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Merge remote-tracking branch 'remotes/awilliam/tags/vfio-updates-2019…
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…0221.0' into staging

VFIO updates 2019-02-21

 - Workaround kernel overflow bug in vfio type1 DMA unmap
   (Alex Williamson)

 - Refactor vfio container initialization (Eric Auger)

# gpg: Signature made Fri 22 Feb 2019 05:21:07 GMT
# gpg:                using RSA key 239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>" [full]
# gpg:                 aka "Alex Williamson <alex@shazbot.org>" [full]
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>" [full]
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>" [full]
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-updates-20190221.0:
  hw/vfio/common: Refactor container initialization
  vfio/common: Work around kernel overflow bug in DMA unmap

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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@pm215
pm215 committed Feb 22, 2019
2 parents a05838c + 2b6326c commit 8eb29f1
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Showing 2 changed files with 90 additions and 45 deletions.
134 changes: 89 additions & 45 deletions hw/vfio/common.c
View file
Expand Up @@ -220,7 +220,25 @@ static int vfio_dma_unmap(VFIOContainer *container,
.size = size,
};

if (ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
while (ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, &unmap)) {
/*
* The type1 backend has an off-by-one bug in the kernel (71a7d3d78e3c
* v4.15) where an overflow in its wrap-around check prevents us from
* unmapping the last page of the address space. Test for the error
* condition and re-try the unmap excluding the last page. The
* expectation is that we've never mapped the last page anyway and this
* unmap request comes via vIOMMU support which also makes it unlikely
* that this page is used. This bug was introduced well after type1 v2
* support was introduced, so we shouldn't need to test for v1. A fix
* is queued for kernel v5.0 so this workaround can be removed once
* affected kernels are sufficiently deprecated.
*/
if (errno == EINVAL && unmap.size && !(unmap.iova + unmap.size) &&
container->iommu_type == VFIO_TYPE1v2_IOMMU) {
trace_vfio_dma_unmap_overflow_workaround();
unmap.size -= 1ULL << ctz64(container->pgsizes);
continue;
}
error_report("VFIO_UNMAP_DMA: %d", -errno);
return -errno;
}
Expand Down Expand Up @@ -1036,6 +1054,60 @@ static void vfio_put_address_space(VFIOAddressSpace *space)
}
}

/*
* vfio_get_iommu_type - selects the richest iommu_type (v2 first)
*/
static int vfio_get_iommu_type(VFIOContainer *container,
Error **errp)
{
int iommu_types[] = { VFIO_TYPE1v2_IOMMU, VFIO_TYPE1_IOMMU,
VFIO_SPAPR_TCE_v2_IOMMU, VFIO_SPAPR_TCE_IOMMU };
int i;

for (i = 0; i < ARRAY_SIZE(iommu_types); i++) {
if (ioctl(container->fd, VFIO_CHECK_EXTENSION, iommu_types[i])) {
return iommu_types[i];
}
}
error_setg(errp, "No available IOMMU models");
return -EINVAL;
}

static int vfio_init_container(VFIOContainer *container, int group_fd,
Error **errp)
{
int iommu_type, ret;

iommu_type = vfio_get_iommu_type(container, errp);
if (iommu_type < 0) {
return iommu_type;
}

ret = ioctl(group_fd, VFIO_GROUP_SET_CONTAINER, &container->fd);
if (ret) {
error_setg_errno(errp, errno, "Failed to set group container");
return -errno;
}

while (ioctl(container->fd, VFIO_SET_IOMMU, iommu_type)) {
if (iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) {
/*
* On sPAPR, despite the IOMMU subdriver always advertises v1 and
* v2, the running platform may not support v2 and there is no
* way to guess it until an IOMMU group gets added to the container.
* So in case it fails with v2, try v1 as a fallback.
*/
iommu_type = VFIO_SPAPR_TCE_IOMMU;
continue;
}
error_setg_errno(errp, errno, "Failed to set iommu for container");
return -errno;
}

container->iommu_type = iommu_type;
return 0;
}

static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
Error **errp)
{
Expand Down Expand Up @@ -1101,25 +1173,17 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
container->fd = fd;
QLIST_INIT(&container->giommu_list);
QLIST_INIT(&container->hostwin_list);
if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) ||
ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU);
struct vfio_iommu_type1_info info;

ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
if (ret) {
error_setg_errno(errp, errno, "failed to set group container");
ret = -errno;
goto free_container_exit;
}
ret = vfio_init_container(container, group->fd, errp);
if (ret) {
goto free_container_exit;
}

container->iommu_type = v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU;
ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
if (ret) {
error_setg_errno(errp, errno, "failed to set iommu for container");
ret = -errno;
goto free_container_exit;
}
switch (container->iommu_type) {
case VFIO_TYPE1v2_IOMMU:
case VFIO_TYPE1_IOMMU:
{
struct vfio_iommu_type1_info info;

/*
* FIXME: This assumes that a Type1 IOMMU can map any 64-bit
Expand All @@ -1137,30 +1201,13 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
}
vfio_host_win_add(container, 0, (hwaddr)-1, info.iova_pgsizes);
container->pgsizes = info.iova_pgsizes;
} else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) ||
ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) {
break;
}
case VFIO_SPAPR_TCE_v2_IOMMU:
case VFIO_SPAPR_TCE_IOMMU:
{
struct vfio_iommu_spapr_tce_info info;
bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU);

ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
if (ret) {
error_setg_errno(errp, errno, "failed to set group container");
ret = -errno;
goto free_container_exit;
}
container->iommu_type =
v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU;
ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
if (ret) {
container->iommu_type = VFIO_SPAPR_TCE_IOMMU;
v2 = false;
ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
}
if (ret) {
error_setg_errno(errp, errno, "failed to set iommu for container");
ret = -errno;
goto free_container_exit;
}
bool v2 = container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU;

/*
* The host kernel code implementing VFIO_IOMMU_DISABLE is called
Expand Down Expand Up @@ -1222,10 +1269,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
info.dma32_window_size - 1,
0x1000);
}
} else {
error_setg(errp, "No available IOMMU models");
ret = -EINVAL;
goto free_container_exit;
}
}

vfio_kvm_device_add_group(group);
Expand Down
1 change: 1 addition & 0 deletions hw/vfio/trace-events
View file
Expand Up @@ -110,6 +110,7 @@ vfio_region_mmaps_set_enabled(const char *name, bool enabled) "Region %s mmaps e
vfio_region_sparse_mmap_header(const char *name, int index, int nr_areas) "Device %s region %d: %d sparse mmap entries"
vfio_region_sparse_mmap_entry(int i, unsigned long start, unsigned long end) "sparse entry %d [0x%lx - 0x%lx]"
vfio_get_dev_region(const char *name, int index, uint32_t type, uint32_t subtype) "%s index %d, %08x/%0x8"
vfio_dma_unmap_overflow_workaround(void) ""

# hw/vfio/platform.c
vfio_platform_base_device_init(char *name, int groupid) "%s belongs to group #%d"
Expand Down

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