Date: Sun, 26 Apr 2026 09:22:10 +0000 From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Cc: Timo =?utf-8?Q?V=C3=B6lker?= <timo.voelker@fh-muenster.de> Subject: git: 32f8c7821394 - stable/14 - virtio: add loader tunables to sysctl Message-ID: <69edd942.38c08.5c5d6f7@gitrepo.freebsd.org>
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The branch stable/14 has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=32f8c7821394b3be2d97641dbe8bf8962e2bb90a commit 32f8c7821394b3be2d97641dbe8bf8962e2bb90a Author: Timo Völker <timo.voelker@fh-muenster.de> AuthorDate: 2026-03-02 18:15:37 +0000 Commit: Michael Tuexen <tuexen@FreeBSD.org> CommitDate: 2026-04-26 07:20:41 +0000 virtio: add loader tunables to sysctl virtio_pci uses two loader tunables that should be more visible. This patch adds these loader tunables to sysctl and describes them in the virtio(4) man page. Reviewed by: imp (erlier version), tuexen Differential Revision: https://reviews.freebsd.org/D55533 Event: Wiesbaden Hackathon 2026 (cherry picked from commit c70755bc0d8f703dbaa1520c15e8213a95847dd5) --- share/man/man4/virtio.4 | 28 ++++++++++++++++++++++++++-- sys/dev/virtio/pci/virtio_pci.c | 7 ++++++- sys/dev/virtio/pci/virtio_pci_modern.c | 7 ++++++- sys/dev/virtio/virtio.c | 4 ++++ 4 files changed, 42 insertions(+), 4 deletions(-) diff --git a/share/man/man4/virtio.4 b/share/man/man4/virtio.4 index 1e5ea0e4a7da..0598d5d8621d 100644 --- a/share/man/man4/virtio.4 +++ b/share/man/man4/virtio.4 @@ -22,7 +22,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd May 26, 2019 +.Dd March 2, 2026 .Dt VIRTIO 4 .Os .Sh NAME @@ -54,7 +54,7 @@ The .Nm module provides a shared memory transport called a virtqueue. The -.Xr virtio_pci +.Sy virtio_pci device driver represents an emulated PCI device that the hypervisor makes available to the VM. This device provides the probing, configuration, and @@ -92,6 +92,30 @@ An emulated SCSI HBA is provided by the .Xr virtio_scsi 4 device driver. .El +.Sh LOADER TUNABLES +Tunables can be set at the +.Xr loader 8 +prompt before booting the kernel or stored in +.Xr loader.conf 5 . +.Bl -tag -width "hw.virtio.pci.transitional" +.It Va hw.virtio.pci.disable_msix +If set to 1, disables MSI-X. +The default value is 0. +.It Va hw.virtio.pci.transitional +For a transitional +.Nm +device, this tunable specifies whether to negotiate +modern mode and use the modern +.Nm +driver +.Pq 1 +or to negotiate legacy mode and +use the legacy +.Nm +driver +.Pq 1 . +The default value is 0. +.El .Sh SEE ALSO .Xr virtio_balloon 4 , .Xr virtio_blk 4 , diff --git a/sys/dev/virtio/pci/virtio_pci.c b/sys/dev/virtio/pci/virtio_pci.c index 4849affae58c..451a93d11759 100644 --- a/sys/dev/virtio/pci/virtio_pci.c +++ b/sys/dev/virtio/pci/virtio_pci.c @@ -98,8 +98,13 @@ MODULE_VERSION(virtio_pci, 1); MODULE_DEPEND(virtio_pci, pci, 1, 1, 1); MODULE_DEPEND(virtio_pci, virtio, 1, 1, 1); +SYSCTL_DECL(_hw_virtio); +SYSCTL_NODE(_hw_virtio, OID_AUTO, pci, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, + "VirtIO PCI driver parameters"); + int vtpci_disable_msix = 0; -TUNABLE_INT("hw.virtio.pci.disable_msix", &vtpci_disable_msix); +SYSCTL_INT(_hw_virtio_pci, OID_AUTO, disable_msix, CTLFLAG_RDTUN, + &vtpci_disable_msix, 0, "If set to 1, disables MSI-X."); static uint8_t vtpci_read_isr(struct vtpci_common *cn) diff --git a/sys/dev/virtio/pci/virtio_pci_modern.c b/sys/dev/virtio/pci/virtio_pci_modern.c index 2e59448b4b5e..2c54288aefba 100644 --- a/sys/dev/virtio/pci/virtio_pci_modern.c +++ b/sys/dev/virtio/pci/virtio_pci_modern.c @@ -34,6 +34,7 @@ #include <sys/bus.h> #include <sys/lock.h> #include <sys/kernel.h> +#include <sys/sysctl.h> #include <sys/module.h> #include <machine/bus.h> @@ -189,8 +190,12 @@ static void vtpci_modern_write_device_8(struct vtpci_modern_softc *, bus_size_t, uint64_t); /* Tunables. */ +SYSCTL_DECL(_hw_virtio_pci); + static int vtpci_modern_transitional = 0; -TUNABLE_INT("hw.virtio.pci.transitional", &vtpci_modern_transitional); +SYSCTL_INT(_hw_virtio_pci, OID_AUTO, transitional, CTLFLAG_RDTUN, + &vtpci_modern_transitional, 0, + "If 0, a transitional VirtIO device is used in legacy mode; otherwise, in modern mode."); static device_method_t vtpci_modern_methods[] = { /* Device interface. */ diff --git a/sys/dev/virtio/virtio.c b/sys/dev/virtio/virtio.c index 0637e0299333..14dad88b3f6d 100644 --- a/sys/dev/virtio/virtio.c +++ b/sys/dev/virtio/virtio.c @@ -31,6 +31,7 @@ #include <sys/systm.h> #include <sys/kernel.h> #include <sys/malloc.h> +#include <sys/sysctl.h> #include <sys/module.h> #include <sys/sbuf.h> @@ -84,6 +85,9 @@ static struct virtio_feature_desc virtio_common_feature_desc[] = { { 0, NULL } }; +SYSCTL_NODE(_hw, OID_AUTO, virtio, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, + "VirtIO driver parameters"); + const char * virtio_device_name(uint16_t devid) {home | help
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