[PATCH v13 23/35] KVM: x86: Add support for "protected VMs" that can utilize private memory

[Paolo Bonzini]

On 10/27/23 20:22, Sean Christopherson wrote:
> Add a new x86 VM type, KVM_X86_SW_PROTECTED_VM, to serve as a development
> and testing vehicle for Confidential (CoCo) VMs, and potentially to even
> become a "real" product in the distant future, e.g. a la pKVM.
> 
> The private memory support in KVM x86 is aimed at AMD's SEV-SNP and
> Intel's TDX, but those technologies are extremely complex (understatement),
> difficult to debug, don't support running as nested guests, and require
> hardware that's isn't universally accessible.  I.e. relying SEV-SNP or TDX
> for maintaining guest private memory isn't a realistic option.
> 
> At the very least, KVM_X86_SW_PROTECTED_VM will enable a variety of
> selftests for guest_memfd and private memory support without requiring
> unique hardware.
> 
> Signed-off-by: Sean Christopherson <seanjc at google.com>

Reviewed-by: Paolo Bonzini <pbonzini at redhat.com>

with one nit:

> +---------------------
> +
> +:Capability: KVM_CAP_MEMORY_ATTRIBUTES
> +:Architectures: x86
> +:Type: system ioctl
> +
> +This capability returns a bitmap of support VM types.  The 1-setting of bit @n

s/support/supported/

Paolo