Despite efforts to make the virt-qemu-sev-validate tool friendly, it is
a certainty that almost everyone who tries it will hit false negative
results, getting a failure despite the VM being trustworthy.
Diagnosing these problems is no easy matter, especially for those not
familiar with SEV/SEV-ES in general. This extra docs text attempts to
set out a checklist of items to look at to identify what went wrong.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
It is possible to build OVMF for SEV with an embedded Grub that can
fetch LUKS disk secrets. This adds support for injecting secrets in
the required format.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When validating a SEV-ES guest, we need to know the CPU count and VMSA
state. We can get the CPU count directly from libvirt's guest info. The
VMSA state can be constructed automatically if we query the CPU SKU from
host capabilities XML. Neither of these is secure, however, so this
behaviour is restricted.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The VMSA files contain the expected CPU register state for the VM. Their
content varies based on a few pieces of the stack
- AMD CPU architectural initial state
- KVM hypervisor VM CPU initialization
- QEMU userspace VM CPU initialization
- AMD CPU SKU (family/model/stepping)
The first three pieces of information we can obtain through code
inspection. The last piece of information we can take on the command
line. This allows a user to validate a SEV-ES guest merely by providing
the CPU SKU information, using --cpu-family, --cpu-model,
--cpu-stepping. This avoids the need to obtain or construct VMSA files
directly.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
With the SEV-ES policy the VMSA state of each vCPU must be included in
the measured data. The VMSA state can be generated using the 'sevctl'
tool, by telling it a QEMU VMSA is required, and passing the hypevisor's
CPU SKU (family, model, stepping).
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When connected to libvirt we can validate that the guest configuration
has the kernel hashes property enabled, otherwise including the kernel
GUID table in our expected measurements is not likely to match the
actual measurement.
When running locally we can also automatically detect the kernel/initrd
paths, along with the cmdline string from the XML.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
When doing direct kernel boot we need to include the kernel, initrd and
cmdline in the measurement.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Accept information about a connection to libvirt and a guest on the
command line. Talk to libvirt to obtain the running guest state and
automatically detect as much configuration as possible.
It will refuse to use a libvirt connection that is thought to be local
to the current machine, as running this tool on the hypervisor itself is
not considered secure. This can be overridden using the --insecure flag.
When querying the guest, it will also analyse the XML configuration in
an attempt to detect any options that are liable to be mistakes. For
example the NVRAM being measured should not have a persistent varstore.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The virt-qemu-sev-validate program will compare a reported SEV/SEV-ES
domain launch measurement, to a computed launch measurement. This
determines whether the domain has been tampered with during launch.
This initial implementation requires all inputs to be provided
explicitly, and as such can run completely offline, without any
connection to libvirt.
The tool is placed in the libvirt-client-qemu sub-RPM since it is
specific to the QEMU driver.
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
