Problem
-------
The expected initial state of the table depends on feature negotiation:
With VIRTIO_NET_F_CTRL_VLAN:
The table must be empty in accordance with the specification.
Without VIRTIO_NET_F_CTRL_VLAN:
The table must be filled to permit all VLAN traffic.
Prior to commit 06b636a1e2 ("virtio-net: do not reset vlan filtering
at set_features"), virtio_net_set_features() always reset the VLAN
table. That commit changed the behavior to skip table reset when
VIRTIO_NET_F_CTRL_VLAN was negotiated, assuming the table would be
properly cleared during device reset and remain stable.
However, this assumption breaks when a driver renegotiates features:
1. Initial negotiation without VIRTIO_NET_F_CTRL_VLAN (table filled)
2. Renegotiation with VIRTIO_NET_F_CTRL_VLAN (table will not be cleared)
The problem was exacerbated by commit 0caed25cd1 ("virtio: Call
set_features during reset"), which triggered virtio_net_set_features()
during device reset, exposing the bug whenever VIRTIO_NET_F_CTRL_VLAN
was negotiated after a device reset.
Solution
--------
Fix the issue by initializing the table when virtio_net_set_features()
is called to change the VIRTIO_NET_F_CTRL_VLAN bit of
vdev->guest_features.
This approach ensures the correct table state regardless of feature
negotiation sequence by performing initialization in
virtio_net_set_features() as QEMU did prior to commit 06b636a1e2
("virtio-net: do not reset vlan filtering at set_features").
This change still preserves the goal of the commit, which was to avoid
resetting the table during migration, by checking whether the
VIRTIO_NET_F_CTRL_VLAN bit of vdev->guest_features is being changed;
vdev->guest_features is set before virtio_net_set_features() gets called
during migration.
It also avoids resetting the table when the driver sets a feature
bitmask with no change for the VIRTIO_NET_F_CTRL_VLAN bit, which makes
the operation idempotent and its semantics cleaner.
Additionally, this change ensures the table is initialized after
feature negotiation and before the DRIVER_OK status bit being set for
compatibility with the Linux driver before commit 50c0ada627f5
("virtio-net: fix race between ndo_open() and virtio_device_ready()"),
which did not ensure to set the DRIVER_OK status bit before modifying
the table.
Fixes: 06b636a1e2 ("virtio-net: do not reset vlan filtering at set_features")
Cc: qemu-stable@nongnu.org
Reported-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Tested-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Message-Id: <20250727-vlan-v3-1-bbee738619b1@rsg.ci.i.u-tokyo.ac.jp>
Tested-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
SPCR acpi table can now be disabled
vhost-vdpa can now report hashing capability to guest
PPTT acpi table now tells guest vCPUs are identical
vost-user-blk now shuts down faster
loongarch64 now supports bios-tables-test
intel_iommu now supports ATS
cxl now supports DCD Fabric Management Command Set
arm now supports acpi pci hotplug
fixes, cleanups
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu into staging
virtio,pci,pc: features, fixes, tests
SPCR acpi table can now be disabled
vhost-vdpa can now report hashing capability to guest
PPTT acpi table now tells guest vCPUs are identical
vost-user-blk now shuts down faster
loongarch64 now supports bios-tables-test
intel_iommu now supports ATS
cxl now supports DCD Fabric Management Command Set
arm now supports acpi pci hotplug
fixes, cleanups
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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# gpg: Signature made Tue 15 Jul 2025 02:56:48 EDT
# gpg: using RSA key 5D09FD0871C8F85B94CA8A0D281F0DB8D28D5469
# gpg: issuer "mst@redhat.com"
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [full]
# gpg: aka "Michael S. Tsirkin <mst@redhat.com>" [full]
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17 0970 C350 3912 AFBE 8E67
# Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA 8A0D 281F 0DB8 D28D 5469
* tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu: (97 commits)
hw/cxl: mailbox-utils: 0x5605 - FMAPI Initiate DC Release
hw/cxl: mailbox-utils: 0x5604 - FMAPI Initiate DC Add
hw/cxl: Create helper function to create DC Event Records from extents
hw/cxl: mailbox-utils: 0x5603 - FMAPI Get DC Region Extent Lists
hw/cxl: mailbox-utils: 0x5602 - FMAPI Set DC Region Config
hw/mem: cxl_type3: Add DC Region bitmap lock
hw/cxl: Move definition for dynamic_capacity_uuid and enum for DC event types to header
hw/cxl: mailbox-utils: 0x5601 - FMAPI Get Host Region Config
hw/mem: cxl_type3: Add dsmas_flags to CXLDCRegion struct
hw/cxl: mailbox-utils: 0x5600 - FMAPI Get DCD Info
hw/cxl: fix DC extent capacity tracking
tests: virt: Update expected ACPI tables for virt test
hw/acpi/aml-build: Build a root node in the PPTT table
hw/acpi/aml-build: Set identical implementation flag for PPTT processor nodes
tests: virt: Allow changes to PPTT test table
qtest/bios-tables-test: Generate reference blob for DSDT.acpipcihp
qtest/bios-tables-test: Generate reference blob for DSDT.hpoffacpiindex
tests/qtest/bios-tables-test: Add aarch64 ACPI PCI hotplug test
tests/qtest/bios-tables-test: Prepare for addition of acpi pci hp tests
hw/arm/virt: Let virt support pci hotplug/unplug GED event
...
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Conflicts:
net/vhost-vdpa.c
vhost_vdpa_set_steering_ebpf() was removed, resolve the context
conflict.
By default, virtio-net limits the hash types that will be advertised to
the guest so that all hash types are covered by the offloading
capability the client provides. This change allows to override this
behavior and to advertise hash types that require user-space hash
calculation by specifying "on" for the corresponding properties.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250530-vdpa-v1-6-5af4109b1c19@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Retrieve peer hashing capability instead of hardcoding.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250530-vdpa-v1-4-5af4109b1c19@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Move virtio_net_get_features() to the later part of the file so that
it can call other functions.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250530-vdpa-v1-3-5af4109b1c19@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Introduce a boolean is_vhost_user field to the vhost_net
structure. This flag is initialized during vhost_net_init based
on whether the backend is vhost-user.
This refactoring simplifies checks for vhost-user specific behavior,
replacing direct comparisons of 'net->nc->info->type' with the new
flag. It improves readability and encapsulates the backend type
information directly within the vhost_net instance.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit refactors how the maximum transmit queue size for
virtio-net devices is determined, making the mechanism more generic
and extensible.
Previously, virtio_net_max_tx_queue_size() contained hardcoded
checks for specific network backend types (vhost-user and
vhost-vdpa) to determine their supported maximum queue size. This
created direct dependencies and would require modifications for
every new backend that supports variable queue sizes.
To improve flexibility, a new max_tx_queue_size field is added
to the vhost_net structure. This allows each network backend
to advertise its supported maximum transmit queue size directly.
The virtio_net_max_tx_queue_size() function now retrieves the max
TX queue size from the vhost_net struct, if available and set.
Otherwise, it defaults to VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This is a cosmetic change with no functional impact.
The function vhost_set_vring_enable() is specific to vhost_net and
is used outside of vhost_net.c (specifically, in
hw/net/virtio-net.c). To prevent confusion with other similarly named
vhost functions, such as the one found in cryptodev-vhost.c, it has
been renamed to vhost_net_set_vring_enable(). This clarifies that the
function belongs to the vhost_net module.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
virtio_net_pre_load_queues() inspects vdev->guest_features to tell if
VIRTIO_NET_F_RSS or VIRTIO_NET_F_MQ is enabled to infer the required
number of queues. This works for VIRTIO_NET_F_MQ but it doesn't for
VIRTIO_NET_F_RSS because only the lowest 32 bits of vdev->guest_features
is set at the point and VIRTIO_NET_F_RSS uses bit 60 while
VIRTIO_NET_F_MQ uses bit 22.
Instead of inferring the required number of queues from
vdev->guest_features, use the number loaded from the vm state. This
change also has a nice side effect to remove a duplicate peer queue
pair change by circumventing virtio_net_set_multiqueue().
Also update the comment in include/hw/virtio/virtio.h to prevent an
implementation of pre_load_queues() from refering to any fields being
loaded during migration by accident in the future.
Fixes: 8c49756825 ("virtio-net: Add only one queue pair when realizing")
Tested-by: Lei Yang <leiyang@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The 'virtio_net_receive_rcu' method has three arrays with
VIRTQUEUE_MAX_SIZE elements, which are apprixmately 32k in
size used for copying data between guest and host. Skip the
automatic zero-init of these arrays to eliminate the
performance overhead in the I/O hot path.
The three arrays will be selectively initialized as required
when processing network buffers.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-22-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Live migration should be terminated if the vhost-user backend crashes
before the migration completes.
Specifically, since the vhost device will be stopped when VM is stopped
before the end of the live migration, in current implementation if the
backend crashes, vhost-user device set_status() won't return failure,
live migration won't perceive the disconnection between QEMU and the
backend.
When the VM is migrated to the destination, the inflight IO will be
resubmitted, and if the IO was completed out of order before, it will
cause IO error.
To fix this issue:
1. Add the return value to set_status() for VirtioDeviceClass.
a. For the vhost-user device, return failure when the backend crashes.
b. For other virtio devices, always return 0.
2. Return failure if vhost_dev_stop() failed for vhost-user device.
If QEMU loses connection with the vhost-user backend, virtio set_status()
can return failure to the upper layer, migration_completion() can handle
the error, terminate the live migration, and restore the VM, so that
inflight IO can be completed normally.
Signed-off-by: Haoqian He <haoqian.he@smartx.com>
Message-Id: <20250416024729.3289157-4-haoqian.he@smartx.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Mechanical change using gsed, then style manually adapted
to pass checkpatch.pl script.
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250424194905.82506-4-philmd@linaro.org>
This reverts commit 7987d2be5a.
The goal was to remove the need to patch the (const) input buffer
with a recomputed UDP checksum by copying headers to a RW region and
inject the checksum there. The patch computed the checksum only from the
header fields (missing the rest of the payload) producing an invalid one
and making guests fail to acquire a DHCP lease.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2727
Cc: qemu-stable@nongnu.org
Signed-off-by: Antoine Damhet <adamhet@scaleway.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20250408145345.142947-1-adamhet@scaleway.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The specification says the device MUST set num_buffers to 1 if
VIRTIO_NET_F_MRG_RXBUF has not been negotiated.
Fixes: df91055db5 ("virtio-net: enable virtio 1.0")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250108-buffers-v1-1-a0c85ff31aeb@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Features:
SR-IOV emulation for pci
virtio-mem-pci support for s390
interleave support for cxl
big endian support for vdpa svq
new QAPI events for vhost-user
Also vIOMMU reset order fixups are in.
Fixes, cleanups all over the place.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu into staging
virtio,pc,pci: features, fixes, cleanups
Features:
SR-IOV emulation for pci
virtio-mem-pci support for s390
interleave support for cxl
big endian support for vdpa svq
new QAPI events for vhost-user
Also vIOMMU reset order fixups are in.
Fixes, cleanups all over the place.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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# gpg: Signature made Fri 21 Feb 2025 20:21:31 HKT
# gpg: using RSA key 5D09FD0871C8F85B94CA8A0D281F0DB8D28D5469
# gpg: issuer "mst@redhat.com"
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [full]
# gpg: aka "Michael S. Tsirkin <mst@redhat.com>" [full]
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17 0970 C350 3912 AFBE 8E67
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* tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu: (41 commits)
docs/devel/reset: Document reset expectations for DMA and IOMMU
hw/vfio/common: Add a trace point in vfio_reset_handler
hw/arm/smmuv3: Move reset to exit phase
hw/i386/intel-iommu: Migrate to 3-phase reset
hw/virtio/virtio-iommu: Migrate to 3-phase reset
vhost-user-snd: correct the calculation of config_size
net: vhost-user: add QAPI events to report connection state
hw/virtio/virtio-nsm: Respond with correct length
vdpa: Fix endian bugs in shadow virtqueue
MAINTAINERS: add more files to `vhost`
cryptodev/vhost: allocate CryptoDevBackendVhost using g_mem0()
vhost-iova-tree: Update documentation
vhost-iova-tree, svq: Implement GPA->IOVA & partial IOVA->HVA trees
vhost-iova-tree: Implement an IOVA-only tree
amd_iommu: Use correct bitmask to set capability BAR
amd_iommu: Use correct DTE field for interrupt passthrough
hw/virtio: reset virtio balloon stats on machine reset
mem/cxl_type3: support 3, 6, 12 and 16 interleave ways
hw/mem/cxl_type3: Ensure errp is set on realization failure
hw/mem/cxl_type3: Fix special_ops memory leak on msix_init_exclusive_bar() failure
...
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
When an eBPF program cannot be attached, virtio_net_load_ebpf() returns
false, and virtio_net_device_realize() enters the code path to handle
errors because of this, but it causes NULL dereference because no error
is generated.
Change virtio_net_load_ebpf() to return false only when a fatal error
occurred.
Fixes: b5900dff14 ("hw/net: report errors from failing to use eBPF RSS FDs")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20250116-software-v1-1-9e5161b534d8@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The general expectation is that header files should follow the same
file/path naming scheme as the corresponding source file. There are
various historical exceptions to this practice in QEMU, with one of
the most notable being the include/qapi/qmp/ directory. Most of the
headers there correspond to source files in qobject/.
This patch corrects most of that inconsistency by creating
include/qobject/ and moving the headers for qobject/ there.
This also fixes MAINTAINERS for include/qapi/qmp/dispatch.h:
scripts/get_maintainer.pl now reports "QAPI" instead of "No
maintainers found".
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com> #s390x
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20241118151235.2665921-2-armbru@redhat.com>
[Rebased]
Add support of VHOST_USER_PROTOCOL_F_DEVICE_STATE in virtio-net
with vhost-user backend.
Cc: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20250115135044.799698-3-lvivier@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Headers in include/sysemu/ are not only related to system
*emulation*, they are also used by virtualization. Rename
as system/ which is clearer.
Files renamed manually then mechanical change using sed tool.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Message-Id: <20241203172445.28576-1-philmd@linaro.org>
Now that all of the Property arrays are counted, we can remove
the terminator object from each array. Update the assertions
in device_class_set_props to match.
With struct Property being 88 bytes, this was a rather large
form of terminator. Saves 30k from qemu-system-aarch64.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Link: https://lore.kernel.org/r/20241218134251.4724-21-richard.henderson@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Call virtio_net_set_multiqueue() to add queues before loading their
states. Otherwise the loaded queues will not have handlers and elements
in them will not be processed.
Cc: qemu-stable@nongnu.org
Fixes: 8c49756825 ("virtio-net: Add only one queue pair when realizing")
Reported-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
receive_header() used to cast the const qualifier of the pointer to the
received packet away to modify the header. Avoid this by copying the
received header to buffer.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The specification says hash_report should be set to
VIRTIO_NET_HASH_REPORT_NONE if VIRTIO_NET_F_HASH_REPORT is negotiated
but not configured with VIRTIO_NET_CTRL_MQ_RSS_CONFIG. However,
virtio_net_receive_rcu() instead wrote out the content of the extra_hdr
variable, which is not uninitialized in such a case.
Fix this by zeroing the extra_hdr.
Fixes: e22f0603fb ("virtio-net: reference implementation of hash report")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
virtio_net_process_rss() fills the values used for hash reporting, but
the values used to be thrown away with a recursive function call if
the queue changes after RSS. Avoid the function call to keep the values.
Fixes: a4c960eedc ("virtio-net: Do not write hashes to peer buffer")
Buglink: https://issues.redhat.com/browse/RHEL-59572
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
virtio_net_can_receive() checks if the queue is ready, but RSS will
change the queue to use so, strictly speaking, we may still be able to
receive the packet even if the queue initially provided is not ready.
Perform RSS before virtio_net_can_receive() to cover such a case.
Fixes: 4474e37a5b ("virtio-net: implement RX RSS processing")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
work_around_broken_dhclient() accesses IP and UDP headers to detect
relevant packets and to calculate checksums, but it didn't check if
the packet has size sufficient to accommodate them, causing out-of-bound
access hazards. Fix this by correcting the size requirement.
Fixes: 1d41b0c1ec ("Work around dhclient brokenness")
Cc: qemu-stable@nongnu.org
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
In virtio-net.c we assume that the IP length field in the packet is
aligned, and we copy its address into a uint16_t* in the
VirtioNetRscUnit struct which we then dereference later. This isn't
a safe assumption; it will also result in compilation failures if we
mark the ip_header struct as QEMU_PACKED because the compiler will
not let you take the address of an unaligned struct field.
Make the ip_plen field in VirtioNetRscUnit a void*, and make all the
places where we read or write through that pointer instead use some
new accessor functions read_unit_ip_len() and write_unit_ip_len()
which account for the pointer being potentially unaligned and also do
the network-byte-order conversion we were previously using htons() to
perform.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20241114141619.806652-2-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
We computes indirections_len by adding 1 to indirection_table_mask, but
it may overflow indirection_table_mask is UINT16_MAX. Check if
indirection_table_mask is small enough before adding 1.
Fixes: 590790297c ("virtio-net: implement RSS configuration command")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This adds more trace events to key eBPF RSS setup operations, and
also distinguishes events from multiple NIC instances.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
If the user/mgmt app passed in a set of pre-opened FDs for eBPF RSS,
then it is expecting QEMU to use them. Any failure to do so must be
considered a fatal error and propagated back up the stack, otherwise
deployment mistakes will not be detectable in a prompt manner. When
not using pre-opened FDs, then eBPF RSS is tried on a "best effort"
basis only and thus fallback to software RSS is valid.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The eBPF code is currently reporting error messages through trace
events. Trace events are fine for debugging, but they are not to be
considered the primary error reporting mechanism, as their output
is inaccessible to callers.
This adds an "Error **errp" parameter to all methods which have
important error scenarios to report to the caller.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Historically, .get_vhost() was probably only called when
vdev->vhost_started is true. However, we now decidedly want to call it
also when vhost_started is false, specifically so we can issue a reset
to the vhost back-end while device operation is stopped.
Some .get_vhost() implementations dereference some pointers (or return
offsets from them) that are probably guaranteed to be non-NULL when
vhost_started is true, but not necessarily otherwise. This patch makes
all such implementations check all such pointers, returning NULL if any
is NULL.
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20240723163941.48775-2-hreitz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Receive coalescing is visible to the target machine, so its timers
should use virtual time like other timers in virtio-net, to be
compatible with record-replay.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20240813050638.446172-10-npiggin@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240813202329.1237572-18-alex.bennee@linaro.org>
The regular qemu_bh_schedule() calls result in non-deterministic
execution of the bh in record-replay mode, which causes replay failure.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20240813050638.446172-9-npiggin@gmail.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240813202329.1237572-17-alex.bennee@linaro.org>
Patch 06b1297017 ("virtio-net: fix network stall under load")
added double-check to test whether the available buffer size
can satisfy the request or not, in case the guest has added
some buffers to the avail ring simultaneously after the first
check. It will be lucky if the available buffer size becomes
okay after the double-check, then the host can send the packet
to the guest. If the buffer size still can't satisfy the request,
even if the guest has added some buffers, viritio-net would
stall at the host side forever.
The patch enables notification and checks whether the guest has
added some buffers since last check of available buffers when
the available buffers are insufficient. If no buffer is added,
return false, else recheck the available buffers in the loop.
If the available buffers are sufficient, disable notification
and return true.
Changes:
1. Change the return type of virtqueue_get_avail_bytes() from void
to int, it returns an opaque that represents the shadow_avail_idx
of the virtqueue on success, else -1 on error.
2. Add a new API: virtio_queue_enable_notification_and_check(),
it takes an opaque as input arg which is returned from
virtqueue_get_avail_bytes(). It enables notification firstly,
then checks whether the guest has added some buffers since
last check of available buffers or not by virtio_queue_poll(),
return ture if yes.
The patch also reverts patch "06b12970174".
The case below can reproduce the stall.
Guest 0
+--------+
| iperf |
---------------> | server |
Host | +--------+
+--------+ | ...
| iperf |----
| client |---- Guest n
+--------+ | +--------+
| | iperf |
---------------> | server |
+--------+
Boot many guests from qemu with virtio network:
qemu ... -netdev tap,id=net_x \
-device virtio-net-pci-non-transitional,\
iommu_platform=on,mac=xx:xx:xx:xx:xx:xx,netdev=net_x
Each guest acts as iperf server with commands below:
iperf3 -s -D -i 10 -p 8001
iperf3 -s -D -i 10 -p 8002
The host as iperf client:
iperf3 -c guest_IP -p 8001 -i 30 -w 256k -P 20 -t 40000
iperf3 -c guest_IP -p 8002 -i 30 -w 256k -P 20 -t 40000
After some time, the host loses connection to the guest,
the guest can send packet to the host, but can't receive
packet from the host.
It's more likely to happen if SWIOTLB is enabled in the guest,
allocating and freeing bounce buffer takes some CPU ticks,
copying from/to bounce buffer takes more CPU ticks, compared
with that there is no bounce buffer in the guest.
Once the rate of producing packets from the host approximates
the rate of receiveing packets in the guest, the guest would
loop in NAPI.
receive packets ---
| |
v |
free buf virtnet_poll
| |
v |
add buf to avail ring ---
|
| need kick the host?
| NAPI continues
v
receive packets ---
| |
v |
free buf virtnet_poll
| |
v |
add buf to avail ring ---
|
v
... ...
On the other hand, the host fetches free buf from avail
ring, if the buf in the avail ring is not enough, the
host notifies the guest the event by writing the avail
idx read from avail ring to the event idx of used ring,
then the host goes to sleep, waiting for the kick signal
from the guest.
Once the guest finds the host is waiting for kick singal
(in virtqueue_kick_prepare_split()), it kicks the host.
The host may stall forever at the sequences below:
Host Guest
------------ -----------
fetch buf, send packet receive packet ---
... ... |
fetch buf, send packet add buf |
... add buf virtnet_poll
buf not enough avail idx-> add buf |
read avail idx add buf |
add buf ---
receive packet ---
write event idx ... |
wait for kick add buf virtnet_poll
... |
---
no more packet, exit NAPI
In the first loop of NAPI above, indicated in the range of
virtnet_poll above, the host is sending packets while the
guest is receiving packets and adding buffers.
step 1: The buf is not enough, for example, a big packet
needs 5 buf, but the available buf count is 3.
The host read current avail idx.
step 2: The guest adds some buf, then checks whether the
host is waiting for kick signal, not at this time.
The used ring is not empty, the guest continues
the second loop of NAPI.
step 3: The host writes the avail idx read from avail
ring to used ring as event idx via
virtio_queue_set_notification(q->rx_vq, 1).
step 4: At the end of the second loop of NAPI, recheck
whether kick is needed, as the event idx in the
used ring written by the host is beyound the
range of kick condition, the guest will not
send kick signal to the host.
Fixes: 06b1297017 ("virtio-net: fix network stall under load")
Cc: qemu-stable@nongnu.org
Signed-off-by: Wencheng Yang <east.moutain.yang@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Ensure the queue index points to a valid queue when software RSS
enabled. The new calculation matches with the behavior of Linux's TAP
device with the RSS eBPF program.
Fixes: 4474e37a5b ("virtio-net: implement RX RSS processing")
Reported-by: Zhibin Hu <huzhibin5@huawei.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
A crash found while fuzzing device virtio-net-socket-check-used.
Assertion "offset == 0" in iov_copy() fails if less than guest_hdr_len bytes
were transmited.
Signed-off-by: Dmitry Frolov <frolov@swemel.ru>
Message-Id: <20240613143529.602591-2-frolov@swemel.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reproducer from https://gitlab.com/qemu-project/qemu/-/issues/1451
creates small packet (1 segment, len = 10 == n->guest_hdr_len),
then destroys queue.
"if (n->host_hdr_len != n->guest_hdr_len)" is triggered, if body creates
zero length/zero segment packet as there is nothing after guest header.
qemu_sendv_packet_async() tries to send it.
slirp discards it because it is smaller than Ethernet header,
but returns 0 because tx hooks are supposed to return total length of data.
0 is propagated upwards and is interpreted as "packet has been sent"
which is terrible because queue is being destroyed, nobody is waiting for TX
to complete and assert it triggered.
Fix is discard such empty packets instead of sending them.
Length 1 packets will go via different codepath:
virtqueue_push(q->tx_vq, elem, 0);
virtio_notify(vdev, q->tx_vq);
g_free(elem);
and aren't problematic.
Signed-off-by: Alexey Dobriyan <adobriyan@yandex-team.ru>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The peer buffer is qualified with const and not meant to be modified.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The member is not cleared during reset so may have a stale value.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The code to attach or detach the eBPF program to RSS were duplicated so
unify them into one function to save some code.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
RSS is disabled by default.
Fixes: 590790297c ("virtio-net: implement RSS configuration command")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Byte swapping is only performed for the part of header shared with the
legacy standard and the buffer only needs to cover it.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The copied header is only used for byte swapping.
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Multiqueue usage is not negotiated yet when realizing. If more than
one queue is added and the guest never requests to enable multiqueue,
the extra queues will not be deleted when unrealizing and leak.
Fixes: f9d6dbf0bf ("virtio-net: remove virtio queues if the guest doesn't support multiqueue")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Propagating ebpf-rss-fds errors has several problems.
First, it makes device realization fail and disables the fallback to the
conventional eBPF loading.
Second, it leaks memory by making device realization fail without
freeing memory already allocated.
Third, the convention is to set an error when a function returns false,
but virtio_net_load_ebpf_fds() and virtio_net_load_ebpf() returns false
without setting an error, which is confusing.
Remove the propagation to fix these problems.
Fixes: 0524ea0510 ("ebpf: Added eBPF initialization by fds.")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Since qemu_set_vnet_hdr_len() is always called when
qemu_using_vnet_hdr() is called, we can merge them and save some code.
For consistency, express that the virtio-net header is not in use by
returning 0 with qemu_get_vnet_hdr_len() instead of having a dedicated
function, qemu_get_using_vnet_hdr().
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
