igt/gem_ctx_isolation: Test INSTPM back to gen6

Lionel pointed out that INSTPM was context saved, at least from gen6,
not from gen9. The only caveat is that INSTPM is a masked register (the
upper 16bits are a write-enable mask, the lower 16bits the value to
change) and also contains a read-only counter bit (which counts flushes,
and so flip flops between batches). Being a non-privileged register that
userspace wants to manipulate, it is writable and readable from a
userspace batch, so we can test whether or not a write from one context
is visible from a second.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

0 files changed, 0 insertions, 0 deletions