Re: [PATCH v6 00/14] Add AMD SEV guest live migration support

[Ashish Kalra <ashish.kalra@amd.com>]

This is applied on top of Linux 5.6, as per commit below :

commit 7111951b8d4973bda27ff663f2cf18b663d15b48 (tag: v5.6, origin/master, origin/HEAD)
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Mar 29 15:25:41 2020 -0700

    Linux 5.6

 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Thanks,
Ashish

On Mon, Mar 30, 2020 at 12:24:46PM -0500, Venu Busireddy wrote:
> On 2020-03-30 06:19:27 +0000, Ashish Kalra wrote:
> > From: Ashish Kalra <ashish.kalra@amd.com>
> > 
> > The series add support for AMD SEV guest live migration commands. To protect the
> > confidentiality of an SEV protected guest memory while in transit we need to
> > use the SEV commands defined in SEV API spec [1].
> > 
> > SEV guest VMs have the concept of private and shared memory. Private memory
> > is encrypted with the guest-specific key, while shared memory may be encrypted
> > with hypervisor key. The commands provided by the SEV FW are meant to be used
> > for the private memory only. The patch series introduces a new hypercall.
> > The guest OS can use this hypercall to notify the page encryption status.
> > If the page is encrypted with guest specific-key then we use SEV command during
> > the migration. If page is not encrypted then fallback to default.
> > 
> > The patch adds new ioctls KVM_{SET,GET}_PAGE_ENC_BITMAP. The ioctl can be used
> > by the qemu to get the page encrypted bitmap. Qemu can consult this bitmap
> > during the migration to know whether the page is encrypted.
> > 
> > [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdeveloper.amd.com%2Fwp-content%2Fresources%2F55766.PDF&amp;data=02%7C01%7CAshish.Kalra%40amd.com%7Cb87828d7e1eb41fe401c08d7d4cf4937%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637211859771455979&amp;sdata=yN1OrvcuNb%2F8JAaLwlf2pIJtEvBRFOSvTKPYWz9ASUY%3D&amp;reserved=0
> > 
> > Changes since v5:
> > - Fix build errors as
> >   Reported-by: kbuild test robot <lkp@intel.com>
> 
> Which upstream tag should I use to apply this patch set? I tried the
> top of Linus's tree, and I get the following error when I apply this
> patch set.
> 
> $ git am PATCH-v6-01-14-KVM-SVM-Add-KVM_SEV-SEND_START-command.mbox
> Applying: KVM: SVM: Add KVM_SEV SEND_START command
> Applying: KVM: SVM: Add KVM_SEND_UPDATE_DATA command
> Applying: KVM: SVM: Add KVM_SEV_SEND_FINISH command
> Applying: KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command
> error: patch failed: Documentation/virt/kvm/amd-memory-encryption.rst:375
> error: Documentation/virt/kvm/amd-memory-encryption.rst: patch does not apply
> error: patch failed: arch/x86/kvm/svm.c:7632
> error: arch/x86/kvm/svm.c: patch does not apply
> Patch failed at 0004 KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command
> 
> Thanks,
> 
> Venu
> 
> > 
> > Changes since v4:
> > - Host support has been added to extend KVM capabilities/feature bits to 
> >   include a new KVM_FEATURE_SEV_LIVE_MIGRATION, which the guest can
> >   query for host-side support for SEV live migration and a new custom MSR
> >   MSR_KVM_SEV_LIVE_MIG_EN is added for guest to enable the SEV live
> >   migration feature.
> > - Ensure that _bss_decrypted section is marked as decrypted in the
> >   page encryption bitmap.
> > - Fixing KVM_GET_PAGE_ENC_BITMAP ioctl to return the correct bitmap
> >   as per the number of pages being requested by the user. Ensure that
> >   we only copy bmap->num_pages bytes in the userspace buffer, if
> >   bmap->num_pages is not byte aligned we read the trailing bits
> >   from the userspace and copy those bits as is. This fixes guest
> >   page(s) corruption issues observed after migration completion.
> > - Add kexec support for SEV Live Migration to reset the host's
> >   page encryption bitmap related to kernel specific page encryption
> >   status settings before we load a new kernel by kexec. We cannot
> >   reset the complete page encryption bitmap here as we need to
> >   retain the UEFI/OVMF firmware specific settings.
> > 
> > Changes since v3:
> > - Rebasing to mainline and testing.
> > - Adding a new KVM_PAGE_ENC_BITMAP_RESET ioctl, which resets the 
> >   page encryption bitmap on a guest reboot event.
> > - Adding a more reliable sanity check for GPA range being passed to
> >   the hypercall to ensure that guest MMIO ranges are also marked
> >   in the page encryption bitmap.
> > 
> > Changes since v2:
> >  - reset the page encryption bitmap on vcpu reboot
> > 
> > Changes since v1:
> >  - Add support to share the page encryption between the source and target
> >    machine.
> >  - Fix review feedbacks from Tom Lendacky.
> >  - Add check to limit the session blob length.
> >  - Update KVM_GET_PAGE_ENC_BITMAP icotl to use the base_gfn instead of
> >    the memory slot when querying the bitmap.
> > 
> > Ashish Kalra (3):
> >   KVM: x86: Introduce KVM_PAGE_ENC_BITMAP_RESET ioctl
> >   KVM: x86: Introduce new KVM_FEATURE_SEV_LIVE_MIGRATION feature &
> >     Custom MSR.
> >   KVM: x86: Add kexec support for SEV Live Migration.
> > 
> > Brijesh Singh (11):
> >   KVM: SVM: Add KVM_SEV SEND_START command
> >   KVM: SVM: Add KVM_SEND_UPDATE_DATA command
> >   KVM: SVM: Add KVM_SEV_SEND_FINISH command
> >   KVM: SVM: Add support for KVM_SEV_RECEIVE_START command
> >   KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command
> >   KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command
> >   KVM: x86: Add AMD SEV specific Hypercall3
> >   KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall
> >   KVM: x86: Introduce KVM_GET_PAGE_ENC_BITMAP ioctl
> >   mm: x86: Invoke hypercall when page encryption status is changed
> >   KVM: x86: Introduce KVM_SET_PAGE_ENC_BITMAP ioctl
> > 
> >  .../virt/kvm/amd-memory-encryption.rst        | 120 +++
> >  Documentation/virt/kvm/api.rst                |  62 ++
> >  Documentation/virt/kvm/cpuid.rst              |   4 +
> >  Documentation/virt/kvm/hypercalls.rst         |  15 +
> >  Documentation/virt/kvm/msr.rst                |  10 +
> >  arch/x86/include/asm/kvm_host.h               |  10 +
> >  arch/x86/include/asm/kvm_para.h               |  12 +
> >  arch/x86/include/asm/paravirt.h               |  10 +
> >  arch/x86/include/asm/paravirt_types.h         |   2 +
> >  arch/x86/include/uapi/asm/kvm_para.h          |   5 +
> >  arch/x86/kernel/kvm.c                         |  32 +
> >  arch/x86/kernel/paravirt.c                    |   1 +
> >  arch/x86/kvm/cpuid.c                          |   3 +-
> >  arch/x86/kvm/svm.c                            | 699 +++++++++++++++++-
> >  arch/x86/kvm/vmx/vmx.c                        |   1 +
> >  arch/x86/kvm/x86.c                            |  43 ++
> >  arch/x86/mm/mem_encrypt.c                     |  69 +-
> >  arch/x86/mm/pat/set_memory.c                  |   7 +
> >  include/linux/psp-sev.h                       |   8 +-
> >  include/uapi/linux/kvm.h                      |  53 ++
> >  include/uapi/linux/kvm_para.h                 |   1 +
> >  21 files changed, 1157 insertions(+), 10 deletions(-)
> > 
> > -- 
> > 2.17.1
> >