Re: [PATCHv2 23/29] x86/tdx: Add helper to convert memory between shared and private

[Kirill A. Shutemov]

On Tue, Feb 08, 2022 at 01:12:45PM +0100, Borislav Petkov wrote:
> On Mon, Jan 24, 2022 at 06:02:09PM +0300, Kirill A. Shutemov wrote:
> > +	if (ret)
> > +		ret = -EIO;
> > +
> > +	if (ret || !enc)
> 
> Is the second case here after the "||" the conversion-to-shared where it
> only needs to notify with MapGPA and return?

Right. Memory accepting is required on the way to private.

I will rewrite and comment this code to make it more readable.

> > +		return ret;
> > +
> > +	/*
> > +	 * For shared->private conversion, accept the page using
> > +	 * TDX_ACCEPT_PAGE TDX module call.
> > +	 */
> > +	while (start < end) {
> > +		/* Try 2M page accept first if possible */
> > +		if (!(start & ~PMD_MASK) && end - start >= PMD_SIZE &&
> > +		    !tdx_accept_page(start, PG_LEVEL_2M)) {
> 
> What happens here if the module doesn't accept the page? No error
> reporting, no error handling, no warning, nada?

If it fails we fallback to 4k accept below.

We only report error if 4k accept fails.

-- 
 Kirill A. Shutemov