linux-kernel - RE: [PATCH 07/13] x86/kconfig/64: Enable more virtualization guest options in the defconfig: enable Xen, Xen_PVH, Jailhouse, ACRN, Intel TDX and Hyper-V

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:
 <SN6PR02MB4157DAB3E543F77B72167721D476A@SN6PR02MB4157.namprd02.prod.outlook.com>
Date: Sat, 14 Jun 2025 16:46:23 +0000
From: Michael Kelley <mhklinux@...look.com>
To: Peter Zijlstra <peterz@...radead.org>
CC: Ingo Molnar <mingo@...nel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Vitaly Kuznetsov <vkuznets@...hat.com>, "H .
 Peter Anvin" <hpa@...or.com>, Linus Torvalds <torvalds@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>, Thomas Gleixner <tglx@...utronix.de>,
	Jürgen Groß <jgross@...e.com>, "Kirill A . Shutemov"
	<kirill.shutemov@...ux.intel.com>, Ard Biesheuvel <ardb@...nel.org>, Arnd
 Bergmann <arnd@...db.de>, Carlos Bilbao <carlos.bilbao@...nel.org>, David
 Woodhouse <dwmw@...zon.co.uk>, Elena Reshetova <elena.reshetova@...el.com>,
	Fei Li <fei1.li@...el.com>, Jan Kiszka <jan.kiszka@...mens.com>, Masahiro
 Yamada <yamada.masahiro@...ionext.com>, Michal Marek
	<michal.lkml@...kovi.net>, Paolo Bonzini <pbonzini@...hat.com>, Sean
 Christopherson <seanjc@...gle.com>, Stefano Stabellini
	<sstabellini@...nel.org>
Subject: RE: [PATCH 07/13] x86/kconfig/64: Enable more virtualization guest
 options in the defconfig: enable Xen, Xen_PVH, Jailhouse, ACRN, Intel TDX and
 Hyper-V

From: Peter Zijlstra <peterz@...radead.org> Sent: Saturday, June 14, 2025 3:31 AM
> 
> On Thu, May 15, 2025 at 11:40:06PM +0000, Michael Kelley wrote:
> > From: Ingo Molnar <mingo@...nel.org> Sent: Thursday, May 15, 2025 6:27 AM
> > >
> > > Since the x86 defconfig aims to be a distro kernel work-alike with
> > > fewer drivers and a shorter build time, refresh all the virtualization
> > > guest Kconfig features, enabling paravirt spinlocks, and
> > > enabling the guest support code for the following guests:
> > >
> > >  - Xen
> > >  - Xen_PVH
> > >  - Jailhouse
> > >  - ACRN
> > >  - Intel TDX
> > >  - Hyper-V
> >
> > I built and tested a Hyper-V guest with defconfig. The Hyper-V storage
> > and keyboard drivers are pulled in automatically, so my previous
> > comment about them being "missing" is moot.
> >
> > But the Linux console for each Hyper-V guest is a synthetic graphics
> > console,
> 
> So clearly I'm a caveman like creature, but surely those things have
> serial console, right? I mean, that's how I access all my test boxes,
> serial console and ssh. What more does one really need :-)
> 
> /me crawls back into his cave.

When Hyper-V is set up with Windows 10/11 on a laptop/desktop,
or with Windows Server on a lab/datacenter server, the UI to a new
VM is always a graphics console. The VM does have a virtual UART
for the serial console, but it requires manual steps to map to a named
pipe on the Windows host, and then running something like PuTTY
against the named pipe. I do exactly that when debugging a Linux
boot problem, but otherwise it's less hassle to use the graphics
console to boot up, and then ssh into the VM.

It would be nice if Hyper-V had an option to set up new VMs with
a serial console by default, but I doubt that will ever happen. That's
Hyper-V's legacy as a hypervisor for running Windows guests. :-(

In an Azure cloud VM, Azure automatically does the steps to set
up the serial console, which appears in the Azure Portal. So there's
no additional hassle.

Michael