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

From: Venu Busireddy
Date: Mon Mar 30 2020 - 13:25:26 EST


On 2020-03-30 06:19:27 +0000, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
>
> 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://developer.amd.com/wp-content/resources/55766.PDF
>
> Changes since v5:
> - Fix build errors as
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>

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
>