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  • Anton Anton anjo
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  1. Nov 20, 2017
  3. Nov 19, 2017
    • Greg Kurz's avatar
      spapr: reset DRCs after devices · 82512483
      Greg Kurz authored 
      
A DRC with a pending unplug request releases its associated device at
machine reset time.

In the case of LMB, when all DRCs for a DIMM device have been reset,
the DIMM gets unplugged, causing guest memory to disappear. This may
be very confusing for anything still using this memory.

This is exactly what happens with vhost backends, and QEMU aborts
with:

qemu-system-ppc64: used ring relocated for ring 2
qemu-system-ppc64: qemu/hw/virtio/vhost.c:649: vhost_commit: Assertion
 `r >= 0' failed.

The issue is that each DRC registers a QEMU reset handler, and we
don't control the order in which these handlers are called (ie,
a LMB DRC will unplug a DIMM before the virtio device using the
memory on this DIMM could stop its vhost backend).

To avoid such situations, let's reset DRCs after all devices
have been reset.

Reported-by: default avatarMallesh N. Koti <mallesh@linux.vnet.ibm.com>
Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Reviewed-by: default avatarDaniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
Reviewed-by: default avatarMichael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      82512483
    • Suraj Jitindar Singh's avatar
      target/ppc: Update setting of cpu features to account for compat modes · 7abd43ba
      Suraj Jitindar Singh authored 
      
The device tree nodes ibm,arch-vec-5-platform-support and ibm,pa-features
are used to communicate features of the cpu to the guest operating
system. The properties of each of these are determined based on the
selected cpu model and the availability of hypervisor features.
Currently the compatibility mode of the cpu is not taken into account.

The ibm,arch-vec-5-platform-support node is used to communicate the
level of support for various ISAv3 processor features to the guest
before CAS to inform the guests' request. The available mmu mode should
only be hash unless the cpu is a POWER9 which is not in a prePOWER9
compat mode, in which case the available modes depend on the
accelerator and the hypervisor capabilities.

The ibm,pa-featues node is used to communicate the level of cpu support
for various features to the guest os. This should only contain features
relevant to the operating mode of the processor, that is the selected
cpu model taking into account any compat mode. This means that the
compat mode should be taken into account when choosing the properties of
ibm,pa-features and they should match the compat mode selected, or the
cpu model selected if no compat mode.

Update the setting of these cpu features in the device tree as described
above to properly take into account any compat mode. We use the
ppc_check_compat function which takes into account the current processor
model and the cpu compat mode.

Signed-off-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      7abd43ba
  5. Nov 17, 2017