The emulated devices can run simultaneously with the guest, so
we need to be careful with ordering of load and stores done by
them to the guest system memory, which need to be observed in
the right order by the guest operating system.
This adds a barrier call to the basic DMA read/write ops which
is currently implemented as a smp_mb(), but could be later
improved for more fine grained control of barriers.
Additionally, a _relaxed() variant of the accessors is provided
to easily convert devices who would be performance sensitive
and negatively impacted by the change.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This patch adds the basic infrastructure necessary to emulate an IOMMU
visible to the guest. The DMAContext structure is extended with
information and a callback describing the translation, and the various
DMA functions used by devices will now perform IOMMU translation using
this callback.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
dma-helpers.c contains a number of helper functions for doing
scatter/gather DMA, and various block device related DMA. Currently,
these directly access guest memory using cpu_physical_memory_*(),
assuming no IOMMU translation.
This patch updates this code to use the new universal DMA helper
functions. qemu_sglist_init() now takes a DMAContext * to describe
the DMA address space in which the scatter/gather will take place.
We minimally update the callers qemu_sglist_init() to pass NULL
(i.e. no translation, same as current behaviour). Some of those
callers should pass something else in some cases to allow proper IOMMU
translation in future, but that will be fixed in later patches.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Not that long ago, every device implementation using DMA directly
accessed guest memory using cpu_physical_memory_*(). This meant that
adding support for a guest visible IOMMU would require changing every
one of these devices to go through IOMMU translation.
Shortly before qemu 1.0, I made a start on fixing this by providing
helper functions for PCI DMA. These are currently just stubs which
call the direct access functions, but mean that an IOMMU can be
implemented in one place, rather than for every PCI device.
Clearly, this doesn't help for non PCI devices, which could also be
IOMMU translated on some platforms. It is also problematic for the
devices which have both PCI and non-PCI version (e.g. OHCI, AHCI) - we
cannot use the the pci_dma_*() functions, because they assume the
presence of a PCIDevice, but we don't want to have to check between
pci_dma_*() and cpu_physical_memory_*() every time we do a DMA in the
device code.
This patch makes the first step on addressing both these problems, by
introducing new (stub) dma helper functions which can be used for any
DMA capable device.
These dma functions take a DMAContext *, a new (currently empty)
variable describing the DMA address space in which the operation is to
take place. NULL indicates untranslated DMA directly into guest
physical address space. The intention is that in future non-NULL
values will given information about any necessary IOMMU translation.
DMA using devices must obtain a DMAContext (or, potentially, contexts)
from their bus or platform. For now this patch just converts the PCI
wrappers to be implemented in terms of the universal wrappers,
converting other drivers can take place over time.
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
A while back, we introduced the dma_addr_t type, which is supposed to
be used for bus visible memory addresses. At present, this is an
alias for target_phys_addr_t, but this will change when we eventually
add support for guest visible IOMMUs.
There are some instances of target_phys_addr_t in the code now which
should really be dma_addr_t, but can't be trivially converted due to
missing features which this patch corrects.
* We add DMA_ADDR_BITS analagous to TARGET_PHYS_ADDR_BITS. This is
important where we need to make a compile-time (#if) based on the
size of dma_addr_t.
* We add a new helper macro to create device properties which take a
dma_addr_t, currently an alias to DEFINE_PROP_TADDR().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
* kwolf/for-anthony: (46 commits)
qed: remove incoming live migration blocker
qed: honor BDRV_O_INCOMING for incoming live migration
migration: clear BDRV_O_INCOMING flags on end of incoming live migration
qed: add bdrv_invalidate_cache to be called after incoming live migration
blockdev: open images with BDRV_O_INCOMING on incoming live migration
block: add a function to clear incoming live migration flags
block: Add new BDRV_O_INCOMING flag to notice incoming live migration
block stream: close unused files and update ->backing_hd
qemu-iotests: Fix call syntax for qemu-io
qemu-iotests: Fix call syntax for qemu-img
qemu-iotests: Test unknown qcow2 header extensions
qemu-iotests: qcow2.py
sheepdog: fix send req helpers
sheepdog: implement SD_OP_FLUSH_VDI operation
block: bdrv_append() fixes
qed: track dirty flag status
qemu-img: add dirty flag status
qed: image fragmentation statistics
qemu-img: add image fragmentation statistics
block: document job API
...
This comment is useless, just removes it and makes the codes clear.
Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Currently dma_bdrv_io() takes a 'to_dev' boolean parameter to
determine the direction of DMA it is emulating. We already have a
DMADirection enum designed specifically to encode DMA directions.
This patch uses it for dma_bdrv_io() as well. This involves removing
the DMADirection definition from the #ifdef it was inside, but since that
only existed to protect the definition of dma_addr_t from places where
config.h is not included, there wasn't any reason for it to be there in
the first place.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
These helpers do a full transfer from an in-memory buffer to target
memory, with support for scatter/gather lists. It will be used to
store the reply of an emulated command into a QEMUSGList provided by
the adapter.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
scsi-disk will manage scatter/gather list, but it does not create
single entries so it remains target-independent. Make QEMUSGList
available to it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch uses the newly created dma_addr_t type throughout the
scatter/gather handling code in dma-helpers.c whenever we need to
represent a dma bus address. This makes a better distinction as to
what is a bus address and what is a cpu physical address. Since we
don't support IOMMUs yet, they can't be very different for now, but
that will change in future, and this preliminary helps clarify what's
going on.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
As a preliminary to adding more extensive DMA and IOMMU infrastructure
support into qemu, this patch defines a dma_addr_t for storing DMA bus
addresses and a DMADirection enum which describes whether a DMA is
from an external device to main memory or from main memory to an
external device.
For now dma_addr_t is just defined to be target_phys_addr_t, but in
future, we can change this to support machines where we have bus
addresses which don't necessarily have the same format as CPU physical
addresses.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Target-independent code cannot construct sglists, but it can take
them from the outside as a black box. Allow this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Move the QEMUSGList typedef to qemu-common so it can easily be used.
The actual struct definition stays in dma.h.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Make dma_bdrv_io available for drivers, and pass an explicit I/O function
instead of hardcoding bdrv_aio_readv/bdrv_aio_writev. This is required
to implement non-READ/WRITE dma commands in the ide driver, e.g. the
upcoming TRIM support.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In the very least, a change like this requires discussion on the list.
The naming convention is goofy and it causes a massive merge problem. Something
like this _must_ be presented on the list first so people can provide input
and cope with it.
This reverts commit 99a0949b72.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Now that we have a separate aio pool structure we can remove those
aio pool details from BlockDriver.
Every driver supporting AIO now needs to declare a static AIOPool
with the aiocb size and the cancellation method. This cleans up the
current code considerably and will make it cleaner and more obvious
to support two different aio implementations behind a single
BlockDriver.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The only target dependency for most hardware is sizeof(target_phys_addr_t).
Build these files into a convenience library, and use that instead of
building for every target.
Remove and poison various target specific macros to avoid bogus target
dependencies creeping back in.
Big/Little endian is not handled because devices should not know or care
about this to start with.
Signed-off-by: Paul Brook <paul@codesourcery.com>
Move the dma helpers to a private aio pool, and implement a cancellation
method for them. Should prevent issues when cancelling I/O while dma is
in progress.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6872 c046a42c-6fe2-441c-8c8c-71466251a162
These helpers perform read/write requests on entire scatter/gather lists,
relieving the device emulation code from mapping and unmapping physical
memory, and from looping when map resources are exhausted.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6524 c046a42c-6fe2-441c-8c8c-71466251a162
Scatter-gather lists are used extensively in dma-capable devices; a
single data structure allows more code reuse later on.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6522 c046a42c-6fe2-441c-8c8c-71466251a162
