Re: [PATCH Part1 v5 17/38] x86/mm: Add support to validate memory when changing C-bit

[Brijesh Singh]

On 8/25/21 6:06 AM, Borislav Petkov wrote:
> I really meant putting the beginning of that string at the very first
> position on the line:
>
>                  if (WARN(hdr->end_entry > end_entry || cur_entry > hdr->cur_entry,
> "SEV-SNP: PSC processing going backward, end_entry %d (got %d) cur_entry %d (got %d)\n",
>                           end_entry, hdr->end_entry, cur_entry, hdr->cur_entry)) {
>
> Exactly like this!

Noted.

> ...
>
> > +static void set_page_state(unsigned long vaddr, unsigned int npages, int op)
> > +{
> > +	unsigned long vaddr_end, next_vaddr;
> > +	struct snp_psc_desc *desc;
> > +
> > +	vaddr = vaddr & PAGE_MASK;
> > +	vaddr_end = vaddr + (npages << PAGE_SHIFT);
> > +
> > +	desc = kmalloc(sizeof(*desc), GFP_KERNEL_ACCOUNT);
>
> And again, from previous review:
>
> kzalloc() so that you don't have to memset() later in
> __set_page_state().

I replied to your previous comment. Depending on the npages value, the 
__set_page_state() will be called multiple times and on each call it 
needs to clear desc before populate it. So, I do not see strong reason 
to use kzalloc() during the desc allocation. I thought you were okay 
with that explanation.


> > +	if (!desc)
> > +		panic("SEV-SNP: failed to alloc memory for PSC descriptor\n");
>
> "allocate" fits just fine too.

Noted.

thanks