Re: [PATCH RFC 04/10] intel_iommu: Second Stage Access Dirty bit support

[Joao Martins <joao.m.martins@oracle.com>]

On 5/4/22 21:11, Peter Xu wrote:
> Hi, Joao,
> 
> On Thu, Apr 28, 2022 at 10:13:45PM +0100, Joao Martins wrote:
>> +/* Get the content of a spte located in @base_addr[@index] */
>> +static uint64_t vtd_set_slpte(dma_addr_t base_addr, uint32_t index,
>> +                              uint64_t slpte)
>> +{
>> +
>> +    if (dma_memory_write(&address_space_memory,
>> +                         base_addr + index * sizeof(slpte), &slpte,
>> +                         sizeof(slpte), MEMTXATTRS_UNSPECIFIED)) {
>> +        slpte = (uint64_t)-1;
>> +        return slpte;
>> +    }
>> +
>> +    return vtd_get_slpte(base_addr, index);
>> +}
> 
> Could I ask when the write succeeded, why need to read slpte again?

We don't, I should delete this.

Perhaps I was obsessed that what I set is what I get in the end and this
was a remnant of it.