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Re: [Qemu-ppc] [RFC PATCH qemu 1/3] memory: Add get_fd() hook for IOMMU
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-ppc] [RFC PATCH qemu 1/3] memory: Add get_fd() hook for IOMMU MR |
Date: |
Wed, 29 Mar 2017 16:08:52 +1100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 |
On 29/03/17 14:35, David Gibson wrote:
> On Tue, Mar 28, 2017 at 11:48:29AM -0600, Alex Williamson wrote:
>> On Tue, 28 Mar 2017 20:05:28 +1100
>> Alexey Kardashevskiy <address@hidden> wrote:
>>
>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>> ---
>>> include/exec/memory.h | 2 ++
>>> hw/ppc/spapr_iommu.c | 8 ++++++++
>>> 2 files changed, 10 insertions(+)
>>>
>>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>>> index e39256ad03..925c10b35b 100644
>>> --- a/include/exec/memory.h
>>> +++ b/include/exec/memory.h
>>> @@ -174,6 +174,8 @@ struct MemoryRegionIOMMUOps {
>>> void (*notify_flag_changed)(MemoryRegion *iommu,
>>> IOMMUNotifierFlag old_flags,
>>> IOMMUNotifierFlag new_flags);
>>> + /* Returns a kernel fd for IOMMU */
>>> + int (*get_fd)(MemoryRegion *iommu);
>>
>> What if we used this as a prototype:
>>
>> int (*get_fd)(IOMMUFdType type, MemoryRegion *iommu);
>>
>> And then we defined:
>>
>> typedef enum {
>> SPAPR_IOMMU_TABLE_FD = 0,
>> } IOMMUFdType;
>
> Are we expecting any new types of fd? Maybe it would be simpler just
> to name this spapr_tce_fd() or something more specific, and only
> generalize if we really need it for another fd type.
So far we managed to keep VFIO and sPAPR-IOMMU relatively separate - they
do not include each others headers and interact via memory regions and
kernel uapi interface. The only direct connection between VFIO and sPAPR at
all is vfio_eeh_as_ok/vfio_eeh_as_op which is rather workaround. I like
this separation tbh.
>
>>
>> Such that you're actually asking the IOMMUOps for a specific type of FD
>> and it either has it or not, so the caller doesn't need to assume what
>> it is they get back.
>>
>> Furthermore, add:
>>
>> int memory_region_iommu_get_fd(IOMMUFdType type, MemoryRegion *mr)
>> {
>> assert(memory_region_is_iommu(mr));
>>
>> if (mr->iommu_ops && mr->iommu_ops->get_fd) {
>> return mr->iommu_ops->get_fd(type, mr);
>> }
>>
>> return -1;
>> }
>>
>>> };
>>>
>>
>> This should be two patches, patch 1 above, patch 2 below
>>
>>> typedef struct CoalescedMemoryRange CoalescedMemoryRange;
>>> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
>>> index 9e30e148d6..b61c8f053e 100644
>>> --- a/hw/ppc/spapr_iommu.c
>>> +++ b/hw/ppc/spapr_iommu.c
>>> @@ -170,6 +170,13 @@ static void spapr_tce_notify_flag_changed(MemoryRegion
>>> *iommu,
>>> }
>>> }
>>>
>>> +static int spapr_tce_get_fd(MemoryRegion *iommu)
>>> +{
>>> + sPAPRTCETable *tcet = container_of(iommu, sPAPRTCETable, iommu);
>>> +
>>> + return tcet->fd;
>>
>>
>> This would then be:
>>
>> return type == SPAPR_IOMMU_TABLE_FD ? tcet->fd : -1;
>>
>>> +}
>>> +
>>> static int spapr_tce_table_post_load(void *opaque, int version_id)
>>> {
>>> sPAPRTCETable *tcet = SPAPR_TCE_TABLE(opaque);
>>> @@ -251,6 +258,7 @@ static MemoryRegionIOMMUOps spapr_iommu_ops = {
>>> .translate = spapr_tce_translate_iommu,
>>> .get_min_page_size = spapr_tce_get_min_page_size,
>>> .notify_flag_changed = spapr_tce_notify_flag_changed,
>>> + .get_fd = spapr_tce_get_fd,
>>> };
>>>
>>> static int spapr_tce_table_realize(DeviceState *dev)
>>
>
--
Alexey
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