linux-kernel - Re: [PATCH] habanalabs: Stop using iommu

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Message-ID: <97c6b2e1-3d9f-bf03-a14e-df3249d166dd@arm.com>
Date:   Mon, 11 Apr 2022 11:43:24 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Oded Gabbay <ogabbay@...nel.org>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>,
        "list@....net:IOMMU DRIVERS" <iommu@...ts.linux-foundation.org>,
        Joerg Roedel <joro@...tes.org>,
        iommu@...ts.linux-foundation.org
Subject: Re: [PATCH] habanalabs: Stop using iommu_present()

On 2022-04-10 11:59, Oded Gabbay wrote:
> On Tue, Apr 5, 2022 at 4:46 PM Robin Murphy <robin.murphy@....com> wrote:
>>
>> Even if an IOMMU might be present for some PCI segment in the system,
>> that doesn't necessarily mean it provides translation for the device
>> we care about. Replace iommu_present() with a more appropriate check.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@....com>
>> ---
>>   drivers/misc/habanalabs/gaudi/gaudi.c | 8 ++++----
>>   drivers/misc/habanalabs/goya/goya.c   | 8 ++++----
>>   2 files changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/misc/habanalabs/gaudi/gaudi.c b/drivers/misc/habanalabs/gaudi/gaudi.c
>> index 21c2b678ff72..5dc66dc7618e 100644
>> --- a/drivers/misc/habanalabs/gaudi/gaudi.c
>> +++ b/drivers/misc/habanalabs/gaudi/gaudi.c
>> @@ -6133,7 +6133,7 @@ static int gaudi_debugfs_read32(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>
>>                  *val = *(u32 *) phys_to_virt(addr - HOST_PHYS_BASE);
>>
>> @@ -6176,7 +6176,7 @@ static int gaudi_debugfs_write32(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>
>>                  *(u32 *) phys_to_virt(addr - HOST_PHYS_BASE) = val;
>>
>> @@ -6223,7 +6223,7 @@ static int gaudi_debugfs_read64(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>
>>                  *val = *(u64 *) phys_to_virt(addr - HOST_PHYS_BASE);
>>
>> @@ -6268,7 +6268,7 @@ static int gaudi_debugfs_write64(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>
>>                  *(u64 *) phys_to_virt(addr - HOST_PHYS_BASE) = val;
>>
>> diff --git a/drivers/misc/habanalabs/goya/goya.c b/drivers/misc/habanalabs/goya/goya.c
>> index ec9358bcbf0b..0c455bf460f4 100644
>> --- a/drivers/misc/habanalabs/goya/goya.c
>> +++ b/drivers/misc/habanalabs/goya/goya.c
>> @@ -4309,7 +4309,7 @@ static int goya_debugfs_read32(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>                  *val = *(u32 *) phys_to_virt(addr - HOST_PHYS_BASE);
>>
>>          } else {
>> @@ -4369,7 +4369,7 @@ static int goya_debugfs_write32(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>                  *(u32 *) phys_to_virt(addr - HOST_PHYS_BASE) = val;
>>
>>          } else {
>> @@ -4418,7 +4418,7 @@ static int goya_debugfs_read64(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>                  *val = *(u64 *) phys_to_virt(addr - HOST_PHYS_BASE);
>>
>>          } else {
>> @@ -4465,7 +4465,7 @@ static int goya_debugfs_write64(struct hl_device *hdev, u64 addr,
>>                          rc = -EIO;
>>
>>          } else if (addr >= HOST_PHYS_BASE && addr < host_phys_end &&
>> -                       user_address && !iommu_present(&pci_bus_type)) {
>> +                       user_address && !device_iommu_mapped(&hdev->pdev->dev)) {
>>                  *(u64 *) phys_to_virt(addr - HOST_PHYS_BASE) = val;
>>
>>          } else {
>> --
>> 2.28.0.dirty
>>
> 
> Hi Robin,
> Can you please rebase this over the latest habanalabs-next ?
> The code was totally changed, but I think your core change is
> definitely relevant.

Oh, lovely, that makes for a much nicer patch indeed! I'll spin a v2 
shortly.

Thanks,
Robin.