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2012-06-27Add a memory barrier to DMA functionsBenjamin Herrenschmidt1-0/+2
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>
2012-06-27iommu: Introduce IOMMU emulation infrastructureDavid Gibson1-1/+171
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>
2012-06-27iommu: Make sglists and dma_bdrv helpers use new universal DMA helpersDavid Gibson1-12/+12
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>
2012-06-27iommu: Add universal DMA helper functionsDavid Gibson1-0/+16
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>
2012-04-05Use DMADirection type for dma_bdrv_ioDavid Gibson1-8/+12
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>
2012-04-05aio: move BlockDriverAIOCB to qemu-aio.hPaolo Bonzini1-1/+0
And remove several block_int.h inclusions that should not be there. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-22dma-helpers: add accounting wrappersPaolo Bonzini1-0/+6
The length of the transfer is already in the sglist, the wrapper simply fetches it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-02-22dma-helpers: add dma_buf_read and dma_buf_writePaolo Bonzini1-0/+31
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>
2011-12-15dma: the passed io_func does not return NULLPaolo Bonzini1-3/+1
Initially found with the following semantic patch: @ type @ BlockDriverAIOCB *x; expression E; @@ x = E; - if (x == NULL) { ... } @ acb1 @ expression E, E1; @@ E1->acb = E; - if (E1->acb == NULL) { ... } @ aiocb1 @ expression E, E1; @@ E1->aiocb = E; - if (E1->aiocb == NULL) { ... } @ acb @ expression E, E1; @@ E1.acb = E; - if (E1.acb == NULL) { ... } @ aiocb @ expression E, E1; @@ E1.aiocb = E; - if (E1.aiocb == NULL) { ... } but changed manually to include an assert. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05dma-helpers: Add trace eventsKevin Wolf1-0/+10
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-11-01Use dma_addr_t type for scatter/gather codeDavid Gibson1-3/+2
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>
2011-09-20dma-helpers: rewrite completion/cancellationPaolo Bonzini1-13/+31
This fixes various problems with completion/cancellation: * if the io_func fails to get an AIOCB, the callback wasn't called * If DMA encounters a bounce buffer conflict, and the DMA operation is canceled before the bottom half fires, bad things happen. * memory is not unmapped after cancellation, again causing problems when doing DMA to I/O areas * cancellation could leak the iovec * the callback was missed if the I/O operation failed without returning an AIOCB and probably more that I've missed. The patch fixes them by sharing the cleanup code between completion and cancellation. The dma_bdrv_cb now returns a boolean completed/not completed flag, and the wrapper dma_continue takes care of tasks to do upon completion. Most of these are basically impossible in practice, but it is better to be tidy... Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-09-19dma-helpers: rename is_write to to_devPaolo Bonzini1-7/+7
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-20Use glib memory allocation and free functionsAnthony Liguori1-3/+3
qemu_malloc/qemu_free no longer exist after this commit. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-06-15make dma_bdrv_io available to driversChristoph Hellwig1-13/+10
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>
2009-10-01Revert "Get rid of _t suffix"Anthony Liguori1-4/+4
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 99a0949b720a0936da2052cb9a46db04ffc6db29. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-10-01Get rid of _t suffixmalc1-4/+4
Some not so obvious bits, slirp and Xen were left alone for the time being. Signed-off-by: malc <av1474@comtv.ru>
2009-05-27fully split aio_pool from BlockDriverChristoph Hellwig1-17/+15
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>
2009-04-07Fix a few Sparse warningsblueswir11-1/+1
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7016 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-28Fix DMA API when handling an immediate error from block layer (Avi Kivity)aliguori1-6/+21
The block layer may signal an immediate error on an asynchronous request by returning NULL. The DMA API did not handle this correctly, returning an AIO request which would never complete (and which would crash if cancelled). Fix by detecting the failure and propagating it. 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@6893 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-20Move block dma helpers aiocb to store dma state (Avi Kivity)aliguori1-17/+20
Use the dedicated dma aiocb to store intermediate state for dma block transactions. 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@6874 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-20Implement cancellation method for dma async I/O (Avi Kivity)aliguori1-1/+14
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
2009-02-05Introduce block dma helpers (Avi Kivity)aliguori1-1/+118
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
2009-02-05Add a scatter-gather list type and accessors (Avi Kivity)aliguori1-0/+38
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
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