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[PATCH v2] qemu: Store tapfd path in domstatus XML
by Wesley Hershberger 03 Feb '26

03 Feb '26

Introduce a read-only `tapfd` element for direct interfaces (macvtap), which contains the path to the backing tapfd for that interface (e.g. `/dev/tapXX`). The element is only included when the domain is being formatted for internal consumption (VIR_DOMAIN_DEF_FORMAT_STATUS) and is not accepted in user-provided XML (!VIR_DOMAIN_DEF_PARSE_INACTIVE). This is used by the AppArmor security driver when re-generating profiles. Partial-Resolves: #692 Bug-Ubuntu: https://bugs.launchpad.net/bugs/2126574 Signed-off-by: Wesley Hershberger <wesley.hershberger(a)canonical.com> --- This submission is a partial revision of a previous series with a fix for the macvtap component of gitlab#692 [1][2]. I haven't had bandwidth to resolve the blockcommit component since the complexity there is somewhat higher (and is also lower priority for us). I kept the separate `tapfd` element rather than reusing the existing `backend` element (virDomainNetBackend.tap) to avoid making a user-visible change [3]. I'd be happy to use the existing field instead if you think that would make more sense. I opted not to introduce/modify a security driver API for FD+path as the patch here is sufficient to resolve the bug, but would be willing to do so if that would make this change more palatable. I've opened a MR to libvirt-tck with test cases that demonstrate the bugs that this fixes [4]. apparmor/110-macvtap.t passes with this patch applied. Thanks for the reviews and continued consideration. ~Wesley [1] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/UNNB… [2] https://gitlab.com/libvirt/libvirt/-/issues/692 [3] https://libvirt.org/formatdomain.html#setting-network-backend-specific-opti… [4] https://gitlab.com/libvirt/libvirt-tck/-/merge_requests/73 --- Changes in v2: - Drop `virt-aa-helper: Ask for no deny rule...` as it was applied - Drop `qemu: Store blockcommit permissions...` due to unresolved concerns - Pass tapfd path through netdef instead of resolving from fd - Link to v1: https://lore.kernel.org/r/20260105-apparmor-races-v1-0-932cf0e990b7@canonic… --- src/conf/domain_conf.c | 8 ++++++++ src/conf/domain_conf.h | 1 + src/hypervisor/domain_interface.c | 2 +- src/lxc/lxc_process.c | 1 + src/qemu/qemu_interface.c | 1 + src/security/security_apparmor.c | 1 + src/security/virt-aa-helper.c | 5 +++++ src/util/virnetdevmacvlan.c | 18 +++++++++++------- src/util/virnetdevmacvlan.h | 4 +++- 9 files changed, 32 insertions(+), 9 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 02e23f78667a775637c710b651ba5fc7a127226f..1d7921e0de6f097ffaf86a9197d629e67dc213d7 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -2939,6 +2939,7 @@ virDomainNetDefFree(virDomainNetDef *def) g_free(def->virtio); g_free(def->coalesce); g_free(def->sourceDev); + g_free(def->tapfdpath); virNetDevIPInfoClear(&def->guestIP); virNetDevIPInfoClear(&def->hostIP); @@ -10440,6 +10441,10 @@ virDomainNetDefParseXML(virDomainXMLOption *xmlopt, return NULL; } + if (!(flags & VIR_DOMAIN_DEF_PARSE_INACTIVE)) { + def->tapfdpath = virXPathString("string(./tapfd/@path)", ctxt); + } + if (virNetworkPortOptionsParseXML(ctxt, &def->isolatedPort) < 0) return NULL; @@ -25664,6 +25669,9 @@ virDomainNetDefFormat(virBuffer *buf, if (def->mtu) virBufferAsprintf(buf, "<mtu size='%u'/>\n", def->mtu); + if (def->tapfdpath && (flags & VIR_DOMAIN_DEF_FORMAT_STATUS)) + virBufferAsprintf(buf, "<tapfd path='%s'/>\n", def->tapfdpath); + virDomainNetDefCoalesceFormatXML(buf, def->coalesce); virDomainDeviceInfoFormat(buf, &def->info, flags | VIR_DOMAIN_DEF_FORMAT_ALLOW_BOOT diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 66dc4e3417b8cb5bce60217a4e529add61149962..ba2bf1f750dcd7f4f25ef3bf55fd63629d3b5222 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -1203,6 +1203,7 @@ struct _virDomainNetDef { char *downscript; char *domain_name; /* backend domain name */ char *ifname; /* interface name on the host (<target dev='x'/>) */ + char *tapfdpath; /* Path in /dev for macvtap (<tapfd path="/dev/tapXX">) */ virTristateBool managed_tap; virNetDevIPInfo hostIP; char *ifname_guest_actual; diff --git a/src/hypervisor/domain_interface.c b/src/hypervisor/domain_interface.c index 5bc698d2727e1142e9c5dc30ac00975f268f98e8..37e3d453a03943ee5729ad2d4b087b5e0ca37408 100644 --- a/src/hypervisor/domain_interface.c +++ b/src/hypervisor/domain_interface.c @@ -111,7 +111,7 @@ virDomainInterfaceEthernetConnect(virDomainDef *def, if (virNetDevMacVLanIsMacvtap(net->ifname)) { auditdev = net->ifname; - if (virNetDevMacVLanTapOpen(net->ifname, tapfd, tapfdSize) < 0) + if (virNetDevMacVLanTapOpen(net->ifname, tapfd, tapfdSize, &net->tapfdpath) < 0) goto cleanup; if (virNetDevMacVLanTapSetup(tapfd, tapfdSize, virDomainInterfaceIsVnetCompatModel(net)) < 0) { diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c index 1bca9e8daea2cb8f63bcf5c0a735252ff57af6f1..c731b28871b18329e633c42f2141d22063208d9f 100644 --- a/src/lxc/lxc_process.c +++ b/src/lxc/lxc_process.c @@ -379,6 +379,7 @@ virLXCProcessSetupInterfaceDirect(virLXCDriver *driver, VIR_NETDEV_VPORT_PROFILE_OP_CREATE, cfg->stateDir, NULL, 0, + &net->tapfdpath, macvlan_create_flags) < 0) return NULL; diff --git a/src/qemu/qemu_interface.c b/src/qemu/qemu_interface.c index 23a23d201aec31a36431646551ae03a233606e30..edc53d53b3b34afbfb8662e809bc0898076fdfc5 100644 --- a/src/qemu/qemu_interface.c +++ b/src/qemu/qemu_interface.c @@ -81,6 +81,7 @@ qemuInterfaceDirectConnect(virDomainDef *def, &res_ifname, vmop, cfg->stateDir, tapfd, tapfdSize, + &net->tapfdpath, macvlan_create_flags) < 0) goto cleanup; diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c index 934acfb46198401d84d47cc6266a9403eda5a3b0..dec271721641c811944f98464cebebca6ed6a159 100644 --- a/src/security/security_apparmor.c +++ b/src/security/security_apparmor.c @@ -157,6 +157,7 @@ load_profile(virSecurityManager *mgr G_GNUC_UNUSED, if (virDomainDefFormatInternal(def, NULL, &buf, VIR_DOMAIN_DEF_FORMAT_SECURE | + VIR_DOMAIN_DEF_FORMAT_STATUS | VIR_DOMAIN_DEF_FORMAT_VOLUME_TRANSLATED) < 0) return -1; diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c index f4ec6b7826ba532f0dbac2dcd4ed89f7f98e6be6..e904d5e8292ae5e7d4acbec2062a91861a9535f5 100644 --- a/src/security/virt-aa-helper.c +++ b/src/security/virt-aa-helper.c @@ -1176,6 +1176,11 @@ get_files(vahControl * ctl) vhu->type) != 0) return -1; } + + if (net->tapfdpath) { + if (vah_add_file(&buf, net->tapfdpath, "rwk") != 0) + return -1; + } } for (i = 0; i < ctl->def->nmems; i++) { diff --git a/src/util/virnetdevmacvlan.c b/src/util/virnetdevmacvlan.c index cde9d70eefd047dc5c16056f6697cf4d05bc0795..fcf63e08ff07eca22a122a2532cea1b0c9a95c9e 100644 --- a/src/util/virnetdevmacvlan.c +++ b/src/util/virnetdevmacvlan.c @@ -152,24 +152,24 @@ int virNetDevMacVLanDelete(const char *ifname) int virNetDevMacVLanTapOpen(const char *ifname, int *tapfd, - size_t tapfdSize) + size_t tapfdSize, + char **tapname) { int retries = 10; int ret = -1; int ifindex; size_t i = 0; - g_autofree char *tapname = NULL; if (virNetDevGetIndex(ifname, &ifindex) < 0) return -1; - tapname = g_strdup_printf("/dev/tap%d", ifindex); + *tapname = g_strdup_printf("/dev/tap%d", ifindex); for (i = 0; i < tapfdSize; i++) { int fd = -1; while (fd < 0) { - if ((fd = open(tapname, O_RDWR)) >= 0) { + if ((fd = open(*tapname, O_RDWR)) >= 0) { tapfd[i] = fd; } else if (retries-- > 0) { /* may need to wait for udev to be done */ @@ -178,7 +178,7 @@ virNetDevMacVLanTapOpen(const char *ifname, /* However, if haven't succeeded, quit. */ virReportSystemError(errno, _("cannot open macvtap tap device %1$s"), - tapname); + *tapname); goto cleanup; } } @@ -188,6 +188,7 @@ virNetDevMacVLanTapOpen(const char *ifname, cleanup: if (ret < 0) { + g_free(*tapname); while (i--) VIR_FORCE_CLOSE(tapfd[i]); } @@ -659,6 +660,7 @@ virNetDevMacVLanCreateWithVPortProfile(const char *ifnameRequested, char *stateDir, int *tapfd, size_t tapfdSize, + char **tapfdpath, unsigned int flags) { g_autofree char *ifname = NULL; @@ -729,7 +731,7 @@ virNetDevMacVLanCreateWithVPortProfile(const char *ifnameRequested, } if (flags & VIR_NETDEV_MACVLAN_CREATE_WITH_TAP) { - if (virNetDevMacVLanTapOpen(ifname, tapfd, tapfdSize) < 0) + if (virNetDevMacVLanTapOpen(ifname, tapfd, tapfdSize, tapfdpath) < 0) goto disassociate_exit; if (virNetDevMacVLanTapSetup(tapfd, tapfdSize, vnet_hdr) < 0) @@ -888,7 +890,8 @@ int virNetDevMacVLanDelete(const char *ifname G_GNUC_UNUSED) int virNetDevMacVLanTapOpen(const char *ifname G_GNUC_UNUSED, int *tapfd G_GNUC_UNUSED, - size_t tapfdSize G_GNUC_UNUSED) + size_t tapfdSize G_GNUC_UNUSED, + char **tapname G_GNUC_UNUSED) { virReportSystemError(ENOSYS, "%s", _("Cannot create macvlan devices on this platform")); @@ -917,6 +920,7 @@ int virNetDevMacVLanCreateWithVPortProfile(const char *ifname G_GNUC_UNUSED, char *stateDir G_GNUC_UNUSED, int *tapfd G_GNUC_UNUSED, size_t tapfdSize G_GNUC_UNUSED, + char **tapfdpath G_GNUC_UNUSED, unsigned int unused_flags G_GNUC_UNUSED) { virReportSystemError(ENOSYS, "%s", diff --git a/src/util/virnetdevmacvlan.h b/src/util/virnetdevmacvlan.h index 31e4804cdc0d7c4beb74ba66d204d0ff7ad83151..7424b8796529d6c6d1909eee81c88e8ded0ea84b 100644 --- a/src/util/virnetdevmacvlan.h +++ b/src/util/virnetdevmacvlan.h @@ -72,13 +72,15 @@ int virNetDevMacVLanCreateWithVPortProfile(const char *ifname, char *stateDir, int *tapfd, size_t tapfdSize, + char **tapfdpath, unsigned int flags) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(6) ATTRIBUTE_NONNULL(8) ATTRIBUTE_NONNULL(10) G_GNUC_WARN_UNUSED_RESULT; int virNetDevMacVLanTapOpen(const char *ifname, int *tapfd, - size_t tapfdSize) + size_t tapfdSize, + char **tapname) ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) G_GNUC_WARN_UNUSED_RESULT; --- base-commit: 74fc02d792f7ee55d2e0a7b9ad4e6d751c36ceb8 change-id: 20260105-apparmor-races-d03238ee4d93 Best regards, -- Wesley Hershberger <wesley.hershberger(a)canonical.com>

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Qemu pause-before-switchover and libvirt live migration
by Rogério Vinhal Nunes 03 Feb '26

03 Feb '26

Hello, I’m looking into the libvirt hooks that are available to make use of during a live migration, but there's only hooks on migration begin and migration end. On qemu directly I’m able to use pause-before-switchover migration capability to run a custom operation just before it moves to the destination, but within libvirt it seems that while this is leveraged internally, it’s not currently exposed to the client in a way I can use. Does anyone have any suggestions on how I could expose this to the client in a generic and sensible way? Thanks, Rogerio

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[PATCH 0/9] qemu: add support for block latency histogram collection
by Peter Krempa 03 Feb '26

03 Feb '26

This patchset introduces configuration of the block latency histogram feature in qemu as well as exposes the histograms via bulk domain stats. The feature was in qemu for a long time so no capabilities are needed. Peter Krempa (9): qemu: Extract disk setup done via QMP into a separate helper qemu: process: Rename 'qemuProcessSetupDiskThrottling' to 'qemuProcessSetupDisks' qemu: monitor: Extract block latency histogram stats into 'qemuBlockStats' Expose latency histograms via 'virConnectGetAllDomainStats' qemu: monitor: Add handlers for 'block-latency-histogram-set' docs: formatdomain: Fix indentation of docs for <disk><driver><statistics> element docs: formatdomain: Reword section about the '<statistics>' element under disk driver Introduce support for disk operation latency histogram collection qemu: Setup disk latency histograms on startup/hotplug/update docs/formatdomain.rst | 77 ++++++++-- docs/manpages/virsh.rst | 7 + include/libvirt/libvirt-domain.h | 113 +++++++++++++++ src/conf/domain_conf.c | 133 +++++++++++++++++- src/conf/domain_conf.h | 7 + src/conf/schemas/domaincommon.rng | 37 ++++- src/qemu/qemu_domain.c | 17 +++ src/qemu/qemu_domain.h | 3 + src/qemu/qemu_driver.c | 43 ++++++ src/qemu/qemu_hotplug.c | 52 ++++--- src/qemu/qemu_monitor.c | 41 ++++++ src/qemu/qemu_monitor.h | 27 ++++ src/qemu/qemu_monitor_json.c | 115 +++++++++++++++ src/qemu/qemu_monitor_json.h | 9 ++ src/qemu/qemu_process.c | 63 ++++++--- src/qemu/qemu_process.h | 3 + tests/qemumonitorjsontest.c | 9 ++ ...isk-statistics-intervals.x86_64-latest.xml | 29 ++++ .../disk-statistics-intervals.xml | 25 ++++ 19 files changed, 748 insertions(+), 62 deletions(-) -- 2.52.0

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[PATCH v6 0/7] qemu: Implement support for iommufd
by Nathan Chen 03 Feb '26

03 Feb '26

Hi, This is a follow up to the fifth patch series [0] for using iommufd to propagate DMA mappings to the kernel for VM-assigned host devices in a qemu VM. We add a new 'iommufd' attribute for hostdev devices to be associated with the iommufd object. For instance, specifying the iommufd object and associated hostdev in a VM definition: <devices> ... <hostdev mode='subsystem' type='pci' managed='no'> <driver iommufd='yes'/> <source> <address domain='0x0009' bus='0x01' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x15' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <driver iommufd='yes'/> <source> <address domain='0x0019' bus='0x01' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> ... </devices> This would get translated to a qemu command line with the arguments below. Note that libvirt will open the /dev/iommu and VFIO cdev, passing the associated fd number to qemu: -object '{"qom-type":"iommufd","id":"iommufd0","fd":"24"}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","iommufd":"iommufd0","fd":"22","bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","iommufd":"iommufd0","fd":"25","bus":"pci.22","addr":"0x0"}' \ Changes from v5: - Updated documentation to point to 12.1.0 (QEMU and KVM only) - Move define and VIR_LOG_INIT out of #ifdef __linux__ block in viriommufd.h - Remove unneeded virPCIDeviceFree() from AppArmorSetSecurityHostdevLabel - Always error out if per-process accounting failed Changes from v4: - Move qemuProcessOpenVfioFds() to qemu_process.h in patch 4/7 - Add `linux/iommufd.h` into headers list in the meson.build file - Correct viriommufd.c pre-processor definition indentations - Restore call to virIOMMUFDSetRLimitMode() in patch 5/7 - Fix indentations for various print function calls - Move the qemuProcessOpenVfioFds() call to qemuProcessPrepareHost() - Make qemuProcessOpenVfioFds() static - Remove unnecessary formatting and comment in virPCIDeviceGetVfioPath() - Clean up namespace and cgroup changes with conditional check for iommufd - Remove virIOMMUFDSupported() - Fix seclabel return logic - In Apparmor seclabel logic, use g_autoptr for virPCIDevice pointer Changes from v3: - Resolved issue from v2 where stale FD from previous VM boot was in use - Remove second approach for retrieving VFIO device path in virPCIDeviceGetVfioPath() - Resolve broken build of libvirt on non-Linux platforms - Conditionally define iommufd headers and use system headers where possible - Add non-fatal handling + warning print for EPERM for the IOMMU_OPTION_RLIMIT_MODE ioctl - Replace references to /dev/iommu with VIR_IOMMU_DEV_PATH - Implement virIOMMUFDSupported(void) to check for existence of /dev/iommu on host - Include tests for multiple hostdevs Changes from v2: - Set per-process memory accounting mode for iommufd - Separated out formatting of iommufd object from qemuBuildHostdevCommandLine - Placed hostdev private data implementation in a separate commit - Allocate hostdev private data unconditionally - Compare FDs against -1 - Integrated callback function in virQEMUDriverPrivateDataCallbacks for qemuDomainHostdevPrivateNew - Dropped qemuProcessCloseVfioFds - Addressed other feedback from v2 (formatting, includes, etc.) - Revised seclabel logic to be device-specific for AppArmor and to allow paths for SELinux/DAC This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/commits/iommufd-v6-01-26 Thanks, Nathan [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/GKSD… Nathan Chen (7): qemu: Implement support for associating iommufd to hostdev qemu: Introduce privateData for hostdevs qemu: Support per-process memory accounting for iommufd qemu: open VFIO FDs from libvirt backend qemu: open iommufd FD from libvirt backend qemu: Update Cgroup, namespace, and seclabel for iommufd tests: qemuxmlconfdata: provide iommufd sample XML and CLI args docs/formatdomain.rst | 6 + meson.build | 1 + po/POTFILES | 1 + src/bhyve/bhyve_parse_command.c | 2 +- src/conf/device_conf.c | 11 ++ src/conf/device_conf.h | 1 + src/conf/domain_conf.c | 13 +- src/conf/domain_conf.h | 5 +- src/conf/schemas/basictypes.rng | 5 + src/libvirt_private.syms | 4 + src/libxl/xen_common.c | 2 +- src/libxl/xen_xl.c | 2 +- src/lxc/lxc_native.c | 2 +- src/qemu/qemu_cgroup.c | 3 + src/qemu/qemu_command.c | 76 +++++++++++ src/qemu/qemu_domain.c | 41 ++++++ src/qemu/qemu_domain.h | 17 +++ src/qemu/qemu_namespace.c | 3 + src/qemu/qemu_process.c | 121 ++++++++++++++++++ src/security/security_apparmor.c | 28 ++-- src/security/security_dac.c | 49 +++++-- src/security/security_selinux.c | 47 +++++-- src/security/virt-aa-helper.c | 33 ++++- src/util/meson.build | 1 + src/util/viriommufd.c | 111 ++++++++++++++++ src/util/viriommufd.h | 25 ++++ src/util/virpci.c | 39 ++++++ src/util/virpci.h | 2 + src/vbox/vbox_common.c | 2 +- .../iommufd-q35.x86_64-latest.args | 41 ++++++ .../iommufd-q35.x86_64-latest.xml | 60 +++++++++ tests/qemuxmlconfdata/iommufd-q35.xml | 38 ++++++ ...fd-virt-pci-bus-single.aarch64-latest.args | 32 +++++ ...ufd-virt-pci-bus-single.aarch64-latest.xml | 31 +++++ .../iommufd-virt-pci-bus-single.xml | 22 ++++ .../iommufd-virt.aarch64-latest.args | 36 ++++++ .../iommufd-virt.aarch64-latest.xml | 53 ++++++++ tests/qemuxmlconfdata/iommufd-virt.xml | 29 +++++ .../iommufd.x86_64-latest.args | 35 +++++ .../qemuxmlconfdata/iommufd.x86_64-latest.xml | 38 ++++++ tests/qemuxmlconfdata/iommufd.xml | 30 +++++ tests/qemuxmlconftest.c | 34 +++++ tests/virhostdevtest.c | 2 +- 43 files changed, 1090 insertions(+), 44 deletions(-) create mode 100644 src/util/viriommufd.c create mode 100644 src/util/viriommufd.h create mode 100644 tests/qemuxmlconfdata/iommufd-q35.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-q35.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-q35.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt-pci-bus-single.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-virt-pci-bus-single.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt-pci-bus-single.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-virt.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt.xml create mode 100644 tests/qemuxmlconfdata/iommufd.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd.xml -- 2.43.0

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[PATCH v2 0/2] Adding support for client-based FD migrations.
by Tejus GK 02 Feb '26

02 Feb '26

Libvirt supports FD-based live migrations in the form of tunnelled migrations. However, this isn't as performant as of now, since it involves extra copies.· This patchset proposes adding support for externally provided file descriptors for live migration. By allowing the client to supply the migration FD directly, the extra copy can be avoided, improving overall migration performance. The intent is to gather early feedback on the approach and its feasibility. Comments, concerns, and suggestions are very welcome :) V2: 1. Removed the approach of introducing a new FD passing API and instead reuse the virDomainFDAssociate API along with a dummy VM on the destination host. 2. Introduced a new virDomainMigrate parameter, VIR_MIGRATE_PARAM_FD_SET. Tejus GK (2): qemu: support incoming "fd" uri qemu: add support for fd based live migrations include/libvirt/libvirt-domain.h | 14 +++ src/qemu/qemu_driver.c | 24 +++-- src/qemu/qemu_migration.c | 174 +++++++++++++++++++++++++------ src/qemu/qemu_migration.h | 3 + 4 files changed, 178 insertions(+), 37 deletions(-) -- 2.43.7

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[PATCH 0/2] target/arm: Deprecate '-cpu any'
by Philippe Mathieu-Daudé 02 Feb '26

02 Feb '26

Arm '-cpu any' is aliased to '-cpu max' since more than 5 years. Deprecate the former in preparation of removal. Philippe Mathieu-Daudé (2): target/arm: Remove dead code target/arm: Deprecate '-cpu any' (remplaced by '-cpu max') docs/about/deprecated.rst | 8 ++++++++ target/arm/cpu.c | 1 + target/arm/tcg/cpu32.c | 3 --- 3 files changed, 9 insertions(+), 3 deletions(-) -- 2.52.0

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[PATCH v7 0/2] qemu: Support accelerated vSMMUs
by Nathan Chen 31 Jan '26

31 Jan '26

Hi, This is a follow up to the sixth RFC patchset [0] for supporting multiple accelerated vSMMU instances. Support for user-creatable accelerated SMMUv3 in QEMU has been applied to target-arm.next [1]. For instance, specifying hostdevs associated with multiple accelerated SMMUs, configured to be routed to pcie-expander-bus controllers in a way where VFIO device to SMMUv3 associations are matched with the host: <devices> ... <controller type='pci' index='1' model='pcie-expander-bus'> <model name='pxb-pcie'/> <target busNr='252'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/> </controller> <controller type='pci' index='2' model='pcie-expander-bus'> <model name='pxb-pcie'/> <target busNr='248'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </controller> ... <controller type='pci' index='21' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='21' port='0x0'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </controller> <controller type='pci' index='22' model='pcie-root-port'> <model name='pcie-root-port'/> <target chassis='22' port='0xa8'/> <address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/> </controller> ... <hostdev mode='subsystem' type='pci' managed='no'> <source> <address domain='0x0009' bus='0x01' slot='0x00' function='0x0'/> </source> <vpasidCapOffset>0xff8</vpasidCapOffset> <address type='pci' domain='0x0000' bus='0x15' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <source> <address domain='0x0019' bus='0x01' slot='0x00' function='0x0'/> </source> <vpasidCapOffset>0xff8</vpasidCapOffset> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> <iommu model='smmuv3'> <driver parentIdx='1' accel='on' ats='on' ril='off' ssidSize='20' oas='44'/> </iommu> <iommu model='smmuv3'> <driver parentIdx='2' accel='on' ats='on' ril='off' ssidSize='20' oas='44'/> </iommu> </devices> This would get translated to a qemu command line with the arguments below: -device '{"driver":"pxb-pcie","bus_nr":252,"id":"pci.1","bus":"pcie.0","addr":"0x1"}' \ -device '{"driver":"pxb-pcie","bus_nr":248,"id":"pci.2","bus":"pcie.0","addr":"0x2"}' \ -device '{"driver":"pcie-root-port","port":0,"chassis":21,"id":"pci.21","bus":"pci.1","addr":"0x0"}' \ -device '{"driver":"pcie-root-port","port":168,"chassis":22,"id":"pci.22","bus":"pci.2","addr":"0x0"}' \ -device '{"driver":"arm-smmuv3","primary-bus":"pci.1","id":"iommu0","accel":true,"ats":true,"ril":false,"ssidsize":20,"oas":44}' \ -device '{"driver":"arm-smmuv3","primary-bus":"pci.2","id":"iommu1","accel":true,"ats":true,"ril":false,"ssidsize":20,"oas":44}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","x-vpasid-cap-offset":4088,"bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","x-vpasid-cap-offset":4088,"bus":"pci.22","addr":"0x0"}' \ This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/tree/smmuv3-accel-01-26-v7/ Thanks, Nathan Changes from v6: - Remove smmuv3 'pasid' attribute - Add smmuv3 'ssidsize' attribute - Add support for 'vpasidCapOffset' element - Modify logic for building accel smmuv3 qemu command line to omit ATS, RIL, accel flags when not needed (enabled/disabled by default in QEMU SMMUv3) [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/VRSS… [1] https://lore.kernel.org/qemu-devel/20260126104342.253965-1-skolothumtho@nvi… Nathan Chen (2): qemu: Add support for HW-accelerated nested SMMUv3 tests: qemuxmlconfdata: provide HW-accel smmuv3 sample XML and CLI args docs/formatdomain.rst | 36 +++++++ src/conf/domain_conf.c | 101 +++++++++++++++++- src/conf/domain_conf.h | 6 ++ src/conf/domain_validate.c | 36 ++++++- src/conf/schemas/domaincommon.rng | 32 ++++++ src/qemu/qemu_command.c | 23 ++++ src/util/virpci.h | 4 + ...u-smmuv3-pci-bus-accel.aarch64-latest.args | 38 +++++++ ...mu-smmuv3-pci-bus-accel.aarch64-latest.xml | 64 +++++++++++ .../iommu-smmuv3-pci-bus-accel.xml | 54 ++++++++++ tests/qemuxmlconftest.c | 1 + 11 files changed, 390 insertions(+), 5 deletions(-) create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommu-smmuv3-pci-bus-accel.xml -- 2.43.0

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[PATCH v5 0/7] qemu: Implement support for iommufd
by Nathan Chen 31 Jan '26

31 Jan '26

Hi, This is a follow up to the fourth patch series [0] for using iommufd to propagate DMA mappings to the kernel for VM-assigned host devices in a qemu VM. We add a new 'iommufd' attribute for hostdev devices to be associated with the iommufd object. For instance, specifying the iommufd object and associated hostdev in a VM definition: <devices> ... <hostdev mode='subsystem' type='pci' managed='no'> <driver iommufd='yes'/> <source> <address domain='0x0009' bus='0x01' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x15' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <driver iommufd='yes'/> <source> <address domain='0x0019' bus='0x01' slot='0x00' function='0x0'/> </source> <address type='pci' domain='0x0000' bus='0x16' slot='0x00' function='0x0'/> </hostdev> ... </devices> This would get translated to a qemu command line with the arguments below. Note that libvirt will open the /dev/iommu and VFIO cdev, passing the associated fd number to qemu: -object '{"qom-type":"iommufd","id":"iommufd0","fd":"24"}' \ -device '{"driver":"vfio-pci","host":"0009:01:00.0","id":"hostdev0","iommufd":"iommufd0","fd":"22","bus":"pci.21","addr":"0x0"}' \ -device '{"driver":"vfio-pci","host":"0019:01:00.0","id":"hostdev1","iommufd":"iommufd0","fd":"25","bus":"pci.22","addr":"0x0"}' \ Changes from v4: - Move qemuProcessOpenVfioFds() to qemu_process.h in patch 4/7 - Add `linux/iommufd.h` into headers list in the meson.build file - Correct viriommufd.c pre-processor definition indentations - Restore call to virIOMMUFDSetRLimitMode() in patch 5/7 - Fix indentations for various print function calls - Move the qemuProcessOpenVfioFds() call to qemuProcessPrepareHost() - Make qemuProcessOpenVfioFds() static - Remove unnecessary formatting and comment in virPCIDeviceGetVfioPath() - Clean up namespace and cgroup changes with conditional check for iommufd - Remove virIOMMUFDSupported() - Fix seclabel return logic - In Apparmor seclabel logic, use g_autoptr for virPCIDevice pointer Changes from v3: - Resolved issue from v2 where stale FD from previous VM boot was in use - Remove second approach for retrieving VFIO device path in virPCIDeviceGetVfioPath() - Resolve broken build of libvirt on non-Linux platforms - Conditionally define iommufd headers and use system headers where possible - Add non-fatal handling + warning print for EPERM for the IOMMU_OPTION_RLIMIT_MODE ioctl - Replace references to /dev/iommu with VIR_IOMMU_DEV_PATH - Implement virIOMMUFDSupported(void) to check for existence of /dev/iommu on host - Include tests for multiple hostdevs Changes from v2: - Set per-process memory accounting mode for iommufd - Separated out formatting of iommufd object from qemuBuildHostdevCommandLine - Placed hostdev private data implementation in a separate commit - Allocate hostdev private data unconditionally - Compare FDs against -1 - Integrated callback function in virQEMUDriverPrivateDataCallbacks for qemuDomainHostdevPrivateNew - Dropped qemuProcessCloseVfioFds - Addressed other feedback from v2 (formatting, includes, etc.) - Revised seclabel logic to be device-specific for AppArmor and to allow paths for SELinux/DAC This series is on Github: https://github.com/NathanChenNVIDIA/libvirt/commits/iommufd-v5-01-26 Thanks, Nathan [0] https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/thread/4BEU… Nathan Chen (7): qemu: Implement support for associating iommufd to hostdev qemu: Introduce privateData for hostdevs qemu: Support per-process memory accounting for iommufd qemu: open VFIO FDs from libvirt backend qemu: open iommufd FD from libvirt backend qemu: Update Cgroup, namespace, and seclabel for iommufd tests: qemuxmlconfdata: provide iommufd sample XML and CLI args docs/formatdomain.rst | 7 + meson.build | 1 + po/POTFILES | 1 + src/bhyve/bhyve_parse_command.c | 2 +- src/conf/device_conf.c | 11 ++ src/conf/device_conf.h | 1 + src/conf/domain_conf.c | 13 +- src/conf/domain_conf.h | 5 +- src/conf/schemas/basictypes.rng | 5 + src/libvirt_private.syms | 4 + src/libxl/xen_common.c | 2 +- src/libxl/xen_xl.c | 2 +- src/lxc/lxc_native.c | 2 +- src/qemu/qemu_cgroup.c | 3 + src/qemu/qemu_command.c | 76 +++++++++++ src/qemu/qemu_domain.c | 41 ++++++ src/qemu/qemu_domain.h | 17 +++ src/qemu/qemu_namespace.c | 3 + src/qemu/qemu_process.c | 121 ++++++++++++++++++ src/security/security_apparmor.c | 31 +++-- src/security/security_dac.c | 49 +++++-- src/security/security_selinux.c | 47 +++++-- src/security/virt-aa-helper.c | 33 ++++- src/util/meson.build | 1 + src/util/viriommufd.c | 111 ++++++++++++++++ src/util/viriommufd.h | 25 ++++ src/util/virpci.c | 39 ++++++ src/util/virpci.h | 2 + src/vbox/vbox_common.c | 2 +- .../iommufd-q35.x86_64-latest.args | 41 ++++++ .../iommufd-q35.x86_64-latest.xml | 60 +++++++++ tests/qemuxmlconfdata/iommufd-q35.xml | 38 ++++++ ...fd-virt-pci-bus-single.aarch64-latest.args | 32 +++++ ...ufd-virt-pci-bus-single.aarch64-latest.xml | 31 +++++ .../iommufd-virt-pci-bus-single.xml | 22 ++++ .../iommufd-virt.aarch64-latest.args | 36 ++++++ .../iommufd-virt.aarch64-latest.xml | 53 ++++++++ tests/qemuxmlconfdata/iommufd-virt.xml | 29 +++++ .../iommufd.x86_64-latest.args | 35 +++++ .../qemuxmlconfdata/iommufd.x86_64-latest.xml | 38 ++++++ tests/qemuxmlconfdata/iommufd.xml | 30 +++++ tests/qemuxmlconftest.c | 34 +++++ tests/virhostdevtest.c | 2 +- 43 files changed, 1093 insertions(+), 45 deletions(-) create mode 100644 src/util/viriommufd.c create mode 100644 src/util/viriommufd.h create mode 100644 tests/qemuxmlconfdata/iommufd-q35.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-q35.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-q35.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt-pci-bus-single.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-virt-pci-bus-single.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt-pci-bus-single.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt.aarch64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd-virt.aarch64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd-virt.xml create mode 100644 tests/qemuxmlconfdata/iommufd.x86_64-latest.args create mode 100644 tests/qemuxmlconfdata/iommufd.x86_64-latest.xml create mode 100644 tests/qemuxmlconfdata/iommufd.xml -- 2.43.0

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[PATCH] qapi/net: deprecate TAP fd and vhostfd options
by Vladimir Sementsov-Ogievskiy 31 Jan '26

31 Jan '26

They are the same as fds and vhostfds, except they accept only one fd. Let's deprecate redundant options. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru> --- Hi all! after "[PATCH v2 00/12] net: refactoring and fixes" options fd and vhostfd becomes redundant, fds and vhostfds may be used instead. this patch also based on "[PATCH v6] qapi: net: deprecate vhostforce option", that's why it's sent separately. Based-on: <20260129213215.1405459-1-vsementsov(a)yandex-team.ru> Based-on: <20251113071711.349651-1-vsementsov(a)yandex-team.ru> docs/about/deprecated.rst | 6 ++++++ qapi/net.json | 9 +++++---- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index e8ff478583..9010f8ab07 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -451,6 +451,12 @@ TAP ``vhostforce`` (since 11.0) The ``vhostforce`` option is redundant with the ``vhost`` option. If they conflict, ``vhost`` takes precedence. Just use ``vhost``. +TAP ``fd`` and ``vhostfd`` (since 11.0) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Use ``fds`` and ``vhostfds`` correspondingly, each set with one fd +instead of ``fd`` and ``vhsotfd``. + Vhost-user ``vhostforce`` (since 11.0) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/qapi/net.json b/qapi/net.json index 9a00d578e9..2d5aed3ef8 100644 --- a/qapi/net.json +++ b/qapi/net.json @@ -326,8 +326,7 @@ # # @fd: file descriptor of an already opened tap # -# @fds: multiple file descriptors of already opened multiqueue capable -# tap +# @fds: multiple file descriptors of already opened tap # # @script: script to initialize the interface # @@ -359,13 +358,15 @@ # Features: # # @deprecated: Member @vhostforce is deprecated. Use @vhost instead. +# Member @fd is deprecated. Use @fds instead. +# Member @vhostfd is deprecated. Use @vhostfds instead. # # Since: 1.2 ## { 'struct': 'NetdevTapOptions', 'data': { '*ifname': 'str', - '*fd': 'str', + '*fd': { 'type': 'str', 'features': [ 'deprecated' ] }, '*fds': 'str', '*script': 'str', '*downscript': 'str', @@ -374,7 +375,7 @@ '*sndbuf': 'size', '*vnet_hdr': 'bool', '*vhost': 'bool', - '*vhostfd': 'str', + '*vhostfd': { 'type': 'str', 'features': [ 'deprecated' ] }, '*vhostfds': 'str', '*vhostforce': { 'type': 'bool', 'features': [ 'deprecated' ] }, '*queues': 'uint32', -- 2.52.0

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[PATCH] networkxmlconftest: Expect success for "hostdev" case only on Linux
by Michal Privoznik 31 Jan '26

31 Jan '26

From: Michal Privoznik <mprivozn(a)redhat.com> Our network has multiple means of forwarding the traffic and 'hostdev' is one of them. This mode means that the network is configured to use a set of PCI devices which are then assigned to individual domains to use (PCI device assignment). Now, as of v12.0.0-61-gecb2e06bdf our test runners (testCompareXMLToXMLFiles() and testCompareXMLToConfFiles()) call networkValidateTests(). For aforementioned type of network this means checking that the specified set of devices contains only VFs (see v3.2.0-rc1~24 for more info). It is true that our virpcimock is preloaded which mimics VFs, but our utils module (virpci.c specifically) talks to sysfs to check various PCI device attributes, including whether it's a VF. This obviously works on Linux and doesn't work anywhere else. Therefore, until our utils module is taught how to check PCI attribs on other systems, make the "hostdev" test case expect validation failure on non-Linux systems. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com> --- tests/networkxmlconftest.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tests/networkxmlconftest.c b/tests/networkxmlconftest.c index b32a39c553..b74d5b14f5 100644 --- a/tests/networkxmlconftest.c +++ b/tests/networkxmlconftest.c @@ -313,7 +313,16 @@ mymain(void) DO_TEST("bandwidth-network"); DO_TEST("openvswitch-net"); DO_TEST_VALIDATE_ERROR("passthrough-pf"); +#ifdef __linux__ DO_TEST("hostdev"); +#else + /* Our test runners call networkValidateTests() which for + * <forward mode='hostdev'/> means validating that PCI + * devices are VFs. It's done so by querying sysfs which + * obviously works on Linux only. Thus, expect a validation + * error elsewhere. */ + DO_TEST_VALIDATE_ERROR("hostdev"); +#endif DO_TEST_FLAGS("hostdev-pf", VIR_NETWORK_XML_INACTIVE); DO_TEST_FLAGS("hostdev-pf-driver-model", VIR_NETWORK_XML_INACTIVE); DO_TEST("ptr-domains-auto"); -- 2.52.0

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