Re: changing Dom0 data during smc call inside of xen during cache coloring

[Julien Grall <julien@xxxxxxx>]

On 27/09/2023 11:07, Oleg Nikitenko wrote:
> Hello,
Hi,

> It is necessary to change some structure contents from xen.
> I have access to the registers.
> One of them keeps the physical address of the structure.
> But this physical address is valid for Dom0 only.
> Dom0 kernel gets it by the call dma_alloc_coherent
> A lower mentioned scheme does not work.
It is not clear to me what you mean by does not work. Are you getting 
the wrong address?
>              uint64_t paramaddr = (uint64_t)get_user_reg(regs, 2);
>              uint64_t phyaddr = mfn_to_maddr(gfn_to_mfn(current->domain,
>                  gaddr_to_gfn(paramaddr)));
>              phyaddr += (paramaddr & ~PAGE_MASK);
Can you provide a bit more context of what are you trying to do with 
phyaddr afterwards? Are you trying to map it in Xen?
Cheers,

--
Julien Grall