Re: [PATCH v11 08/20] x86/virt/tdx: Get information about TDX module and TDX-capable memory

[Isaku Yamahata]

On Fri, Jun 09, 2023 at 02:54:41AM +0300,
"kirill.shutemov@xxxxxxxxxxxxxxx" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:

> On Thu, Jun 08, 2023 at 04:29:19PM -0700, Isaku Yamahata wrote:
> > On Thu, Jun 08, 2023 at 02:41:28PM +0300,
> > "kirill.shutemov@xxxxxxxxxxxxxxx" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
> > 
> > > On Thu, Jun 08, 2023 at 02:40:27AM +0000, Huang, Kai wrote:
> > > > On Thu, 2023-06-08 at 03:27 +0300, kirill.shutemov@xxxxxxxxxxxxxxx wrote:
> > > > > On Mon, Jun 05, 2023 at 02:27:21AM +1200, Kai Huang wrote:
> > > > > > For now both 'tdsysinfo_struct' and CMRs are only used during the module
> > > > > > initialization.  But because they are both relatively big, declare them
> > > > > > inside the module initialization function but as static variables.
> > > > > 
> > > > > This justification does not make sense to me. static variables will not be
> > > > > freed after function returned. They will still consume memory.
> > > > > 
> > > > > I think you need to allocate/free memory dynamically, if they are too big
> > > > > for stack.
> > > > 
> > > > 
> > > > I do need to keep tdsysinfo_struct as it will be used by KVM too.
> > > 
> > > Will you pass it down to KVM from this function? Will KVM use the struct
> > > after the function returns?
> > 
> > KVM needs tdsysinfo_struct to create guest TD.  It doesn't require
> > 1024-alignment.
> 
> How KVM gets it from here?

For now, TDX KVM patch series moves the tdsysinfo out of the function, and add
a getter function of it.
As long as KVM can access the info, it doesn't care how its memory is allocated.
static or dynamic.
-- 
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>