Re: [PATCHv5 3/4] x86/tdx: Dynamically disable SEPT violations from causing #VEs

[Kirill A. Shutemov]

On Wed, Jul 03, 2024 at 03:22:35PM +0300, Nikolay Borisov wrote:
> 
> 
> On 24.06.24 г. 14:41 ч., Kirill A. Shutemov wrote:
> 
> <snip>
> 
> 
> 
> > --- a/arch/x86/include/asm/shared/tdx.h
> > +++ b/arch/x86/include/asm/shared/tdx.h
> > @@ -19,9 +19,17 @@
> >   #define TDG_VM_RD			7
> >   #define TDG_VM_WR			8
> > -/* TDCS fields. To be used by TDG.VM.WR and TDG.VM.RD module calls */
> > +/* TDX TD-Scope Metadata. To be used by TDG.VM.WR and TDG.VM.RD */
> > +#define TDCS_CONFIG_FLAGS		0x1110000300000016
> > +#define TDCS_TD_CTLS			0x1110000300000017
> >   #define TDCS_NOTIFY_ENABLES		0x9100000000000010
> > +/* TDCS_CONFIG_FLAGS bits */
> > +#define TDCS_CONFIG_FLEXIBLE_PENDING_VE	BIT_ULL(1)
> 
> 
> So where is this bit documented, because in td_scope_metadata.json
> CONFIG_FLAGS' individual bits aren't documented. All other TDX docs refer to
> the ABI .json file.
> 
> Landing code for undocumented bits unfortunately precludes any quality
> review on behalf of independent parties.
> 
> > +
> > +/* TDCS_TD_CTLS bits */
> > +#define TD_CTLS_PENDING_VE_DISABLE	BIT_ULL(0)
> 
> In contrast the TD_CTLS bits are documented in the same .json file.

Yes, TDX documentation is lacking here. I hope it will be fixed in the
next version.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov