On Wed, Apr 26, 2023, James Bottomley wrote: > On Wed, 2023-04-26 at 13:32 +0000, Reshetova, Elena wrote: > > > On Mon, Mar 27, 2023, Carlos Bilbao wrote: > [...] > > > > +provide stronger security guarantees to their clients (usually > > > > referred to +as tenants) by excluding all the CSP's > > > > infrastructure and SW out of the +tenant's Trusted Computing Base > > > > (TCB). > > > > > > This is inaccurate, the provider may still have software and/or > > > hardware in the TCB. > > > > Well, this is the end goal where we want to be, If by "we" you mean Intel and AMD, then yes, that is probably a true statement. But those goals have nothing to do with security. > > the practical deployment can differ of course. We can rephrase that it > > "allows to exclude all the CSP's infrastructure and SW out of tenant's > > TCB." > > That's getting even more inaccurate. To run in a Cloud with CoCo you > usually have to insert some provided code, like OVMF and, for AMD, the > SVSM. These are often customized by the CSP to suit the cloud > infrastructure, so you're running their code. The goal, I think, is to > make sure you only run code you trust (some of which may come from the > CSP) in your TCB, which is very different from the statement above. Yes. And taking things a step further, if we were to ask security concious users what they would choose to have in their TCB: (a) closed-source firmware written by a hardware vendor, or (b) open-source software that is provided by CSPs, I am betting the overwhelming majority would choose (b).
