RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1672188 - AMD SEV: Add new managed file /dev/sev for svirt_t
Summary: AMD SEV: Add new managed file /dev/sev for svirt_t
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: selinux-policy
Version: 8.0
Hardware: Unspecified
OS: Linux
high
high
Target Milestone: rc
: 8.0
Assignee: Lukas Vrabec
QA Contact: Milos Malik
URL:
Whiteboard:
Depends On:
Blocks: 1654309 1665400 1671791
TreeView+ depends on / blocked
 
Reported: 2019-02-04 08:14 UTC by Erik Skultety
Modified: 2019-06-14 01:12 UTC (History)
7 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2019-06-14 01:12:50 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description Erik Skultety 2019-02-04 08:14:56 UTC 
Description of problem:
By default, /dev/sev device has file context device_t which will trigger an AVC for svirt_t. We need a new label for the device, e.g. sev_device_t (using kvm_device_t as precedent) and a rule to allow svirt_t access. 

Version-Release number of selected component (if applicable):
3.14.1-51.el8

How reproducible:


Steps to Reproduce:
1. remove cached libvirt capabilities

# rm -f /var/cache/libvirt/qemu/capabilities/*

2. restart libvirtd

# systemctl restart libvirtd

3. check domain capabilities

# virsh domcapabilities

...
<features>
  ...
  <sev supported='no'/>
  ...
</features>
...

Actual results:
QEMU reports that SEV feature is unavailable on the platform because it gets EPERM when it tries to open the device during probing.

Expected results:

...
<sev supported='yes'>
  <cbitpos>47</cbitpos>
  <reducedPhysBits>1</reducedPhysBits>
</sev>
...

Additional info:
Comment 4 Erik Skultety 2019-02-04 14:41:49 UTC 
> Steps to Reproduce:
> 1. remove cached libvirt capabilities
> 
> # rm -f /var/cache/libvirt/qemu/capabilities/*
> 
> 2. restart libvirtd
> 
> # systemctl restart libvirtd
> 
> 3. check domain capabilities
> 
> # virsh domcapabilities
> 
> ...
> <features>
>   ...
>   <sev supported='no'/>
>   ...
> </features>
> ...

Please ignore ^these steps which are wrong and were caused by some left-over settings on the testing machine, follow these steps instead:

Prerequisite: whatever version of libvirt that fixed https://bugzilla.redhat.com/show_bug.cgi?id=1665400

1) enable the SEV feature in a VM XML:

//Set memory hard_limit setting, 256MiB and more of what the currentMemory value says should do
...
 <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <memtune>
    <hard_limit unit='KiB'>4456448</hard_limit>
  </memtune>
...

//All virtio devices need to add a <driver iommu='on'/> element
...
  <devices>
  ...
    <controller type='virtio-serial' index='0'>
      <driver iommu='on'/>
    </controller>
    ...
    <controller type='scsi' index='0' model='virtio-scsi'>
      <driver iommu='on'/>
    </controller>
    ...
    <memballoon model='virtio'>
      <driver iommu='on'/>
    </memballoon>
    ...
    <rng model='virtio'>
      ...
      <driver iommu='on'/>
    </rng>
  ...
  </devices>

//Add the launchSecurity element to enable SEV
...
  </devices>
  <launchSecurity type='sev'>
    <cbitpos>47</cbitpos>
    <reducedPhysBits>1</reducedPhysBits>
    <policy>0x0001</policy>
  </launchSecurity>
...

2) upon successful edit of the XML, start the VM:

# virsh start <my_domain>
error: Failed to start domain <my_domain>
error: internal error: process exited while connecting to monitor: 2019-02-04T14:17:55.700481Z qemu-kvm: sev_guest_init: Failed to open /dev/sev 'Permission denied'         
2019-02-04T14:17:55.701107Z qemu-kvm: failed to initialize KVM: Operation not permitted       

Actual results:
QEMU fails to start a SEV VM because it fails to open /dev/sev device.

Expected results:
QEMU can start a SEV VM successfully.

Additional info:
The current SELinux context of /dev/sev is as follows: system_u:object_r:device_t:s0, qemu-kvm which runs as svirt_t is denied access to device_t:

type=AVC msg=audit(1549289875.700:1137): avc:  denied  { read write } for  pid=92694 comm="qemu-kvm" name="sev" dev="tmpfs" ino=455238 scontext=system_u:system_r:svirt_t:s0:c691,c888 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=0
Note You need to log in before you can comment on or make changes to this bug.