Re: [PATCH v7 01/15] swiotlb: Refactor swiotlb init functions

Claire Chang
2021-05-20T06:45:54Z

On Thu, May 20, 2021 at 2:50 AM Florian Fainelli <f.fainelli@gmail.com> wrote:
>
>
>
> On 5/17/2021 11:42 PM, Claire Chang wrote:
> > Add a new function, swiotlb_init_io_tlb_mem, for the io_tlb_mem struct
> > initialization to make the code reusable.
> >
> > Note that we now also call set_memory_decrypted in swiotlb_init_with_tbl.
> >
> > Signed-off-by: Claire Chang <tientzu@chromium.org>
> > ---
> > kernel/dma/swiotlb.c | 51 ++++++++++++++++++++++----------------------
> > 1 file changed, 25 insertions(+), 26 deletions(-)
> >
> > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> > index 8ca7d505d61c..d3232fc19385 100644
> > --- a/kernel/dma/swiotlb.c
> > +++ b/kernel/dma/swiotlb.c
> > @@ -168,9 +168,30 @@ void __init swiotlb_update_mem_attributes(void)
> > memset(vaddr, 0, bytes);
> > }
> >
> > -int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
> > +static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
> > + unsigned long nslabs, bool late_alloc)
> > {
> > + void *vaddr = phys_to_virt(start);
> > unsigned long bytes = nslabs << IO_TLB_SHIFT, i;
> > +
> > + mem->nslabs = nslabs;
> > + mem->start = start;
> > + mem->end = mem->start + bytes;
> > + mem->index = 0;
> > + mem->late_alloc = late_alloc;
> > + spin_lock_init(&mem->lock);
> > + for (i = 0; i < mem->nslabs; i++) {
> > + mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);
> > + mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
> > + mem->slots[i].alloc_size = 0;
> > + }
> > +
> > + set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
> > + memset(vaddr, 0, bytes);
>
> You are doing an unconditional set_memory_decrypted() followed by a
> memset here, and then:
>
> > +}
> > +
> > +int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
> > +{
> > struct io_tlb_mem *mem;
> > size_t alloc_size;
> >
> > @@ -186,16 +207,8 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
> > if (!mem)
> > panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
> > __func__, alloc_size, PAGE_SIZE);
> > - mem->nslabs = nslabs;
> > - mem->start = __pa(tlb);
> > - mem->end = mem->start + bytes;
> > - mem->index = 0;
> > - spin_lock_init(&mem->lock);
> > - for (i = 0; i < mem->nslabs; i++) {
> > - mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);
> > - mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
> > - mem->slots[i].alloc_size = 0;
> > - }
> > +
> > + swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, false);
>
> You convert this call site with swiotlb_init_io_tlb_mem() which did not
> do the set_memory_decrypted()+memset(). Is this okay or should
> swiotlb_init_io_tlb_mem() add an additional argument to do this
> conditionally?

I'm actually not sure if this it okay. If not, will add an additional
argument for it.

> --
> Florian