From nobody Fri Jan 12 09:19:24 2024 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4TBGFV165xz56RCj; Fri, 12 Jan 2024 09:19:26 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4TBGFV0f6Sz4ZR2; Fri, 12 Jan 2024 09:19:26 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1705051166; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=THRHnvpUozlYk2NQh/qi0Qf2r6UrpPGijv3BTy/8c9w=; b=hmyIdEHS4HD6H8UE2+/GMPOW9ZNGxLntyrzchC9kzNcb9KPpUjyRa1K08MvlHWUxr5CMJc UAokLrgNGzoAPdtWEAb80RlevgBpz8G/VhY6kifaccS4qed6OxscADayZz8mSD1WOznfob jvV3yrcRKWjuQ0JZt+j5XLVkN4o+tDi/RwNGJ+9pZhNh5gXaYm+/jO8YIU3wWPv7Al9Izf WjNvHKBoF0iJGRQPpzA3KHnUUvx52uYVPI0TGj1mSq4MITucBHabcuQ5MWXx90H4ynmnc1 O7SS0/w7MftCsZzS/eW/ynrhNiIXwKl4K3cqeyAhq70UMXPq86yM377hLaYUKQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1705051166; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=THRHnvpUozlYk2NQh/qi0Qf2r6UrpPGijv3BTy/8c9w=; b=G0nKy3aoJQ3YxelF7XfcsCxPmz73jYNwdFaoLiLpCiYY9aLBk72nKHNFdy1uiKZeuxmoRg WBGUMh8eFrabPfNpxDpcBlODCSkrm1xxJigUgJGzH7jdxM+zmkbXVmpBb5B/4YMFLmhm+/ +GtsQKQOFjIHMPKMIQGc4D7xy6jEa+PI3pJ4u69YIg2oGhN5ZRv8CJb2j5oyykEZ62r31r +3c8DemFF8D4gUbQ7/9FWLhtUQgLHMJdWMFY4ECbUh+I82lFKV2SK284yjOzB+i3mblN3f Taoa3SucL//L/3QDSZ7uynv8jshc+6IeasUFmrEHfN4wiMmX05lvL4raJLEVBg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1705051166; a=rsa-sha256; cv=none; b=W0yz7qyCrJDPVKSnnMZo1RUE+lLLuSAAZo9KIgiY9UCtdSd4kpkjS0C0t6nMyjlQjQ7KPe fhp22Ojt+Chdvyn7dHn/3zvIa4Vk0Ma5Bq+uRN4wC1bmjTNwmnHPKXT0rIGLKt/iQKlhmo qMX2GvZ9Kcbmob+of9WgpFZ6/4q0ECOpXC+SXnR4nnf/UllMIKugv4WSVjUcT9yC6IEslK KbiBLN/eSKKjKKAvaofwHkaxrV49rh4aDM1dSvcL3/H8Q8mmEjUty7a9tjxHsQ5bNCaK81 X4JIRV3438qXFMU8UuC11//E/VCyKT75RUpwDvESlbcqyQriaYWdK20yjNBLTA== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4TBGFT6m21zwWp; Fri, 12 Jan 2024 09:19:25 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.17.1/8.17.1) with ESMTP id 40C9JObq020172; Fri, 12 Jan 2024 09:19:24 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.17.1/8.17.1/Submit) id 40C9JO0n020169; Fri, 12 Jan 2024 09:19:24 GMT (envelope-from git) Date: Fri, 12 Jan 2024 09:19:24 GMT Message-Id: <202401120919.40C9JO0n020169@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Roger Pau =?utf-8?Q?Monn=C3=A9?= Subject: git: 82126ef92fdb - main - xen: improve man (4) page List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: royger X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 82126ef92fdb3c13a67ad44d33c0fe6ea479c01a Auto-Submitted: auto-generated The branch main has been updated by royger: URL: https://cgit.FreeBSD.org/src/commit/?id=82126ef92fdb3c13a67ad44d33c0fe6ea479c01a commit 82126ef92fdb3c13a67ad44d33c0fe6ea479c01a Author: Roger Pau Monné AuthorDate: 2024-01-09 09:26:06 +0000 Commit: Roger Pau Monné CommitDate: 2024-01-12 09:18:49 +0000 xen: improve man (4) page Update the xen(4) man page to reflect the current support status. Reported by: kevans Reviewed by: bcr kevans imp Differential revision: https://reviews.freebsd.org/D43373 --- share/man/man4/xen.4 | 74 +++++++++++++++++++++++----------------------------- 1 file changed, 33 insertions(+), 41 deletions(-) diff --git a/share/man/man4/xen.4 b/share/man/man4/xen.4 index 6660ab3c268b..15312866dae6 100644 --- a/share/man/man4/xen.4 +++ b/share/man/man4/xen.4 @@ -26,19 +26,19 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd April 30, 2015 +.Dd January 8, 2024 .Dt XEN 4 .Os .Sh NAME .Nm xen -.Nd Xen Hypervisor Guest (DomU) Support +.Nd Xen Hypervisor Support .Sh SYNOPSIS -To compile hardware-assisted virtualization (HVM) Xen guest support with -para-virtualized drivers into an amd64 or i386 kernel, -place the following lines in your kernel configuration file: -.Bd -ragged -offset indent -.Cd "options XENHVM" -.Cd "device xenpci" +FreeBSD supports running both as a Xen guest and host on amd64 hardware. +Guest support is limited to HVM and PVH modes, while host support is limited to +PVH mode only. +.Pp +Xen support is built by default in the i386 and amd64 GENERIC kernels; note +however that host mode is only available on amd64. .Ed .Sh DESCRIPTION The Xen Hypervisor allows multiple virtual machines to be run on a single @@ -52,20 +52,18 @@ to access resources such as virtual network interfaces and disk devices. .Pp With later instruction set extensions from AMD and Intel to support fully virtualizable instructions, unmodified virtual memory systems can also be -supported; this is referred to as hardware-assisted virtualization (HVM). +supported; this is referred to as hardware-assisted virtualization (HVM and PVH). HVM configurations may either rely on transparently emulated hardware peripherals, or para-virtualized drivers, which are aware of virtualization, and hence able to optimize certain behaviors to improve performance or semantics. +PVH configurations rely on para-virtualized drivers exclusively for IO. .Pp .Fx -supports hardware-assisted virtualization (HVM) on both i386 and amd64 -kernels. -.Pp Para-virtualized device drivers are required in order to support certain functionality, such as processing management requests, returning idle physical memory pages to the hypervisor, etc. -.Ss Xen DomU device drivers +.Ss Xen device drivers These para-virtualized drivers are supported: .Bl -hang -offset indent -width blkfront .It Nm balloon @@ -87,6 +85,10 @@ suspend, crash, and halt requests. Expose Xen events via the .Pa /dev/xen/evtchn special device. +.It Nm gntdev +Allow access to the grant table interface via the +.Pa /dev/xen/gntdev +special device. .It Nm netback Export local network interfaces to other Xen domains where they can be imported via @@ -94,35 +96,30 @@ imported via .It Nm netfront Import network interfaces from other Xen domains as local network interfaces, which may be used for IPv4, IPv6, etc. -.It Nm pcifront -Allow physical PCI devices to be passed through into a PV domain. +.It Nm privcmd +Allow issuing hypercalls via the +.Pa /dev/xen/privcmd +special device. +.It Nm timer +Implementation of a one-shot high resolution per-CPU timer using the hypercall +interface. +.It Nm acpi cpu +When running as a host forwards power management related information from ACPI +to the hypervisor for better performance management. .It Nm xenpci Represents the Xen PCI device, an emulated PCI device that is exposed to HVM domains. This device allows detection of the Xen hypervisor, and provides interrupt and shared memory services required to interact with the hypervisor. +.It Nm xenstore +Information storage space shared between domains. .El -.Ss Performance considerations -In general, PV drivers will perform better than emulated hardware, and are -the recommended configuration for HVM installations. -.Pp -Using a hypervisor introduces a second layer of scheduling that may limit the -effectiveness of certain -.Fx -scheduling optimisations. -Among these is adaptive locking, which is no longer able to determine whether -a thread holding a lock is in execution. -It is recommended that adaptive locking be disabled when using Xen: -.Bd -unfilled -offset indent -.Cd "options NO_ADAPTIVE_MUTEXES" -.Cd "options NO_ADAPTIVE_RWLOCKS" -.Cd "options NO_ADAPTIVE_SX" -.Ed .Sh HISTORY Support for .Nm first appeared in .Fx 8.1 . +Support for host mode was added in 11.0 . .Sh AUTHORS .An -nosplit .Fx @@ -133,15 +130,10 @@ and Further refinements were made by .An Justin Gibbs Aq Mt gibbs@FreeBSD.org , .An Adrian Chadd Aq Mt adrian@FreeBSD.org , +.An Colin Percival Aq Mt cperciva@FreeBSD.org , and -.An Colin Percival Aq Mt cperciva@FreeBSD.org . +.An Roger Pau Monné Aq Mt royger@FreeBSD.org . This manual page was written by -.An Robert Watson Aq Mt rwatson@FreeBSD.org . -.Sh BUGS -.Fx -is only able to run as a Xen guest (DomU) and not as a Xen host (Dom0). -.Pp -As of this release, Xen PV DomU support is not heavily tested; instability -has been reported during VM migration of PV kernels. -.Pp -Certain PV driver features, such as the balloon driver, are under-exercised. +.An Robert Watson Aq Mt rwatson@FreeBSD.org , +and +.An Roger Pau Monné Aq Mt royger@FreeBSD.org .