Re: [PATCH v8 04/10] iommu/vt-d: Support flushing more translation cache types

Lu Baolu
2020-01-10T01:18:49Z

Hi,

On 1/10/20 5:50 AM, Jacob Pan wrote:
> On Thu, 19 Dec 2019 10:46:51 +0800
> Lu Baolu<baolu.lu@linux.intel.com> wrote:
>
>> Hi,
>>
>> On 12/17/19 3:24 AM, Jacob Pan wrote:
>>> When Shared Virtual Memory is exposed to a guest via vIOMMU,
>>> scalable IOTLB invalidation may be passed down from outside IOMMU
>>> subsystems. This patch adds invalidation functions that can be used
>>> for additional translation cache types.
>>>
>>> Signed-off-by: Jacob Pan<jacob.jun.pan@linux.intel.com>
>>> ---
>>> drivers/iommu/dmar.c | 46
>>> +++++++++++++++++++++++++++++++++++++++++++++
>>> drivers/iommu/intel-pasid.c | 3 ++- include/linux/intel-iommu.h |
>>> 21 +++++++++++++++++---- 3 files changed, 65 insertions(+), 5
>>> deletions(-)
>>>
>>> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
>>> index 3acfa6a25fa2..f2f5d75da94a 100644
>>> --- a/drivers/iommu/dmar.c
>>> +++ b/drivers/iommu/dmar.c
>>> @@ -1348,6 +1348,20 @@ void qi_flush_iotlb(struct intel_iommu
>>> *iommu, u16 did, u64 addr, qi_submit_sync(&desc, iommu);
>>> }
>>>
>>> +/* PASID-based IOTLB Invalidate */
>>> +void qi_flush_iotlb_pasid(struct intel_iommu *iommu, u16 did, u64
>>> addr, u32 pasid,
>>> + unsigned int size_order, u64 granu, int ih)
>>> +{
>>> + struct qi_desc desc = {.qw2 = 0, .qw3 = 0};
>>> +
>>> + desc.qw0 = QI_EIOTLB_PASID(pasid) | QI_EIOTLB_DID(did) |
>>> + QI_EIOTLB_GRAN(granu) | QI_EIOTLB_TYPE;
>>> + desc.qw1 = QI_EIOTLB_ADDR(addr) | QI_EIOTLB_IH(ih) |
>>> + QI_EIOTLB_AM(size_order);
>>> +
>>> + qi_submit_sync(&desc, iommu);
>>> +}
>> There's another version of pasid-based iotlb invalidation.
>>
>> https://lkml.org/lkml/2019/12/10/2128
>>
>> Let's consider merging them.
>>
> Absolutely, the difference i see is that the granularity is explicit
> here. Here we do invalidation request from the guest. Perhaps, we can
> look at consolidation once this use case is supported?
>

Looks good to me. :-)

Best regards,
baolu