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vfio/spapr: Create DMA window dynamically (SPAPR IOMMU v2)

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New VFIO_SPAPR_TCE_v2_IOMMU type supports dynamic DMA window management.
This adds ability to VFIO common code to dynamically allocate/remove
DMA windows in the host kernel when new VFIO container is added/removed.

This adds a helper to vfio_listener_region_add which makes
VFIO_IOMMU_SPAPR_TCE_CREATE ioctl and adds just created IOMMU into
the host IOMMU list; the opposite action is taken in
vfio_listener_region_del.

When creating a new window, this uses heuristic to decide on the TCE table
levels number.

This should cause no guest visible change in behavior.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
[dwg: Added some casts to prevent printf() warnings on certain targets
 where the kernel headers' __u64 doesn't match uint64_t or PRIx64]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Alexey Kardashevskiy 2016-07-04 13:33:06 +10:00 committed by David Gibson
parent f4ec5e26ed
commit 2e4109de8e
4 changed files with 149 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
hw/vfio/common.c
View File

@ -265,6 +265,21 @@ static void vfio_host_win_add(VFIOContainer *container,
QLIST_INSERT_HEAD(&container->hostwin_list, hostwin, hostwin_next);
}
static int vfio_host_win_del(VFIOContainer *container, hwaddr min_iova,
hwaddr max_iova)
{
VFIOHostDMAWindow *hostwin;
QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
if (hostwin->min_iova == min_iova && hostwin->max_iova == max_iova) {
QLIST_REMOVE(hostwin, hostwin_next);
return 0;
}
}
return -1;
}
static bool vfio_listener_skipped_section(MemoryRegionSection *section)
{
return (!memory_region_is_ram(section->mr) &&
@ -380,6 +395,31 @@ static void vfio_listener_region_add(MemoryListener *listener,
}
end = int128_get64(int128_sub(llend, int128_one()));
if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
VFIOHostDMAWindow *hostwin;
hwaddr pgsize = 0;
/* For now intersections are not allowed, we may relax this later */
QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
if (ranges_overlap(hostwin->min_iova,
hostwin->max_iova - hostwin->min_iova + 1,
section->offset_within_address_space,
int128_get64(section->size))) {
ret = -1;
goto fail;
}
}
ret = vfio_spapr_create_window(container, section, &pgsize);
if (ret) {
goto fail;
}
vfio_host_win_add(container, section->offset_within_address_space,
section->offset_within_address_space +
int128_get64(section->size) - 1, pgsize);
}
hostwin_found = false;
QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
@ -523,6 +563,18 @@ static void vfio_listener_region_del(MemoryListener *listener,
"0x%"HWADDR_PRIx") = %d (%m)",
container, iova, int128_get64(llsize), ret);
}
if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
vfio_spapr_remove_window(container,
section->offset_within_address_space);
if (vfio_host_win_del(container,
section->offset_within_address_space,
section->offset_within_address_space +
int128_get64(section->size) - 1) < 0) {
hw_error("%s: Cannot delete missing window at %"HWADDR_PRIx,
__func__, section->offset_within_address_space);
}
}
}
static const MemoryListener vfio_memory_listener = {
@ -961,11 +1013,6 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
}
}
/*
* This only considers the host IOMMU's 32-bit window. At
* some point we need to add support for the optional 64-bit
* window and dynamic windows
*/
info.argsz = sizeof(info);
ret = ioctl(fd, VFIO_IOMMU_SPAPR_TCE_GET_INFO, &info);
if (ret) {
@ -977,11 +1024,24 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as)
goto free_container_exit;
}
/* The default table uses 4K pages */
vfio_host_win_add(container, info.dma32_window_start,
info.dma32_window_start +
info.dma32_window_size - 1,
0x1000);
if (v2) {
/*
* There is a default window in just created container.
* To make region_add/del simpler, we better remove this
* window now and let those iommu_listener callbacks
* create/remove them when needed.
*/
ret = vfio_spapr_remove_window(container, info.dma32_window_start);
if (ret) {
goto free_container_exit;
}
} else {
/* The default table uses 4K pages */
vfio_host_win_add(container, info.dma32_window_start,
info.dma32_window_start +
info.dma32_window_size - 1,
0x1000);
}
} else {
error_report("vfio: No available IOMMU models");
ret = -EINVAL;

71
hw/vfio/spapr.c
View File

@ -137,3 +137,74 @@ const MemoryListener vfio_prereg_listener = {
.region_add = vfio_prereg_listener_region_add,
.region_del = vfio_prereg_listener_region_del,
};
int vfio_spapr_create_window(VFIOContainer *container,
MemoryRegionSection *section,
hwaddr *pgsize)
{
int ret;
unsigned pagesize = memory_region_iommu_get_min_page_size(section->mr);
unsigned entries, pages;
struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
/*
* FIXME: For VFIO iommu types which have KVM acceleration to
* avoid bouncing all map/unmaps through qemu this way, this
* would be the right place to wire that up (tell the KVM
* device emulation the VFIO iommu handles to use).
*/
create.window_size = int128_get64(section->size);
create.page_shift = ctz64(pagesize);
/*
* SPAPR host supports multilevel TCE tables, there is some
* heuristic to decide how many levels we want for our table:
* 0..64 = 1; 65..4096 = 2; 4097..262144 = 3; 262145.. = 4
*/
entries = create.window_size >> create.page_shift;
pages = MAX((entries * sizeof(uint64_t)) / getpagesize(), 1);
pages = MAX(pow2ceil(pages) - 1, 1); /* Round up */
create.levels = ctz64(pages) / 6 + 1;
ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
if (ret) {
error_report("Failed to create a window, ret = %d (%m)", ret);
return -errno;
}
if (create.start_addr != section->offset_within_address_space) {
vfio_spapr_remove_window(container, create.start_addr);
error_report("Host doesn't support DMA window at %"HWADDR_PRIx", must be %"PRIx64,
section->offset_within_address_space,
(uint64_t)create.start_addr);
ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
return -EINVAL;
}
trace_vfio_spapr_create_window(create.page_shift,
create.window_size,
create.start_addr);
*pgsize = pagesize;
return 0;
}
int vfio_spapr_remove_window(VFIOContainer *container,
hwaddr offset_within_address_space)
{
struct vfio_iommu_spapr_tce_remove remove = {
.argsz = sizeof(remove),
.start_addr = offset_within_address_space,
};
int ret;
ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove);
if (ret) {
error_report("Failed to remove window at %"PRIx64,
(uint64_t)remove.start_addr);
return -errno;
}
trace_vfio_spapr_remove_window(offset_within_address_space);
return 0;
}

2
hw/vfio/trace-events
View File

@ -121,3 +121,5 @@ vfio_prereg_listener_region_add_skip(uint64_t start, uint64_t end) "%"PRIx64" -
vfio_prereg_listener_region_del_skip(uint64_t start, uint64_t end) "%"PRIx64" - %"PRIx64
vfio_prereg_register(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d"
vfio_prereg_unregister(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d"
vfio_spapr_create_window(int ps, uint64_t ws, uint64_t off) "pageshift=0x%x winsize=0x%"PRIx64" offset=0x%"PRIx64
vfio_spapr_remove_window(uint64_t off) "offset=%"PRIx64

6
include/hw/vfio/vfio-common.h
View File

@ -168,4 +168,10 @@ int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type,
#endif
extern const MemoryListener vfio_prereg_listener;
int vfio_spapr_create_window(VFIOContainer *container,
MemoryRegionSection *section,
hwaddr *pgsize);
int vfio_spapr_remove_window(VFIOContainer *container,
hwaddr offset_within_address_space);
#endif /* !HW_VFIO_VFIO_COMMON_H */