Re: [PATCH v2 0/4] Add guest support for SEV live migration.

[Ashish Kalra]

Hello Boris, Paolo,

Do you have additional comments, feedback on this updated patchset ?

Thanks,
Ashish

On Fri, Apr 23, 2021 at 03:57:37PM +0000, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
> 
> The series adds guest support for SEV live migration.
> 
> 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.
> 
> This section descibes how the SEV live migration feature is negotiated
> between the host and guest, the host indicates this feature support via 
> KVM_FEATURE_CPUID. The guest firmware (OVMF) detects this feature and
> sets a UEFI enviroment variable indicating OVMF support for live
> migration, the guest kernel also detects the host support for this
> feature via cpuid and in case of an EFI boot verifies if OVMF also
> supports this feature by getting the UEFI enviroment variable and if it
> set then enables live migration feature on host by writing to a custom
> MSR, if not booted under EFI, then it simply enables the feature by
> again writing to the custom MSR.
> 
> Changes since v1:
>  - Avoid having an SEV specific variant of kvm_hypercall3() and instead
>    invert the default to VMMCALL.
> 
> Ashish Kalra (3):
>   KVM: x86: invert KVM_HYPERCALL to default to VMMCALL
>   EFI: Introduce the new AMD Memory Encryption GUID.
>   x86/kvm: Add guest support for detecting and enabling SEV Live
>     Migration feature.
> 
> Brijesh Singh (1):
>   mm: x86: Invoke hypercall when page encryption status is changed
> 
>  arch/x86/include/asm/kvm_para.h       |   2 +-
>  arch/x86/include/asm/mem_encrypt.h    |   4 +
>  arch/x86/include/asm/paravirt.h       |   6 ++
>  arch/x86/include/asm/paravirt_types.h |   2 +
>  arch/x86/include/asm/set_memory.h     |   2 +
>  arch/x86/kernel/kvm.c                 | 106 ++++++++++++++++++++++++++
>  arch/x86/kernel/paravirt.c            |   1 +
>  arch/x86/mm/mem_encrypt.c             |  72 ++++++++++++++---
>  arch/x86/mm/pat/set_memory.c          |   7 ++
>  include/linux/efi.h                   |   1 +
>  10 files changed, 193 insertions(+), 10 deletions(-)
> 
> -- 
> 2.17.1
>