Messages in this thread | | | Date | Tue, 22 Feb 2022 01:02:33 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv3 16/32] x86/boot: Allow to hook up alternative port I/O helpers |
| |
On Mon, Feb 21, 2022 at 02:04:33PM -0600, Tom Lendacky wrote: > On 2/18/22 10:17, Kirill A. Shutemov wrote: > > Port I/O instructions trigger #VE in the TDX environment. In response to > > the exception, kernel emulates these instructions using hypercalls. > > > > But during early boot, on the decompression stage, it is cumbersome to > > deal with #VE. It is cleaner to go to hypercalls directly, bypassing #VE > > handling. > > > > Add a way to hook up alternative port I/O helpers in the boot stub. > > This seems like a lot of churn in order to get this all working without > taking a #VE.
Well, it evolved from more concise (but also more hacky) implementation:
https://lore.kernel.org/all/20211214150304.62613-11-kirill.shutemov@linux.intel.com
> How cumbersome is it to get #VE handling working in the decompression > stage? Can you build on any of the support that was added to handle #VC?
We definitely can.
But I still think exception-based implementation is inherently more fragile. I would rather stick with this.
-- Kirill A. Shutemov
| |