This series is the start of adding full DMABUF support to
iommufd. Currently it is limited to only work with VFIO's DMABUF exporter.
It sits on top of Leon's series to add a DMABUF exporter to VFIO:
https://lore.kernel.org/all/20251120-dmabuf-vfio-v9-0-d7f71607f371@nvidia.c…
The existing IOMMU_IOAS_MAP_FILE is enhanced to detect DMABUF fd's, but
otherwise works the same as it does today for a memfd. The user can select
a slice of the FD to map into the ioas and if the underliyng alignment
requirements are met it will be placed in the iommu_domain.
Though limited, it is enough to allow a VMM like QEMU to connect MMIO BAR
memory from VFIO to an iommu_domain controlled by iommufd. This is used
for PCI Peer to Peer support in VMs, and is the last feature that the VFIO
type 1 container has that iommufd couldn't do.
The VFIO type1 version extracts raw PFNs from VMAs, which has no lifetime
control and is a use-after-free security problem.
Instead iommufd relies on revokable DMABUFs. Whenever VFIO thinks there
should be no access to the MMIO it can shoot down the mapping in iommufd
which will unmap it from the iommu_domain. There is no automatic remap,
this is a safety protocol so the kernel doesn't get stuck. Userspace is
expected to know it is doing something that will revoke the dmabuf and
map/unmap it around the activity. Eg when QEMU goes to issue FLR it should
do the map/unmap to iommufd.
Since DMABUF is missing some key general features for this use case it
relies on a "private interconnect" between VFIO and iommufd via the
vfio_pci_dma_buf_iommufd_map() call.
The call confirms the DMABUF has revoke semantics and delivers a phys_addr
for the memory suitable for use with iommu_map().
Medium term there is a desire to expand the supported DMABUFs to include
GPU drivers to support DPDK/SPDK type use cases so future series will work
to add a general concept of revoke and a general negotiation of
interconnect to remove vfio_pci_dma_buf_iommufd_map().
I also plan another series to modify iommufd's vfio_compat to
transparently pull a dmabuf out of a VFIO VMA to emulate more of the uAPI
of type1.
The latest series for interconnect negotation to exchange a phys_addr is:
https://lore.kernel.org/r/20251027044712.1676175-1-vivek.kasireddy@intel.com
And the discussion for design of revoke is here:
https://lore.kernel.org/dri-devel/20250114173103.GE5556@nvidia.com/
This is on github: https://github.com/jgunthorpe/linux/commits/iommufd_dmabuf
v2:
- Rebase on Leon's v9
- Fix mislocking in an iopt_fill_domain() error path
- Revise the comments around how the sub page offset works
- Remove a useless WARN_ON in iopt_pages_rw_access()
- Fixed missed memory free in the selftest
v1: https://patch.msgid.link/r/0-v1-64bed2430cdb+31b-iommufd_dmabuf_jgg@nvidia.…
Jason Gunthorpe (9):
vfio/pci: Add vfio_pci_dma_buf_iommufd_map()
iommufd: Add DMABUF to iopt_pages
iommufd: Do not map/unmap revoked DMABUFs
iommufd: Allow a DMABUF to be revoked
iommufd: Allow MMIO pages in a batch
iommufd: Have pfn_reader process DMABUF iopt_pages
iommufd: Have iopt_map_file_pages convert the fd to a file
iommufd: Accept a DMABUF through IOMMU_IOAS_MAP_FILE
iommufd/selftest: Add some tests for the dmabuf flow
drivers/iommu/iommufd/io_pagetable.c | 78 +++-
drivers/iommu/iommufd/io_pagetable.h | 54 ++-
drivers/iommu/iommufd/ioas.c | 8 +-
drivers/iommu/iommufd/iommufd_private.h | 14 +-
drivers/iommu/iommufd/iommufd_test.h | 10 +
drivers/iommu/iommufd/main.c | 10 +
drivers/iommu/iommufd/pages.c | 414 ++++++++++++++++--
drivers/iommu/iommufd/selftest.c | 143 ++++++
drivers/vfio/pci/vfio_pci_dmabuf.c | 34 ++
include/linux/vfio_pci_core.h | 4 +
tools/testing/selftests/iommu/iommufd.c | 43 ++
tools/testing/selftests/iommu/iommufd_utils.h | 44 ++
12 files changed, 786 insertions(+), 70 deletions(-)
base-commit: f836737ed56db9e2d5b047c56a31e05af0f3f116
--
2.43.0
The devpts_pts selftest has an ifdef in case an architecture does not
define TIOCGPTPEER, but the handling for this is broken since we need
errno to be set to EINVAL in order to skip the test as we should. Given
that this ioctl() has been defined since v4.15 we may as well just assume
it's there rather than write handling code which will probably never get
used.
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
tools/testing/selftests/filesystems/devpts_pts.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/tools/testing/selftests/filesystems/devpts_pts.c b/tools/testing/selftests/filesystems/devpts_pts.c
index b1fc9b916ace..cad7da1bd7ca 100644
--- a/tools/testing/selftests/filesystems/devpts_pts.c
+++ b/tools/testing/selftests/filesystems/devpts_pts.c
@@ -100,7 +100,7 @@ static int resolve_procfd_symlink(int fd, char *buf, size_t buflen)
static int do_tiocgptpeer(char *ptmx, char *expected_procfd_contents)
{
int ret;
- int master = -1, slave = -1, fret = -1;
+ int master = -1, slave, fret = -1;
master = open(ptmx, O_RDWR | O_NOCTTY | O_CLOEXEC);
if (master < 0) {
@@ -119,9 +119,7 @@ static int do_tiocgptpeer(char *ptmx, char *expected_procfd_contents)
goto do_cleanup;
}
-#ifdef TIOCGPTPEER
slave = ioctl(master, TIOCGPTPEER, O_RDWR | O_NOCTTY | O_CLOEXEC);
-#endif
if (slave < 0) {
if (errno == EINVAL) {
fprintf(stderr, "TIOCGPTPEER is not supported. "
---
base-commit: ac3fd01e4c1efce8f2c054cdeb2ddd2fc0fb150d
change-id: 20251126-selftests-filesystems-devpts-tiocgptpeer-fbd30e579859
Best regards,
--
Mark Brown <broonie(a)kernel.org>
From: Jack Thomson <jackabt(a)amazon.com>
This patch series adds ARM64 support for the KVM_PRE_FAULT_MEMORY
feature, which was previously only available on x86 [1]. This allows us
to reduce the number of stage-2 faults during execution. This is of
benefit in post-copy migration scenarios, particularly in memory
intensive applications, where we are experiencing high latencies due to
the stage-2 faults.
Patch Overview:
- The first patch adds support for the KVM_PRE_FAULT_MEMORY ioctl
on arm64.
- The second patch updates the pre_fault_memory_test to support
arm64.
- The last patch extends the pre_fault_memory_test to cover
different vm memory backings.
=== Changes Since v2 [2] ===
- Update fault info synthesize value. Thanks Suzuki
- Remove change to selftests for unaligned mmap allocations. Thanks
Sean
[1]: https://lore.kernel.org/kvm/20240710174031.312055-1-pbonzini@redhat.com
[2]: https://lore.kernel.org/linux-arm-kernel/20251013151502.6679-1-jackabt.amaz…
Jack Thomson (3):
KVM: arm64: Add pre_fault_memory implementation
KVM: selftests: Enable pre_fault_memory_test for arm64
KVM: selftests: Add option for different backing in pre-fault tests
Documentation/virt/kvm/api.rst | 3 +-
arch/arm64/kvm/Kconfig | 1 +
arch/arm64/kvm/arm.c | 1 +
arch/arm64/kvm/mmu.c | 73 +++++++++++-
tools/testing/selftests/kvm/Makefile.kvm | 1 +
.../selftests/kvm/pre_fault_memory_test.c | 110 ++++++++++++++----
6 files changed, 159 insertions(+), 30 deletions(-)
base-commit: 8a4821412cf2c1429fffa07c012dd150f2edf78c
--
2.43.0
The series is separated from [1] to show the independency and compare
potential use cases easier. This use case uses the primitive revocable
APIs directly. It relies on the revocable core part [2].
It tries to fix an UAF in the fops of cros_ec_chardev after the
underlying protocol device has gone by using revocable.
The file operations make sure the resources are available when using them.
Even though it has the finest grain for accessing the resources, it makes
the user code verbose. Per feedback from the community, I'm looking for
some subsystem level helpers so that user code can be simlper.
The 1st patch converts existing protocol devices to resource providers
of cros_ec_device.
The 2nd patch converts cros_ec_chardev to a resource consumer of
cros_ec_device to fix the UAF.
[1] https://lore.kernel.org/chrome-platform/20251016054204.1523139-1-tzungbi@ke…
[2] https://lore.kernel.org/chrome-platform/20251106152330.11733-1-tzungbi@kern…
v6:
- New, separated from an existing series.
Tzung-Bi Shih (2):
platform/chrome: Protect cros_ec_device lifecycle with revocable
platform/chrome: cros_ec_chardev: Consume cros_ec_device via revocable
drivers/platform/chrome/cros_ec.c | 5 ++
drivers/platform/chrome/cros_ec_chardev.c | 71 ++++++++++++++++-----
include/linux/platform_data/cros_ec_proto.h | 4 ++
3 files changed, 65 insertions(+), 15 deletions(-)
--
2.48.1
For a while now we have supported file handles for pidfds. This has
proven to be very useful.
Extend the concept to cover namespaces as well. After this patchset it
is possible to encode and decode namespace file handles using the
commong name_to_handle_at() and open_by_handle_at() apis.
Namespaces file descriptors can already be derived from pidfds which
means they aren't subject to overmount protection bugs. IOW, it's
irrelevant if the caller would not have access to an appropriate
/proc/<pid>/ns/ directory as they could always just derive the namespace
based on a pidfd already.
It has the same advantage as pidfds. It's possible to reliably and for
the lifetime of the system refer to a namespace without pinning any
resources and to compare them.
Permission checking is kept simple. If the caller is located in the
namespace the file handle refers to they are able to open it otherwise
they must hold privilege over the owning namespace of the relevant
namespace.
Both the network namespace and the mount namespace already have an
associated cookie that isn't recycled and is fully exposed to userspace.
Move this into ns_common and use the same id space for all namespaces so
they can trivially and reliably be compared.
There's more coming based on the iterator infrastructure but the series
is large enough and focuses on file handles.
Extensive selftests included. I still have various other test-suites to
run but it holds up so far.
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
---
Christian Brauner (32):
pidfs: validate extensible ioctls
nsfs: validate extensible ioctls
block: use extensible_ioctl_valid()
ns: move to_ns_common() to ns_common.h
nsfs: add nsfs.h header
ns: uniformly initialize ns_common
mnt: use ns_common_init()
ipc: use ns_common_init()
cgroup: use ns_common_init()
pid: use ns_common_init()
time: use ns_common_init()
uts: use ns_common_init()
user: use ns_common_init()
net: use ns_common_init()
ns: remove ns_alloc_inum()
nstree: make iterator generic
mnt: support iterator
cgroup: support iterator
ipc: support iterator
net: support iterator
pid: support iterator
time: support iterator
userns: support iterator
uts: support iterator
ns: add to_<type>_ns() to respective headers
nsfs: add current_in_namespace()
nsfs: support file handles
nsfs: support exhaustive file handles
nsfs: add missing id retrieval support
tools: update nsfs.h uapi header
selftests/namespaces: add identifier selftests
selftests/namespaces: add file handle selftests
block/blk-integrity.c | 8 +-
fs/fhandle.c | 6 +
fs/internal.h | 1 +
fs/mount.h | 10 +-
fs/namespace.c | 156 +--
fs/nsfs.c | 266 +++-
fs/pidfs.c | 2 +-
include/linux/cgroup.h | 5 +
include/linux/exportfs.h | 6 +
include/linux/fs.h | 14 +
include/linux/ipc_namespace.h | 5 +
include/linux/ns_common.h | 29 +
include/linux/nsfs.h | 40 +
include/linux/nsproxy.h | 11 -
include/linux/nstree.h | 89 ++
include/linux/pid_namespace.h | 5 +
include/linux/proc_ns.h | 32 +-
include/linux/time_namespace.h | 9 +
include/linux/user_namespace.h | 5 +
include/linux/utsname.h | 5 +
include/net/net_namespace.h | 6 +
include/uapi/linux/fcntl.h | 1 +
include/uapi/linux/nsfs.h | 12 +-
init/main.c | 2 +
ipc/msgutil.c | 1 +
ipc/namespace.c | 12 +-
ipc/shm.c | 2 +
kernel/Makefile | 2 +-
kernel/cgroup/cgroup.c | 2 +
kernel/cgroup/namespace.c | 24 +-
kernel/nstree.c | 233 ++++
kernel/pid_namespace.c | 13 +-
kernel/time/namespace.c | 23 +-
kernel/user_namespace.c | 17 +-
kernel/utsname.c | 28 +-
net/core/net_namespace.c | 59 +-
tools/include/uapi/linux/nsfs.h | 23 +-
tools/testing/selftests/namespaces/.gitignore | 2 +
tools/testing/selftests/namespaces/Makefile | 7 +
tools/testing/selftests/namespaces/config | 7 +
.../selftests/namespaces/file_handle_test.c | 1410 ++++++++++++++++++++
tools/testing/selftests/namespaces/nsid_test.c | 986 ++++++++++++++
42 files changed, 3306 insertions(+), 270 deletions(-)
---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250905-work-namespace-c68826dda0d4
This series improves the CPU cost of RX token management by adding an
attribute to NETDEV_CMD_BIND_RX that configures sockets using the
binding to avoid the xarray allocator and instead use a per-binding niov
array and a uref field in niov.
Improvement is ~13% cpu util per RX user thread.
Using kperf, the following results were observed:
Before:
Average RX worker idle %: 13.13, flows 4, test runs 11
After:
Average RX worker idle %: 26.32, flows 4, test runs 11
Two other approaches were tested, but with no improvement. Namely, 1)
using a hashmap for tokens and 2) keeping an xarray of atomic counters
but using RCU so that the hotpath could be mostly lockless. Neither of
these approaches proved better than the simple array in terms of CPU.
The attribute NETDEV_A_DMABUF_AUTORELEASE is added to toggle the
optimization. It is an optional attribute and defaults to 0 (i.e.,
optimization on).
To: David S. Miller <davem(a)davemloft.net>
To: Eric Dumazet <edumazet(a)google.com>
To: Jakub Kicinski <kuba(a)kernel.org>
To: Paolo Abeni <pabeni(a)redhat.com>
To: Simon Horman <horms(a)kernel.org>
To: Kuniyuki Iwashima <kuniyu(a)google.com>
To: Willem de Bruijn <willemb(a)google.com>
To: Neal Cardwell <ncardwell(a)google.com>
To: David Ahern <dsahern(a)kernel.org>
To: Mina Almasry <almasrymina(a)google.com>
To: Arnd Bergmann <arnd(a)arndb.de>
To: Jonathan Corbet <corbet(a)lwn.net>
To: Andrew Lunn <andrew+netdev(a)lunn.ch>
To: Shuah Khan <shuah(a)kernel.org>
Cc: Stanislav Fomichev <sdf(a)fomichev.me>
Cc: netdev(a)vger.kernel.org
Cc: linux-kernel(a)vger.kernel.org
Cc: linux-arch(a)vger.kernel.org
Cc: linux-doc(a)vger.kernel.org
Cc: linux-kselftest(a)vger.kernel.org
Signed-off-by: Bobby Eshleman <bobbyeshleman(a)meta.com>
Changes in v7:
- use netlink instead of sockopt (Stan)
- restrict system to only one mode, dmabuf bindings can not co-exist
with different modes (Stan)
- use static branching to enforce single system-wide mode (Stan)
- Link to v6: https://lore.kernel.org/r/20251104-scratch-bobbyeshleman-devmem-tcp-token-u…
Changes in v6:
- renamed 'net: devmem: use niov array for token management' to refer to
optionality of new config
- added documentation and tests
- make autorelease flag per-socket sockopt instead of binding
field / sysctl
- many per-patch changes (see Changes sections per-patch)
- Link to v5: https://lore.kernel.org/r/20251023-scratch-bobbyeshleman-devmem-tcp-token-u…
Changes in v5:
- add sysctl to opt-out of performance benefit, back to old token release
- Link to v4: https://lore.kernel.org/all/20250926-scratch-bobbyeshleman-devmem-tcp-token…
Changes in v4:
- rebase to net-next
- Link to v3: https://lore.kernel.org/r/20250926-scratch-bobbyeshleman-devmem-tcp-token-u…
Changes in v3:
- make urefs per-binding instead of per-socket, reducing memory
footprint
- fallback to cleaning up references in dmabuf unbind if socket
leaked tokens
- drop ethtool patch
- Link to v2: https://lore.kernel.org/r/20250911-scratch-bobbyeshleman-devmem-tcp-token-u…
Changes in v2:
- net: ethtool: prevent user from breaking devmem single-binding rule
(Mina)
- pre-assign niovs in binding->vec for RX case (Mina)
- remove WARNs on invalid user input (Mina)
- remove extraneous binding ref get (Mina)
- remove WARN for changed binding (Mina)
- always use GFP_ZERO for binding->vec (Mina)
- fix length of alloc for urefs
- use atomic_set(, 0) to initialize sk_user_frags.urefs
- Link to v1: https://lore.kernel.org/r/20250902-scratch-bobbyeshleman-devmem-tcp-token-u…
---
Bobby Eshleman (5):
net: devmem: rename tx_vec to vec in dmabuf binding
net: devmem: refactor sock_devmem_dontneed for autorelease split
net: devmem: implement autorelease token management
net: devmem: document NETDEV_A_DMABUF_AUTORELEASE netlink attribute
selftests: drv-net: devmem: add autorelease tests
Documentation/netlink/specs/netdev.yaml | 12 +++
Documentation/networking/devmem.rst | 70 +++++++++++++
include/net/netmem.h | 1 +
include/net/sock.h | 7 +-
include/uapi/linux/netdev.h | 1 +
net/core/devmem.c | 121 ++++++++++++++++++----
net/core/devmem.h | 13 ++-
net/core/netdev-genl-gen.c | 5 +-
net/core/netdev-genl.c | 13 ++-
net/core/sock.c | 103 ++++++++++++++----
net/ipv4/tcp.c | 78 +++++++++++---
net/ipv4/tcp_ipv4.c | 13 ++-
net/ipv4/tcp_minisocks.c | 3 +-
tools/include/uapi/linux/netdev.h | 1 +
tools/testing/selftests/drivers/net/hw/devmem.py | 22 +++-
tools/testing/selftests/drivers/net/hw/ncdevmem.c | 19 ++--
16 files changed, 401 insertions(+), 81 deletions(-)
---
base-commit: 4c52142904b33b41c3ff7ee58670b4e3b3bf1120
change-id: 20250829-scratch-bobbyeshleman-devmem-tcp-token-upstream-292be174d503
Best regards,
--
Bobby Eshleman <bobbyeshleman(a)meta.com>
From: Chia-Yu Chang <chia-yu.chang(a)nokia-bell-labs.com>
Hello,
Plesae find the v5 AccECN case handling patch series, which covers
several excpetional case handling of Accurate ECN spec (RFC9768),
adds new identifiers to be used by CC modules, adds ecn_delta into
rate_sample, and keeps the ACE counter for computation, etc.
This patch series is part of the full AccECN patch series, which is available at
https://github.com/L4STeam/linux-net-next/commits/upstream_l4steam/
Best regards,
Chia-Yu
---
v6:
- Update comment in #3 to highlight RX path is only used for virtio-net (Paolo Abeni <pabeni(a)redhat.com>)
- Rename TCP_CONG_WANTS_ECT_1 to TCP_CONG_ECT_1_NEGOTIATION to distiguish from TCP_CONG_ECT_1_ESTABLISH (Paolo Abeni <pabeni(a)redhat.com>)
- Move TCP_CONG_ECT_1_ESTABLISH in #6 to latter patch series (Paolo Abeni <pabeni(a)redhat.com>)
- Add new synack_type instead of moving the increment of num_retran in #9 (Paolo Abeni <pabeni(a)redhat.com>)
- Use new synack_type TCP_SYNACK_RETRANS and num_retrans for SYN/ACK retx fallbackk for AccECN in #10 (Paolo Abeni <pabeni(a)redhat.com>)
- Do not cast const struct into non-const in #11, and set AccECN fail mode after tcp_rtx_synack() (Paolo Abeni <pabeni(a)redhat.com>)
v5:
- Move previous #11 in v4 in latter patch after discussion with RFC author.
- Add #3 to update the comments for SKB_GSO_TCP_ECN and SKB_GSO_TCP_ACCECN. (Parav Pandit <parav(a)nvidia.com>)
- Add gro self-test for TCP CWR flag in #4. (Eric Dumazet <edumazet(a)google.com>)
- Add fixes: tag into #7 (Paolo Abeni <pabeni(a)redhat.com>)
- Update commit message of #8 and if condition check (Paolo Abeni <pabeni(a)redhat.com>)
- Add empty line between variable declarations and code in #13 (Paolo Abeni <pabeni(a)redhat.com>)
v4:
- Add previous #13 in v2 back after dicussion with the RFC author.
- Add TCP_ACCECN_OPTION_PERSIST to tcp_ecn_option sysctl to ignore AccECN fallback policy on sending AccECN option.
v3:
- Add additional min() check if pkts_acked_ewma is not initialized in #1. (Paolo Abeni <pabeni(a)redhat.com>)
- Change TCP_CONG_WANTS_ECT_1 into individual flag add helper function INET_ECN_xmit_wants_ect_1() in #3. (Paolo Abeni <pabeni(a)redhat.com>)
- Add empty line between variable declarations and code in #4. (Paolo Abeni <pabeni(a)redhat.com>)
- Update commit message to fix old AccECN commits in #5. (Paolo Abeni <pabeni(a)redhat.com>)
- Remove unnecessary brackets in #10. (Paolo Abeni <pabeni(a)redhat.com>)
- Move patch #3 in v2 to a later Prague patch serise and remove patch #13 in v2. (Paolo Abeni <pabeni(a)redhat.com>)
---
Chia-Yu Chang (12):
net: update commnets for SKB_GSO_TCP_ECN and SKB_GSO_TCP_ACCECN
selftests/net: gro: add self-test for TCP CWR flag
tcp: ECT_1_NEGOTIATION and NEEDS_ACCECN identifiers
tcp: disable RFC3168 fallback identifier for CC modules
tcp: accecn: handle unexpected AccECN negotiation feedback
tcp: accecn: retransmit downgraded SYN in AccECN negotiation
tcp: add TCP_SYNACK_RETRANS synack_type
tcp: accecn: retransmit SYN/ACK without AccECN option or non-AccECN
SYN/ACK
tcp: accecn: unset ECT if receive or send ACE=0 in AccECN negotiaion
tcp: accecn: fallback outgoing half link to non-AccECN
tcp: accecn: detect loss ACK w/ AccECN option and add
TCP_ACCECN_OPTION_PERSIST
tcp: accecn: enable AccECN
Ilpo Järvinen (2):
tcp: try to avoid safer when ACKs are thinned
gro: flushing when CWR is set negatively affects AccECN
Documentation/networking/ip-sysctl.rst | 4 +-
.../networking/net_cachelines/tcp_sock.rst | 1 +
include/linux/skbuff.h | 14 ++-
include/linux/tcp.h | 4 +-
include/net/inet_ecn.h | 20 +++-
include/net/tcp.h | 32 ++++++-
include/net/tcp_ecn.h | 92 ++++++++++++++-----
net/ipv4/inet_connection_sock.c | 4 +
net/ipv4/sysctl_net_ipv4.c | 4 +-
net/ipv4/tcp.c | 2 +
net/ipv4/tcp_cong.c | 5 +-
net/ipv4/tcp_input.c | 37 +++++++-
net/ipv4/tcp_minisocks.c | 46 +++++++---
net/ipv4/tcp_offload.c | 3 +-
net/ipv4/tcp_output.c | 32 ++++---
net/ipv4/tcp_timer.c | 3 +
tools/testing/selftests/net/gro.c | 80 +++++++++++-----
17 files changed, 295 insertions(+), 88 deletions(-)
--
2.34.1