On Fri, Feb 12, 2021, Andy Lutomirski wrote: > On Fri, Feb 5, 2021 at 3:39 PM Kuppuswamy Sathyanarayanan > <[email protected]> wrote: > > > > From: "Kirill A. Shutemov" <[email protected]> > > > > The TDX module injects #VE exception to the guest TD in cases of > > disallowed instructions, disallowed MSR accesses and subset of CPUID > > leaves. Also, it's theoretically possible for CPU to inject #VE > > exception on EPT violation, but the TDX module makes sure this does > > not happen, as long as all memory used is properly accepted using > > TDCALLs. > > By my very cursory reading of the TDX arch specification 9.8.2, > "Secure" EPT violations don't send #VE. But the docs are quite > unclear, or at least the docs I found are.
The version I have also states that SUPPRESS_VE is always set. So either there was a change in direction, or the public docs need to be updated. Lazy accept requires a #VE, either from hardware or from the module. The latter would require walking the Secure EPT tables on every EPT violation... > What happens if the guest attempts to access a secure GPA that is not > ACCEPTed? For example, suppose the VMM does THH.MEM.PAGE.REMOVE on a secure > address and the guest accesses it, via instruction fetch or data access. > What happens? Well, as currently written in the spec, it will generate an EPT violation and the host will have no choice but to kill the guest.
