ -5556,9 +5551,6 @@ static phys_addr_t 
>>>intel_iommu_iova_to_phys(struct iommu_domain *domain,
>>>    int level = 0;
>>>    u64 phys = 0;
>>>
>>>-    if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
>>>-        return 0;
>>>-
>>>    pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
>>>    if (pte)
>>>        phys = dma_pte_addr(pte);
>>>-- 
>>>2.17.1
>>>
>>
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Re: [PATCH 1/1] iommu/vt-d: Fix dmar pte read access not set error

[Joerg Roedel]

On Wed, Dec 11, 2019 at 09:40:15AM +0800, Lu Baolu wrote:
> If the default DMA domain of a group doesn't fit a device, it
> will still sit in the group but use a private identity domain.
> When map/unmap/iova_to_phys come through iommu API, the driver
> should still serve them, otherwise, other devices in the same
> group will be impacted. Since identity domain has been mapped
> with the whole available memory space and RMRRs, we don't need
> to worry about the impact on it.
> 
> Link: https://www.spinics.net/lists/iommu/msg40416.html
> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
> Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Fixes: 942067f1b6b97 ("iommu/vt-d: Identify default domains replaced with private")
> Cc: stable@vger.kernel.org # v5.3+
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/intel-iommu.c | 8 --------
>  1 file changed, 8 deletions(-)

Applied for v5.5, thanks.