Re: [PATCH v17 059/116] KVM: TDX: Create initial guest memory

[Binbin Wu]

On 11/17/2023 8:04 AM, Isaku Yamahata wrote:
> On Thu, Nov 16, 2023 at 02:35:33PM +0800,
> Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> wrote:
>
> > On 11/7/2023 10:56 PM, isaku.yamahata@xxxxxxxxx wrote:
> > > From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > >
> > > Because the guest memory is protected in TDX, the creation of the initial
> > > guest memory requires a dedicated TDX module API, tdh_mem_page_add, instead
> > > of directly copying the memory contents into the guest memory in the case
> > > of the default VM type.  KVM MMU page fault handler callback,
> > > private_page_add, handles it.
> > >
> > > Define new subcommand, KVM_TDX_INIT_MEM_REGION, of VM-scoped
> > > KVM_MEMORY_ENCRYPT_OP.  It assigns the guest page, copies the initial
> > > memory contents into the guest memory, encrypts the guest memory.  At the
> > > same time, optionally it extends memory measurement of the TDX guest.  It
> > > calls the KVM MMU page fault(EPT-violation) handler to trigger the
> > > callbacks for it.
> > >
> > > Reported-by: gkirkpatrick@xxxxxxxxxx
> > > Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > >
> > > ---
> > > v15 -> v16:
> > > - add check if nr_pages isn't large with
> > >     (nr_page << PAGE_SHIFT) >> PAGE_SHIFT
> > >
> > > v14 -> v15:
> > > - add a check if TD is finalized or not to tdx_init_mem_region()
> > > - return -EAGAIN when partial population
> > > ---
> > >    arch/x86/include/uapi/asm/kvm.h       |   9 ++
> > >    arch/x86/kvm/mmu/mmu.c                |   1 +
> > >    arch/x86/kvm/vmx/tdx.c                | 167 +++++++++++++++++++++++++-
> > >    arch/x86/kvm/vmx/tdx.h                |   2 +
> > >    tools/arch/x86/include/uapi/asm/kvm.h |   9 ++
> > >    5 files changed, 185 insertions(+), 3 deletions(-)
> > [...]
> > > +static int tdx_sept_page_add(struct kvm *kvm, gfn_t gfn,
> > > +			     enum pg_level level, kvm_pfn_t pfn)
> > For me, the function name is a bit confusing.
> > I would relate it to a SEPT table page instead of a normal private page if
> > only by the function name.
> >
> > Similar to tdx_sept_page_aug(), though it's less confusing due to there is
> > no seam call to aug a sept table page.
> How about tdx_mem_page_{add, aug}()?

It looks good to me.