Re: [PATCH v2 4/8] riscv: mm: Add memory hotplugging support

["Björn Töpel" <bjorn@kernel.org>]

Alexandre Ghiti <alexghiti@rivosinc.com> writes:

> On Tue, May 14, 2024 at 4:05 PM Björn Töpel <bjorn@kernel.org> wrote:

>> +int __ref arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params)
>> +{
>> +       int ret;
>> +
>> +       create_linear_mapping_range(start, start + size, 0, &params->pgprot);
>> +       flush_tlb_all();
>> +       ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, params);
>> +       if (ret) {
>> +               remove_linear_mapping(start, size);
>> +               return ret;
>> +       }
>> +
>
> You need to flush the TLB here too since __add_pages() populates the
> page table with the new vmemmap mapping (only because riscv allows to
> cache invalid entries, I'll adapt this in my next version of Svvptc
> support).
>
>> +       max_pfn = PFN_UP(start + size);
>> +       max_low_pfn = max_pfn;
>> +       return 0;
>> +}
>> +
>> +void __ref arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
>> +{
>> +       __remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT, altmap);
>> +       remove_linear_mapping(start, size);
>
> You need to flush the TLB here too.

I'll address all of the above in the next version. Thanks for reviewing
the series!


Björn