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Re: [Qemu-devel] [RFC] virtio: convert to use DMA api
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From: |
Jason Wang |
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Subject: |
Re: [Qemu-devel] [RFC] virtio: convert to use DMA api |
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Date: |
Tue, 24 Nov 2015 13:38:54 +0800 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 11/23/2015 04:06 PM, Michael S. Tsirkin wrote:
> On Mon, Nov 23, 2015 at 03:41:11PM +0800, Jason Wang wrote:
>> Currently, all virtio devices bypass IOMMU completely. This is because
>> address_space_memory is assumed and used during DMA emulation. This
>> patch converts the virtio core API to use DMA API. This idea is
>>
>> - introducing a new transport specific helper to query the dma address
>> space. (only pci version is implemented).
>> - query and use this address space during virtio device guest memory
>> accessing
>>
>> With this virtiodevices will not bypass IOMMU anymore. Little tested with
>> intel_iommu=on with virtio guest DMA series posted in
>> https://lkml.org/lkml/2015/10/28/64.
>>
>> TODO:
>> - Feature bit for this
> This probably implies it should only be implemented
> if device supports the modern mode.
> Not sure what's the best way to handle transitional
> devices.
Don't see the issue here. Transitional devices could decide based on the
feature bit?
, for the name, how about something like VIRTIO_F_HOST_IOMMU ?
>
>> - Implement this for all transports
> Tested with vhost, and it does not seem to work.
> So more TODO:
> - make this work with vhost-user and vhost-net.
>
> Also, it seems prudent to add
> - make the new behaviour conditional on a new property
Right.
>
>> Signed-off-by: Jason Wang <address@hidden>
>> ---
>> hw/block/virtio-blk.c | 2 +-
>> hw/char/virtio-serial-bus.c | 2 +-
>> hw/scsi/virtio-scsi.c | 2 +-
>> hw/virtio/virtio-pci.c | 9 +++++++++
>> hw/virtio/virtio.c | 36 +++++++++++++++++++--------------
>> include/hw/virtio/virtio-access.h | 42
>> +++++++++++++++++++++++++++++----------
>> include/hw/virtio/virtio-bus.h | 1 +
>> include/hw/virtio/virtio.h | 2 +-
>> 8 files changed, 67 insertions(+), 29 deletions(-)
>>
>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>> index e70fccf..5499480 100644
>> --- a/hw/block/virtio-blk.c
>> +++ b/hw/block/virtio-blk.c
>> @@ -846,7 +846,7 @@ static int virtio_blk_load_device(VirtIODevice *vdev,
>> QEMUFile *f,
>> req->next = s->rq;
>> s->rq = req;
>>
>> - virtqueue_map(&req->elem);
>> + virtqueue_map(vdev, &req->elem);
>> }
>>
>> return 0;
>> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
>> index 497b0af..39e9ed2 100644
>> --- a/hw/char/virtio-serial-bus.c
>> +++ b/hw/char/virtio-serial-bus.c
>> @@ -705,7 +705,7 @@ static int fetch_active_ports_list(QEMUFile *f, int
>> version_id,
>>
>> qemu_get_buffer(f, (unsigned char *)&port->elem,
>> sizeof(port->elem));
>> - virtqueue_map(&port->elem);
>> + virtqueue_map(&s->parent_obj, &port->elem);
>>
>> /*
>> * Port was throttled on source machine. Let's
>> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
>> index 7655401..0734d27 100644
>> --- a/hw/scsi/virtio-scsi.c
>> +++ b/hw/scsi/virtio-scsi.c
>> @@ -206,7 +206,7 @@ static void *virtio_scsi_load_request(QEMUFile *f,
>> SCSIRequest *sreq)
>> req = virtio_scsi_init_req(s, vs->cmd_vqs[n]);
>> qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));
>>
>> - virtqueue_map(&req->elem);
>> + virtqueue_map(&vs->parent_obj, &req->elem);
>>
>> if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size,
>> sizeof(VirtIOSCSICmdResp) + vs->sense_size) <
>> 0) {
>> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
>> index dd48562..876505d 100644
>> --- a/hw/virtio/virtio-pci.c
>> +++ b/hw/virtio/virtio-pci.c
>> @@ -1211,6 +1211,14 @@ static int virtio_pci_query_nvectors(DeviceState *d)
>> return proxy->nvectors;
>> }
>>
>> +static AddressSpace *virtio_pci_get_dma_as(DeviceState *d)
>> +{
>> + VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
>> + PCIDevice *dev = &proxy->pci_dev;
>> +
>> + return pci_get_address_space(dev);
>> +}
>> +
>> static int virtio_pci_add_mem_cap(VirtIOPCIProxy *proxy,
>> struct virtio_pci_cap *cap)
>> {
>> @@ -2476,6 +2484,7 @@ static void virtio_pci_bus_class_init(ObjectClass
>> *klass, void *data)
>> k->device_plugged = virtio_pci_device_plugged;
>> k->device_unplugged = virtio_pci_device_unplugged;
>> k->query_nvectors = virtio_pci_query_nvectors;
>> + k->get_dma_as = virtio_pci_get_dma_as;
>> }
>>
>> static const TypeInfo virtio_pci_bus_info = {
>> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
>> index 1edef59..e09430d 100644
>> --- a/hw/virtio/virtio.c
>> +++ b/hw/virtio/virtio.c
>> @@ -21,6 +21,7 @@
>> #include "hw/virtio/virtio-bus.h"
>> #include "migration/migration.h"
>> #include "hw/virtio/virtio-access.h"
>> +#include "sysemu/dma.h"
>>
>> /*
>> * The alignment to use between consumer and producer parts of vring.
>> @@ -247,6 +248,7 @@ int virtio_queue_empty(VirtQueue *vq)
>> static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
>> unsigned int len)
>> {
>> + AddressSpace *dma_as = virtio_get_dma_as(vq->vdev);
>> unsigned int offset;
>> int i;
>>
>> @@ -254,17 +256,17 @@ static void virtqueue_unmap_sg(VirtQueue *vq, const
>> VirtQueueElement *elem,
>> for (i = 0; i < elem->in_num; i++) {
>> size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
>>
>> - cpu_physical_memory_unmap(elem->in_sg[i].iov_base,
>> - elem->in_sg[i].iov_len,
>> - 1, size);
>> + dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
>> elem->in_sg[i].iov_len,
>> + DMA_DIRECTION_FROM_DEVICE, size);
>>
>> offset += size;
>> }
>>
>> for (i = 0; i < elem->out_num; i++)
>> - cpu_physical_memory_unmap(elem->out_sg[i].iov_base,
>> - elem->out_sg[i].iov_len,
>> - 0, elem->out_sg[i].iov_len);
>> + dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
>> + elem->out_sg[i].iov_len,
>> + DMA_DIRECTION_TO_DEVICE,
>> + elem->out_sg[i].iov_len);
>> }
>>
>> void virtqueue_discard(VirtQueue *vq, const VirtQueueElement *elem,
>> @@ -448,9 +450,9 @@ int virtqueue_avail_bytes(VirtQueue *vq, unsigned int
>> in_bytes,
>> return in_bytes <= in_total && out_bytes <= out_total;
>> }
>>
>> -static void virtqueue_map_iovec(struct iovec *sg, hwaddr *addr,
>> - unsigned int *num_sg, unsigned int max_size,
>> - int is_write)
>> +static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
>> + hwaddr *addr, unsigned int *num_sg,
>> + unsigned int max_size, int is_write)
>> {
>> unsigned int i;
>> hwaddr len;
>> @@ -469,7 +471,10 @@ static void virtqueue_map_iovec(struct iovec *sg,
>> hwaddr *addr,
>>
>> for (i = 0; i < *num_sg; i++) {
>> len = sg[i].iov_len;
>> - sg[i].iov_base = cpu_physical_memory_map(addr[i], &len, is_write);
>> + sg[i].iov_base = dma_memory_map(virtio_get_dma_as(vdev),
>> + addr[i], &len, is_write ?
>> + DMA_DIRECTION_FROM_DEVICE :
>> + DMA_DIRECTION_TO_DEVICE);
>> if (!sg[i].iov_base) {
>> error_report("virtio: error trying to map MMIO memory");
>> exit(1);
>> @@ -491,13 +496,14 @@ static void virtqueue_map_iovec(struct iovec *sg,
>> hwaddr *addr,
>> }
>> }
>>
>> -void virtqueue_map(VirtQueueElement *elem)
>> +void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
>> {
>> - virtqueue_map_iovec(elem->in_sg, elem->in_addr, &elem->in_num,
>> + virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num,
>> MIN(ARRAY_SIZE(elem->in_sg),
>> ARRAY_SIZE(elem->in_addr)),
>> 1);
>> - virtqueue_map_iovec(elem->out_sg, elem->out_addr, &elem->out_num,
>> - MIN(ARRAY_SIZE(elem->out_sg),
>> ARRAY_SIZE(elem->out_addr)),
>> + virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num,
>> + MIN(ARRAY_SIZE(elem->out_sg),
>> + ARRAY_SIZE(elem->out_addr)),
>> 0);
>> }
>>
>> @@ -562,7 +568,7 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
>> } while ((i = virtqueue_next_desc(vdev, desc_pa, i, max)) != max);
>>
>> /* Now map what we have collected */
>> - virtqueue_map(elem);
>> + virtqueue_map(vdev, elem);
>>
>> elem->index = head;
>>
>> diff --git a/include/hw/virtio/virtio-access.h
>> b/include/hw/virtio/virtio-access.h
>> index 8aec843..cca7d2a 100644
>> --- a/include/hw/virtio/virtio-access.h
>> +++ b/include/hw/virtio/virtio-access.h
>> @@ -15,8 +15,20 @@
>> #ifndef _QEMU_VIRTIO_ACCESS_H
>> #define _QEMU_VIRTIO_ACCESS_H
>> #include "hw/virtio/virtio.h"
>> +#include "hw/virtio/virtio-bus.h"
>> #include "exec/address-spaces.h"
>>
>> +static inline AddressSpace *virtio_get_dma_as(VirtIODevice *vdev)
>> +{
>> + BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
>> + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
>> +
>> + if (k->get_dma_as) {
>> + return k->get_dma_as(qbus->parent);
>> + }
>> + return &address_space_memory;
>> +}
>> +
>> static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
>> {
>> if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
>> @@ -47,45 +59,55 @@ static inline bool
>> virtio_legacy_is_cross_endian(VirtIODevice *vdev)
>>
>> static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa)
>> {
>> + AddressSpace *dma_as = virtio_get_dma_as(vdev);
>> +
>> if (virtio_access_is_big_endian(vdev)) {
>> - return lduw_be_phys(&address_space_memory, pa);
>> + return lduw_be_phys(dma_as, pa);
>> }
>> - return lduw_le_phys(&address_space_memory, pa);
>> + return lduw_le_phys(dma_as, pa);
>> }
>>
>> static inline uint32_t virtio_ldl_phys(VirtIODevice *vdev, hwaddr pa)
>> {
>> + AddressSpace *dma_as = virtio_get_dma_as(vdev);
>> +
>> if (virtio_access_is_big_endian(vdev)) {
>> - return ldl_be_phys(&address_space_memory, pa);
>> + return ldl_be_phys(dma_as, pa);
>> }
>> - return ldl_le_phys(&address_space_memory, pa);
>> + return ldl_le_phys(dma_as, pa);
>> }
>>
>> static inline uint64_t virtio_ldq_phys(VirtIODevice *vdev, hwaddr pa)
>> {
>> + AddressSpace *dma_as = virtio_get_dma_as(vdev);
>> +
>> if (virtio_access_is_big_endian(vdev)) {
>> - return ldq_be_phys(&address_space_memory, pa);
>> + return ldq_be_phys(dma_as, pa);
>> }
>> - return ldq_le_phys(&address_space_memory, pa);
>> + return ldq_le_phys(dma_as, pa);
>> }
>>
>> static inline void virtio_stw_phys(VirtIODevice *vdev, hwaddr pa,
>> uint16_t value)
>> {
>> + AddressSpace *dma_as = virtio_get_dma_as(vdev);
>> +
>> if (virtio_access_is_big_endian(vdev)) {
>> - stw_be_phys(&address_space_memory, pa, value);
>> + stw_be_phys(dma_as, pa, value);
>> } else {
>> - stw_le_phys(&address_space_memory, pa, value);
>> + stw_le_phys(dma_as, pa, value);
>> }
>> }
>>
>> static inline void virtio_stl_phys(VirtIODevice *vdev, hwaddr pa,
>> uint32_t value)
>> {
>> + AddressSpace *dma_as = virtio_get_dma_as(vdev);
>> +
>> if (virtio_access_is_big_endian(vdev)) {
>> - stl_be_phys(&address_space_memory, pa, value);
>> + stl_be_phys(dma_as, pa, value);
>> } else {
>> - stl_le_phys(&address_space_memory, pa, value);
>> + stl_le_phys(dma_as, pa, value);
>> }
>> }
>>
>> diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
>> index 6c3d4cb..638735e 100644
>> --- a/include/hw/virtio/virtio-bus.h
>> +++ b/include/hw/virtio/virtio-bus.h
>> @@ -71,6 +71,7 @@ typedef struct VirtioBusClass {
>> * Note that changing this will break migration for this transport.
>> */
>> bool has_variable_vring_alignment;
>> + AddressSpace *(*get_dma_as)(DeviceState *d);
>> } VirtioBusClass;
>>
>> struct VirtioBusState {
>> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
>> index 205fadf..7a8ef13 100644
>> --- a/include/hw/virtio/virtio.h
>> +++ b/include/hw/virtio/virtio.h
>> @@ -151,7 +151,7 @@ void virtqueue_discard(VirtQueue *vq, const
>> VirtQueueElement *elem,
>> void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
>> unsigned int len, unsigned int idx);
>>
>> -void virtqueue_map(VirtQueueElement *elem);
>> +void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem);
>> int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem);
>> int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
>> unsigned int out_bytes);
>> --
>> 2.5.0