On 8/25/20 2:05 PM, Tom Lendacky wrote:
> From: Tom Lendacky <thomas.lendacky@amd.com>
>
> This patch series provides support for launching an SEV-ES guest.
I've made the changes associated with the checkpatch script output. I'll
wait a few more days for other feedback before submitting a v2.
Sorry about the miss in regards to running checkpatch.
Thanks,
Tom
>
> Secure Encrypted Virtualization - Encrypted State (SEV-ES) expands on the
> SEV support to protect the guest register state from the hypervisor. See
> "AMD64 Architecture Programmer's Manual Volume 2: System Programming",
> section "15.35 Encrypted State (SEV-ES)" [1].
>
> In order to allow a hypervisor to perform functions on behalf of a guest,
> there is architectural support for notifying a guest's operating system
> when certain types of VMEXITs are about to occur. This allows the guest to
> selectively share information with the hypervisor to satisfy the requested
> function. The notification is performed using a new exception, the VMM
> Communication exception (#VC). The information is shared through the
> Guest-Hypervisor Communication Block (GHCB) using the VMGEXIT instruction.
> The GHCB format and the protocol for using it is documented in "SEV-ES
> Guest-Hypervisor Communication Block Standardization" [2].
>
> The main areas of the Qemu code that are updated to support SEV-ES are
> around the SEV guest launch process and AP booting in order to support
> booting multiple vCPUs.
>
> There are no new command line switches required. Instead, the desire for
> SEV-ES is presented using the SEV policy object. Bit 2 of the SEV policy
> object indicates that SEV-ES is required.
>
> The SEV launch process is updated in two ways. The first is that a the
> KVM_SEV_ES_INIT ioctl is used to initialize the guest instead of the
> standard KVM_SEV_INIT ioctl. The second is that before the SEV launch
> measurement is calculated, the LAUNCH_UPDATE_VMSA SEV API is invoked for
> each vCPU that Qemu has created. Once the LAUNCH_UPDATE_VMSA API has been
> invoked, no direct changes to the guest register state can be made.
>
> AP booting poses some interesting challenges. The INIT-SIPI-SIPI sequence
> is typically used to boot the APs. However, the hypervisor is not allowed
> to update the guest registers. For the APs, the reset vector must be known
> in advance. An OVMF method to provide a known reset vector address exists
> by providing an SEV information block, identified by UUID, near the end of
> the firmware [3]. OVMF will program the jump to the actual reset vector in
> this area of memory. Since the memory location is known in advance, an AP
> can be created with the known reset vector address as its starting CS:IP.
> The GHCB document [2] talks about how SMP booting under SEV-ES is
> performed.
>
> [1] https://www.amd.com/system/files/TechDocs/24593.pdf
> [2] https://developer.amd.com/wp-content/resources/56421.pdf
> [3] 30937f2f98c4 ("OvmfPkg: Use the SEV-ES work area for the SEV-ES AP reset vector")
> https://github.com/tianocore/edk2/commit/30937f2f98c42496f2f143fe8374ae7f7e684847
>
> ---
>
> These patches are based on commit:
> d0ed6a69d3 ("Update version for v5.1.0 release")
>
> (I tried basing on the latest Qemu commit, but I was having build issues
> that level)
>
> A version of the tree can be found at:
> https://github.com/AMDESE/qemu/tree/sev-es-v9
>
> Tom Lendacky (4):
> sev/i386: Add initial support for SEV-ES
> sev/i386: Allow AP booting under SEV-ES
> sev/i386: Don't allow a system reset under an SEV-ES guest
> sev/i386: Enable an SEV-ES guest based on SEV policy
>
> accel/kvm/kvm-all.c | 68 ++++++++++++++++++++++++++++
> accel/stubs/kvm-stub.c | 5 +++
> hw/i386/pc_sysfw.c | 10 ++++-
> include/sysemu/cpus.h | 2 +
> include/sysemu/hw_accel.h | 4 ++
> include/sysemu/kvm.h | 18 ++++++++
> include/sysemu/sev.h | 2 +
> softmmu/cpus.c | 5 +++
> softmmu/vl.c | 5 ++-
> target/i386/cpu.c | 1 +
> target/i386/kvm.c | 2 +
> target/i386/sev-stub.c | 5 +++
> target/i386/sev.c | 95 ++++++++++++++++++++++++++++++++++++++-
> target/i386/sev_i386.h | 1 +
> 14 files changed, 219 insertions(+), 4 deletions(-)
>