The device could have access to modify them, and it definitely have
access when we implement packed vq. Harden SVQ maintaining a private
copy of the descriptor chain. Other fields like buffer addresses are
already maintained sepparatedly.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20220512175747.142058-2-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Provide an introduction to the main components of a CXL system,
with detailed explanation of memory interleaving, example command
lines and kernel configuration.
This was a challenging document to write due to the need to extract
only that subset of CXL information which is relevant to either
users of QEMU emulation of CXL or to those interested in the
implementation. Much of CXL is concerned with specific elements of
the protocol, management of memory pooling etc which is simply
not relevant to what is currently planned for CXL emulation
in QEMU. All comments welcome
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-43-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add CXL Fixed Memory Windows to the CXL tests.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-40-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tables that differ from normal Q35 tables when running the CXL test.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-39-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The DSDT includes several CXL specific elements and the CEDT
table is only present if we enable CXL.
The test exercises all current functionality with several
CFMWS, CHBS structures in CEDT and ACPI0016/ACPI00017 and _OSC
entries in DSDT.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-38-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add exceptions for the DSDT and the new CEDT tables
specific to a new CXL test in the following patch.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-37-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add the CFMWs memory regions to the memorymap and adjust the
PCI window to avoid hitting the same memory.
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Message-Id: <20220429144110.25167-36-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add a trivial handler for now to cover the root bridge
where we could do some error checking in future.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-35-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
These memops perform interleave decoding, walking down the
CXL topology from CFMWS described host interleave
decoder via CXL host bridge HDM decoders, through the CXL
root ports and finally call CXL type 3 specific read and write
functions.
Note that, whilst functional the current implementation does
not support:
* switches
* multiple HDM decoders at a given level.
* unaligned accesses across the interleave boundaries
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Message-Id: <20220429144110.25167-34-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Once a read or write reaches a CXL type 3 device, the HDM decoders
on the device are used to establish the Device Physical Address
which should be accessed. These functions peform the required maths
and then use a device specific address space to access the
hostmem->mr to fullfil the actual operation. Note that failed writes
are silent, but failed reads return poison. Note this is based
loosely on:
https://lore.kernel.org/qemu-devel/20200817161853.593247-6-f4bug@amsat.org/
[RFC PATCH 0/9] hw/misc: Add support for interleaved memory accesses
Only lightly tested so far. More complex test cases yet to be written.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-33-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Accessor to get hold of the cxl state for a CXL host bridge
without exposing the internals of the implementation.
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-32-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Simple function to search a PCIBus to find a port by
it's port number.
CXL interleave decoding uses the port number as a target
so it is necessary to locate the port when doing interleave
decoding.
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-31-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This adds code to instantiate the slightly extended ACPI root port
description in DSDT as per the CXL 2.0 specification.
Basically a cut and paste job from the i386/pc code.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-30-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The CEDT CXL Fixed Window Memory Window Structures (CFMWs)
define regions of the host phyiscal address map which
(via an impdef means) are configured such that they have
a particular interleave setup across one or more CXL Host Bridges.
Reported-by: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-29-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The concept of these is introduced in [1] in terms of the
description the CEDT ACPI table. The principal is more general.
Unlike once traffic hits the CXL root bridges, the host system
memory address routing is implementation defined and effectively
static once observable by standard / generic system software.
Each CXL Fixed Memory Windows (CFMW) is a region of PA space
which has fixed system dependent routing configured so that
accesses can be routed to the CXL devices below a set of target
root bridges. The accesses may be interleaved across multiple
root bridges.
For QEMU we could have fully specified these regions in terms
of a base PA + size, but as the absolute address does not matter
it is simpler to let individual platforms place the memory regions.
ExampleS:
-cxl-fixed-memory-window targets.0=cxl.0,size=128G
-cxl-fixed-memory-window targets.0=cxl.1,size=128G
-cxl-fixed-memory-window targets.0=cxl0,targets.1=cxl.1,size=256G,interleave-granularity=2k
Specifies
* 2x 128G regions not interleaved across root bridges, one for each of
the root bridges with ids cxl.0 and cxl.1
* 256G region interleaved across root bridges with ids cxl.0 and cxl.1
with a 2k interleave granularity.
When system software enumerates the devices below a given root bridge
it can then decide which CFMW to use. If non interleave is desired
(or possible) it can use the appropriate CFMW for the root bridge in
question. If there are suitable devices to interleave across the
two root bridges then it may use the 3rd CFMS.
A number of other designs were considered but the following constraints
made it hard to adapt existing QEMU approaches to this particular problem.
1) The size must be known before a specific architecture / board brings
up it's PA memory map. We need to set up an appropriate region.
2) Using links to the host bridges provides a clean command line interface
but these links cannot be established until command line devices have
been added.
Hence the two step process used here of first establishing the size,
interleave-ways and granularity + caching the ids of the host bridges
and then, once available finding the actual host bridges so they can
be used later to support interleave decoding.
[1] CXL 2.0 ECN: CEDT CFMWS & QTG DSM (computeexpresslink.org / specifications)
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Acked-by: Markus Armbruster <armbru@redhat.com> # QAPI Schema
Message-Id: <20220429144110.25167-28-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Both registers and the CFMWS entries in CDAT use simple encodings
for the number of interleave ways and the interleave granularity.
Introduce simple conversion functions to/from the unencoded
number / size. So far the iw decode has not been needed so is
it not implemented.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-27-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The CXL Early Discovery Table is defined in the CXL 2.0 specification as
a way for the OS to get CXL specific information from the system
firmware.
CXL 2.0 specification adds an _HID, ACPI0016, for CXL capable host
bridges, with a _CID of PNP0A08 (PCIe host bridge). CXL aware software
is able to use this initiate the proper _OSC method, and get the _UID
which is referenced by the CEDT. Therefore the existence of an ACPI0016
device allows a CXL aware driver perform the necessary actions. For a
CXL capable OS, this works. For a CXL unaware OS, this works.
CEDT awaremess requires more. The motivation for ACPI0017 is to provide
the possibility of having a Linux CXL module that can work on a legacy
Linux kernel. Linux core PCI/ACPI which won't be built as a module,
will see the _CID of PNP0A08 and bind a driver to it. If we later loaded
a driver for ACPI0016, Linux won't be able to bind it to the hardware
because it has already bound the PNP0A08 driver. The ACPI0017 device is
an opportunity to have an object to bind a driver will be used by a
Linux driver to walk the CXL topology and do everything that we would
have preferred to do with ACPI0016.
There is another motivation for an ACPI0017 device which isn't
implemented here. An operating system needs an attach point for a
non-volatile region provider that understands cross-hostbridge
interleaving. Since QEMU emulation doesn't support interleaving yet,
this is more important on the OS side, for now.
As of CXL 2.0 spec, only 1 sub structure is defined, the CXL Host Bridge
Structure (CHBS) which is primarily useful for telling the OS exactly
where the MMIO for the host bridge is.
Link: https://lore.kernel.org/linux-cxl/20210115034911.nkgpzc756d6qmjpl@intel.com/T/#t
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-26-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
CXL host bridges themselves may have MMIO. Since host bridges don't have
a BAR they are treated as special for MMIO. This patch includes
i386/pc support.
Also hook up the device reset now that we have have the MMIO
space in which the results are visible.
Note that we duplicate the PCI express case for the aml_build but
the implementations will diverge when the CXL specific _OSC is
introduced.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-24-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
At this stage we can boot configurations with host bridges,
root ports and type 3 memory devices, so add appropriate
tests.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-23-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Implement get and set handlers for the Label Storage Area
used to hold data describing persistent memory configuration
so that it can be ensured it is seen in the same configuration
after reboot.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-22-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This should introduce no change. Subsequent work will make use of this
new class member.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-21-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
GET_FW_INFO and GET_PARTITION_INFO, for this emulation, is equivalent to
info already returned in the IDENTIFY command. To have a more robust
implementation, add those.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-20-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
A device's volatile and persistent memory are known Host Defined Memory
(HDM) regions. The mechanism by which the device is programmed to claim
the addresses associated with those regions is through dedicated logic
known as the HDM decoder. In order to allow the OS to properly program
the HDMs, the HDM decoders must be modeled.
There are two ways the HDM decoders can be implemented, the legacy
mechanism is through the PCIe DVSEC programming from CXL 1.1 (8.1.3.8),
and MMIO is found in 8.2.5.12 of the spec. For now, 8.1.3.8 is not
implemented.
Much of CXL device logic is implemented in cxl-utils. The HDM decoder
however is implemented directly by the device implementation.
Whilst the implementation currently does no validity checks on the
encoder set up, future work will add sanity checking specific to
the type of cxl component.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-19-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
A CXL memory device (AKA Type 3) is a CXL component that contains some
combination of volatile and persistent memory. It also implements the
previously defined mailbox interface as well as the memory device
firmware interface.
Although the memory device is configured like a normal PCIe device, the
memory traffic is on an entirely separate bus conceptually (using the
same physical wires as PCIe, but different protocol).
Once the CXL topology is fully configure and address decoders committed,
the guest physical address for the memory device is part of a larger
window which is owned by the platform. The creation of these windows
is later in this series.
The following example will create a 256M device in a 512M window:
-object "memory-backend-file,id=cxl-mem1,share,mem-path=cxl-type3,size=512M"
-device "cxl-type3,bus=rp0,memdev=cxl-mem1,id=cxl-pmem0"
Note: Dropped PCDIMM info interfaces for now. They can be added if
appropriate at a later date.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-18-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This adds just enough of a root port implementation to be able to
enumerate root ports (creating the required DVSEC entries). What's not
here yet is the MMIO nor the ability to write some of the DVSEC entries.
This can be added with the qemu commandline by adding a rootport to a
specific CXL host bridge. For example:
-device cxl-rp,id=rp0,bus="cxl.0",addr=0.0,chassis=4
Like the host bridge patch, the ACPI tables aren't generated at this
point and so system software cannot use it.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-17-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Initial test with just pxb-cxl. Other tests will be added
alongside functionality.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-16-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This works like adding a typical pxb device, except the name is
'pxb-cxl' instead of 'pxb-pcie'. An example command line would be as
follows:
-device pxb-cxl,id=cxl.0,bus="pcie.0",bus_nr=1
A CXL PXB is backward compatible with PCIe. What this means in practice
is that an operating system that is unaware of CXL should still be able
to enumerate this topology as if it were PCIe.
One can create multiple CXL PXB host bridges, but a host bridge can only
be connected to the main root bus. Host bridges cannot appear elsewhere
in the topology.
Note that as of this patch, the ACPI tables needed for the host bridge
(specifically, an ACPI object in _SB named ACPI0016 and the CEDT) aren't
created. So while this patch internally creates it, it cannot be
properly used by an operating system or other system software.
Also necessary is to add an exception to scripts/device-crash-test
similar to that for exiting pxb as both must created on a PCIexpress
host bus.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan.Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-15-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
There are going to be some potential overheads to CXL enablement,
for example the host bridge region reserved in memory maps.
Add a machine level control so that CXL is disabled by default.
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-14-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The easiest way to differentiate a CXL bus, and a PCIE bus is using a
flag. A CXL bus, in hardware, is backward compatible with PCIE, and
therefore the code tries pretty hard to keep them in sync as much as
possible.
The other way to implement this would be to try to cast the bus to the
correct type. This is less code and useful for debugging via simply
looking at the flags.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-13-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This opens up the possibility for more types of expanders (other than
PCI and PCIe). We'll need this to create a CXL expander.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-12-Jonathan.Cameron@huawei.com>
CXL specification provides for the ability to obtain logs from the
device. Logs are either spec defined, like the "Command Effects Log"
(CEL), or vendor specific. UUIDs are defined for all log types.
The CEL is a mechanism to provide information to the host about which
commands are supported. It is useful both to determine which spec'd
optional commands are supported, as well as provide a list of vendor
specified commands that might be used. The CEL is already created as
part of mailbox initialization, but here it is now exported to hosts
that use these log commands.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-11-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Errata F4 to CXL 2.0 clarified the meaning of the timer as the
sum of the value set with the timestamp set command and the number
of nano seconds since it was last set.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-10-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Using the previously implemented stubbed helpers, it is now possible to
easily add the missing, required commands to the implementation.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-9-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Memory devices implement extra capabilities on top of CXL devices. This
adds support for that.
A large part of memory devices is the mailbox/command interface. All of
the mailbox handling is done in the mailbox-utils library. Longer term,
new CXL devices that are being emulated may want to handle commands
differently, and therefore would need a mechanism to opt in/out of the
specific generic handlers. As such, this is considered sufficient for
now, but may need more depth in the future.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-8-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This is the beginning of implementing mailbox support for CXL 2.0
devices. The implementation recognizes when the doorbell is rung,
handles the command/payload, clears the doorbell while returning error
codes and data.
Generally the mailbox mechanism is designed to permit communication
between the host OS and the firmware running on the device. For our
purposes, we emulate both the firmware, implemented primarily in
cxl-mailbox-utils.c, and the hardware.
No commands are implemented yet.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-7-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This implements all device MMIO up to the first capability. That
includes the CXL Device Capabilities Array Register, as well as all of
the CXL Device Capability Header Registers. The latter are filled in as
they are implemented in the following patches.
Endianness and alignment are managed by softmmu memory core.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-6-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
A CXL device is a type of CXL component. Conceptually, a CXL device
would be a leaf node in a CXL topology. From an emulation perspective,
CXL devices are the most complex and so the actual implementation is
reserved for discrete commits.
This new device type is specifically catered towards the eventual
implementation of a Type3 CXL.mem device, 8.2.8.5 in the CXL 2.0
specification.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Adam Manzanares <a.manzanares@samsung.com>
Message-Id: <20220429144110.25167-5-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The CXL emulation will be jointly maintained by Ben Widawsky
and Jonathan Cameron. Broken out as a separate patch
to improve visibility.
Signed-off-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220429144110.25167-4-Jonathan.Cameron@huawei.com>
A CXL 2.0 component is any entity in the CXL topology. All components
have a analogous function in PCIe. Except for the CXL host bridge, all
have a PCIe config space that is accessible via the common PCIe
mechanisms. CXL components are enumerated via DVSEC fields in the
extended PCIe header space. CXL components will minimally implement some
subset of CXL.mem and CXL.cache registers defined in 8.2.5 of the CXL
2.0 specification. Two headers and a utility library are introduced to
support the minimum functionality needed to enumerate components.
The cxl_pci header manages bits associated with PCI, specifically the
DVSEC and related fields. The cxl_component.h variant has data
structures and APIs that are useful for drivers implementing any of the
CXL 2.0 components. The library takes care of making use of the DVSEC
bits and the CXL.[mem|cache] registers. Per spec, the registers are
little endian.
None of the mechanisms required to enumerate a CXL capable hostbridge
are introduced at this point.
Note that the CXL.mem and CXL.cache registers used are always 4B wide.
It's possible in the future that this constraint will not hold.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Adam Manzanares <a.manzanares@samsung.com>
Message-Id: <20220429144110.25167-3-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
A CXL component is a hardware entity that implements CXL component
registers from the CXL 2.0 spec (8.2.3). Currently these represent 3
general types.
1. Host Bridge
2. Ports (root, upstream, downstream)
3. Devices (memory, other)
A CXL component can be conceptually thought of as a PCIe device with
extra functionality when enumerated and enabled. For this reason, CXL
does here, and will continue to add on to existing PCI code paths.
Host bridges will typically need to be handled specially and so they can
implement this newly introduced interface or not. All other components
should implement this interface. Implementing this interface allows the
core PCI code to treat these devices as special where appropriate.
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Adam Manzanares <a.manzanares@samsung.com>
Message-Id: <20220429144110.25167-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
error_setg_errno() expects a normal errno value, not a negated
one, so we should use ENOTSUP instead of -ENOSUP.
Fixes: Coverity CID 1487174
Fixes: ("intel_iommu: support snoop control")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220401022824.9337-1-jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Unlike most virtio features ACCESS_PLATFORM is considered mandatory by
QEMU, i.e. the driver must accept it if offered by the device. The
virtio specification says that the driver SHOULD accept the
ACCESS_PLATFORM feature if offered, and that the device MAY fail to
operate if ACCESS_PLATFORM was offered but not negotiated.
While a SHOULD ain't exactly a MUST, we are certainly allowed to fail
the device when the driver fences ACCESS_PLATFORM. With commit
2943b53f68 ("virtio: force VIRTIO_F_IOMMU_PLATFORM") we already made the
decision to do so whenever the get_dma_as() callback is implemented (by
the bus), which in practice means for the entirety of virtio-pci.
That means, if the device needs to translate I/O addresses, then
ACCESS_PLATFORM is mandatory. The aforementioned commit tells us in the
commit message that this is for security reasons. More precisely if we
were to allow a less then trusted driver (e.g. an user-space driver, or
a nested guest) to make the device bypass the IOMMU by not negotiating
ACCESS_PLATFORM, then the guest kernel would have no ability to
control/police (by programming the IOMMU) what pieces of guest memory
the driver may manipulate using the device. Which would break security
assumptions within the guest.
If ACCESS_PLATFORM is offered not because we want the device to utilize
an IOMMU and do address translation, but because the device does not
have access to the entire guest RAM, and needs the driver to grant
access to the bits it needs access to (e.g. confidential guest support),
we still require the guest to have the corresponding logic and to accept
ACCESS_PLATFORM. If the driver does not accept ACCESS_PLATFORM, then
things are bound to go wrong, and we may see failures much less graceful
than failing the device because the driver didn't negotiate
ACCESS_PLATFORM.
So let us make ACCESS_PLATFORM mandatory for the driver regardless
of whether the get_dma_as() callback is implemented or not.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: 2943b53f68 ("virtio: force VIRTIO_F_IOMMU_PLATFORM")
Message-Id: <20220307112939.2780117-1-pasic@linux.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
common.rc has some complicated logic to find the common.config that
dates back to xfstests and is completely unnecessary now. Just include
the contents of the file.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220505094723.732116-1-pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
error_report should generally be followed by a failure; if we can proceed
anyway, that is just a warning and should be communicated properly to
the user with warn_report.
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220511175043.27327-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
According to the NBD spec, a server that advertises
NBD_FLAG_CAN_MULTI_CONN promises that multiple client connections will
not see any cache inconsistencies: when properly separated by a single
flush, actions performed by one client will be visible to another
client, regardless of which client did the flush.
We always satisfy these conditions in qemu - even when we support
multiple clients, ALL clients go through a single point of reference
into the block layer, with no local caching. The effect of one client
is instantly visible to the next client. Even if our backend were a
network device, we argue that any multi-path caching effects that
would cause inconsistencies in back-to-back actions not seeing the
effect of previous actions would be a bug in that backend, and not the
fault of caching in qemu. As such, it is safe to unconditionally
advertise CAN_MULTI_CONN for any qemu NBD server situation that
supports parallel clients.
Note, however, that we don't want to advertise CAN_MULTI_CONN when we
know that a second client cannot connect (for historical reasons,
qemu-nbd defaults to a single connection while nbd-server-add and QMP
commands default to unlimited connections; but we already have
existing means to let either style of NBD server creation alter those
defaults). This is visible by no longer advertising MULTI_CONN for
'qemu-nbd -r' without -e, as in the iotest nbd-qemu-allocation.
The harder part of this patch is setting up an iotest to demonstrate
behavior of multiple NBD clients to a single server. It might be
possible with parallel qemu-io processes, but I found it easier to do
in python with the help of libnbd, and help from Nir and Vladimir in
writing the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Suggested-by: Nir Soffer <nsoffer@redhat.com>
Suggested-by: Vladimir Sementsov-Ogievskiy <v.sementsov-og@mail.ru>
Message-Id: <20220512004924.417153-3-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The next patch wants to adjust whether the NBD server code advertises
MULTI_CONN based on whether it is known if the server limits to
exactly one client. For a server started by QMP, this information is
obtained through nbd_server_start (which can support more than one
export); but for qemu-nbd (which supports exactly one export), it is
controlled only by the command-line option -e/--shared. Since we
already have a hook function used by qemu-nbd, it's easiest to just
alter its signature to fit our needs.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20220512004924.417153-2-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
