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| author |   Nathan Tempelman <natet@google.com> | 2021-04-08 22:32:14 +0000 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2021-04-21 12:20:02 -0400 |
| commit | 54526d1fd59338fd6a381dbd806b7ccbae3aa4aa (patch) | |
| tree | 658e7a672bba151def521aafa5433c5cd04bed1b /include/uapi | |
| parent | nSVM: Check addresses of MSR and IO permission maps (diff) | |
| download | linux-dev-54526d1fd59338fd6a381dbd806b7ccbae3aa4aa.tar.xz linux-dev-54526d1fd59338fd6a381dbd806b7ccbae3aa4aa.zip | |
KVM: x86: Support KVM VMs sharing SEV context
Add a capability for userspace to mirror SEV encryption context from
one vm to another. On our side, this is intended to support a
Migration Helper vCPU, but it can also be used generically to support
other in-guest workloads scheduled by the host. The intention is for
the primary guest and the mirror to have nearly identical memslots.
The primary benefits of this are that:
1) The VMs do not share KVM contexts (think APIC/MSRs/etc), so they
can't accidentally clobber each other.
2) The VMs can have different memory-views, which is necessary for post-copy
migration (the migration vCPUs on the target need to read and write to
pages, when the primary guest would VMEXIT).
This does not change the threat model for AMD SEV. Any memory involved
is still owned by the primary guest and its initial state is still
attested to through the normal SEV_LAUNCH_* flows. If userspace wanted
to circumvent SEV, they could achieve the same effect by simply attaching
a vCPU to the primary VM.
This patch deliberately leaves userspace in charge of the memslots for the
mirror, as it already has the power to mess with them in the primary guest.
This patch does not support SEV-ES (much less SNP), as it does not
handle handing off attested VMSAs to the mirror.
For additional context, we need a Migration Helper because SEV PSP
migration is far too slow for our live migration on its own. Using
an in-guest migrator lets us speed this up significantly.
Signed-off-by: Nathan Tempelman <natet@google.com>
Message-Id: <20210408223214.2582277-1-natet@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/kvm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 162b7e044c8b..37f0a329da6a 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1080,6 +1080,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_PPC_DAWR1 194 #define KVM_CAP_SET_GUEST_DEBUG2 195 #define KVM_CAP_SGX_ATTRIBUTE 196 +#define KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 197 #ifdef KVM_CAP_IRQ_ROUTING |