Re: [PATCH 00/21] TDX/SNP part 1 of n, for 6.9

[Paolo Bonzini]

On Wed, Feb 28, 2024 at 2:25 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> On Tue, Feb 27, 2024, Paolo Bonzini wrote:
> > This is a first set of, hopefully non-controversial patches from the
>
> Heh, you jinxed yourself.  :-)

Well I
> > SNP and TDX series.  They cover mostly changes to generic code and new
> > gmem APIs, and in general have already been reviewed when posted by
> > Isaku and Michael.
> >
> > One important change is that the gmem hook for initializing memory
> > is designed to return -EEXIST if the page already exists in the
> > guestmemfd filemap.  The idea is that the special case of
> > KVM_SEV_SNP_LAUNCH_UPDATE, where __kvm_gmem_get_pfn() is used to
> > return an uninitialized page and make it guest-owned, can be be done at
> > most once per page unless the ioctl fails.
> >
> > Of course these patches add a bunch of dead code.  This is intentional
> > because it's the only way to trim the large TDX (and to some extent SNP)
> > series to the point that it's possible to discuss them.  The next step is
> > probably going to be the private<->shared page logic from the TDX series.
> >
> > Paolo
> >
> > Isaku Yamahata (5):
> >   KVM: x86/mmu: Add Suppress VE bit to EPT
> >     shadow_mmio_mask/shadow_present_mask
> >   KVM: VMX: Introduce test mode related to EPT violation VE
> >   KVM: x86/tdp_mmu: Init role member of struct kvm_mmu_page at
> >     allocation
> >   KVM: x86/tdp_mmu: Sprinkle __must_check
> >   KVM: x86/mmu: Pass around full 64-bit error code for KVM page faults
>
> I have a slight tweak to this patch (drop truncation), and a rewritten changelog.
>
> > Michael Roth (2):
> >   KVM: x86: Add gmem hook for invalidating memory
> >   KVM: x86: Add gmem hook for determining max NPT mapping level
> >
> > Paolo Bonzini (6):
> >   KVM: x86/mmu: pass error code back to MMU when async pf is ready
> >   KVM: x86/mmu: Use PFERR_GUEST_ENC_MASK to indicate fault is private
>
> This doesn't work.  The ENC flag gets set on any SNP *capable* CPU, which results
> in false positives for SEV and SEV-ES guests[*].

You didn't look at the patch did you? :) It does check for
has_private_mem (alternatively I could have dropped the bit in SVM
code for SEV and SEV-ES guests).

> I have a medium-sized series to add a KVM-defined synthetic flag, and clean up
> the related code (it also has my slight variation on the 64-bit error code patch).
>
> I'll post my series exactly as I have it, mostly so that I don't need to redo
> testing, but also because it's pretty much a drop-in replacement.  This series
> applies cleanly on top, except for the two obvious conflicts.

Ok, I will check it out. This is exactly why I posted these.

Paolo

> [*] https://lore.kernel.org/all/Zdar_PrV4rzHpcGc@xxxxxxxxxx
>
> >   KVM: guest_memfd: pass error up from filemap_grab_folio
> >   filemap: add FGP_CREAT_ONLY
> >   KVM: x86: Add gmem hook for initializing memory
> >   KVM: guest_memfd: add API to undo kvm_gmem_get_uninit_pfn
> >
> > Sean Christopherson (7):
> >   KVM: x86: Split core of hypercall emulation to helper function
> >   KVM: Allow page-sized MMU caches to be initialized with custom 64-bit
> >     values
> >   KVM: x86/mmu: Replace hardcoded value 0 for the initial value for SPTE
> >   KVM: x86/mmu: Track shadow MMIO value on a per-VM basis
> >   KVM: x86/mmu: Allow non-zero value for non-present SPTE and removed
> >     SPTE
> >   KVM: VMX: Move out vmx_x86_ops to 'main.c' to wrap VMX and TDX
> >   KVM: VMX: Modify NMI and INTR handlers to take intr_info as function
> >     argument
> >
> > Tom Lendacky (1):
> >   KVM: SEV: Use a VMSA physical address variable for populating VMCB
> >
> >  arch/x86/include/asm/kvm-x86-ops.h |   3 +
> >  arch/x86/include/asm/kvm_host.h    |  12 +
> >  arch/x86/include/asm/vmx.h         |  13 +
> >  arch/x86/kvm/Makefile              |   2 +-
> >  arch/x86/kvm/mmu.h                 |   1 +
> >  arch/x86/kvm/mmu/mmu.c             |  55 ++--
> >  arch/x86/kvm/mmu/mmu_internal.h    |   6 +-
> >  arch/x86/kvm/mmu/mmutrace.h        |   2 +-
> >  arch/x86/kvm/mmu/paging_tmpl.h     |   4 +-
> >  arch/x86/kvm/mmu/spte.c            |  16 +-
> >  arch/x86/kvm/mmu/spte.h            |  21 +-
> >  arch/x86/kvm/mmu/tdp_iter.h        |  12 +
> >  arch/x86/kvm/mmu/tdp_mmu.c         |  74 +++--
> >  arch/x86/kvm/svm/sev.c             |   3 +-
> >  arch/x86/kvm/svm/svm.c             |   9 +-
> >  arch/x86/kvm/svm/svm.h             |   1 +
> >  arch/x86/kvm/vmx/main.c            | 168 +++++++++++
> >  arch/x86/kvm/vmx/vmcs.h            |   5 +
> >  arch/x86/kvm/vmx/vmx.c             | 460 +++++++++++------------------
> >  arch/x86/kvm/vmx/vmx.h             |   6 +-
> >  arch/x86/kvm/vmx/x86_ops.h         | 124 ++++++++
> >  arch/x86/kvm/x86.c                 |  69 +++--
> >  include/linux/kvm_host.h           |  25 ++
> >  include/linux/kvm_types.h          |   1 +
> >  include/linux/pagemap.h            |   2 +
> >  mm/filemap.c                       |   4 +
> >  virt/kvm/Kconfig                   |   8 +
> >  virt/kvm/guest_memfd.c             | 120 +++++++-
> >  virt/kvm/kvm_main.c                |  16 +-
> >  29 files changed, 855 insertions(+), 387 deletions(-)
> >  create mode 100644 arch/x86/kvm/vmx/main.c
> >  create mode 100644 arch/x86/kvm/vmx/x86_ops.h
> >
> > --
> > 2.39.0
> >
>