These are the new priviledged interfaces to the VMM backends, and expose
some functionality that wasn't previously available.
It's now possible to allocate a chunk of address-space (even all of it),
without causing page tables to be allocated up-front, and then map into
it at arbitrary locations. This is the basic primitive used to support
features such as sparse mapping, or to allow userspace control over its
own address-space, or HMM (where the GPU driver isn't in control of the
address-space layout).
Rather than being tied to a subtle combination of memory object and VMA
properties, arguments that control map flags (ro, kind, etc) are passed
explicitly at map time.
The compatibility hacks to implement the old frontend on top of the new
driver backends have been replaced with something similar to implement
the old frontend's interfaces on top of the new frontend.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This is the common code to support a rework of the VMM backends.
It adds support for more than 2 levels of page table nesting, which
is required to be able to support GP100's MMU layout.
Sparse mappings (that don't cause MMU faults when accessed) are now
supported, where the backend provides it.
Dual-PT handling had to become more sophisticated to support sparse,
but this also allows us to support an optimisation the MMU provides
on GK104 and newer.
Certain operations can now be combined into a single page tree walk
to avoid some overhead, but also enables optimsations like skipping
PTE unmap writes when the PT will be destroyed anyway.
The old backend has been hacked up to forward requests onto the new
backend, if present, so that it's possible to bisect between issues
in the backend changes vs the upcoming frontend changes.
Until the new frontend has been merged, new backends will leak BAR2
page tables on module unload. This is expected, and it's not worth
the effort of hacking around this as it doesn't effect runtime.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
We previously required each VMM user to allocate their own page directory
and fill in the instance block themselves.
It makes more sense to handle this in a common location.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This is the first chunk of the new VMM code that provides the structures
needed to describe a GPU virtual address-space layout, as well as common
interfaces to handle VMM creation, and connecting instances to a VMM.
The constructor now allocates the PD itself, rather than having the user
handle that manually. This won't/can't be used until after all backends
have been ported to these interfaces, so a little bit of memory will be
wasted on Fermi and newer for a couple of commits in the series.
Compatibility has been hacked into the old code to allow each GPU backend
to be ported individually.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
GP100 "big" (which is a funny name, when it supports "even bigger") page
tables are small enough that we want to be able to suballocate them from
a larger block of memory.
This builds on the previous page table cache interfaces so that the VMM
code doesn't need to know the difference.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Builds up and maintains a small cache of each page table size in order
to reduce the frequency of expensive allocations, particularly in the
pathological case where an address range ping-pongs between allocated
and free.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Removes the need to expose internals outside of MMU, and GP100 is both
different, and a lot harder to deal with.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Another transition step to allow finer-grained patches transitioning to
new MMU backends.
Old backends will continue operate as before (accessing nvkm_mem::tag),
and new backends will get a reference to the tags allocated here.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Upcoming MMU changes use nvkm_memory as its basic representation of memory,
so we need to be able to allocate VRAM like this.
The code is basically identical to the current chipset-specific allocators,
minus support for compression tags (which will be handled elsewhere anyway).
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Adds support for 64-bit writes, and optimised filling of buffers with
fixed 32/64-bit values.
These will all be used by the upcoming MMU changes.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
We need to be able to prevent memory from being freed while it's still
mapped in a GPU's address-space.
Will be used by upcoming MMU changes.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Needed by VMM code to determine whether an allocation is compatible with
a given page size (ie. you can't map 4KiB system memory pages into 64KiB
GPU pages).
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Map flags (access, kind, etc) are currently defined in either the VMA,
or the memory object, which turns out to not be ideal for things like
suballocated buffers, etc.
These will become per-map flags instead, so we need to support passing
these arguments in nvkm_memory_map().
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
nvkm_memory is going to be used by the upcoming mmu rework for the basic
representation of a memory allocation, as such, this commit adds support
for comptag allocation to nvkm_memory.
This is very simple for now, in that it requires comptags for the entire
memory allocation even if only certain ranges are compressed.
Support for tracking ranges will be added at a later date.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
We're moving towards having a central place to handle comptag allocation,
and as some GPUs don't have a ram submodule (ie. Tegra), we need to move
the mm somewhere else.
It probably never belonged in ram anyways.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Different sections of VRAM may have different properties (ie. can't be used
for compression/display, can't be mapped, etc).
We currently already support this, but it's a bit magic. This change makes
it more obvious where we're allocating from.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
The accessor functions can change as a result of acquire()/release() calls,
and are protected by any refcounting done there.
Other functions must remain constant, as they can be called any time.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Discovered by accident while working to use BAR2 access to instmem objects
on more paths.
We've apparently been relying on luck up until now!
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Upcoming changes will remove the nvkm_vmm pointer from nvkm_vma, instead
requiring it to be explicitly specified on each operation.
It's not currently possible to get this information for BAR1 mappings,
so let's fix that ahead of time.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Will prevent spurious MMU fault interrupts if something decides to touch
BAR1 after we've unloaded the driver.
Exposed external to BAR so that INSTMEM can use it to better control the
suspend/resume fast-path access.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
If we want to be able to hit the instmem fast-path in a few trickier cases,
we need to be more flexible with when we can initialise BAR2 access.
There's probably a decent case to be made for merging BAR/INSTMEM into BUS,
but that's something to ponder another day.
Flushes have been added after the write to bind the instance block,
as later commits will reveal the need for them.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
RM appears to do this really early in its initialisation, before DEVINIT.
We currently do this before BAR2 initialisation for some reason.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Ben Skeggs