From: Christoph Hellwig <hch@infradead.org>
To: Janosch Frank <frankja@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Eric Farman <farman@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Hendrik Brueckner <brueckner@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
David Hildenbrand <david@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
kvm@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v1 0/4] KVM: s390: Permit ESA mode guests in VSIE
Date: Sun, 5 Apr 2026 22:37:29 -0700 [thread overview]
Message-ID: <adNGmUzxx5OCK69e@infradead.org> (raw)
In-Reply-To: <bbd43c25-b624-4e23-8870-6116532316a8@linux.ibm.com>
On Wed, Apr 01, 2026 at 12:00:59PM +0200, Janosch Frank wrote:
> KVM is the latest hypervisor in a long list on s390. As such we implemented
> the newest architecture as our starting point and only architecture
> (zArch/64bit).
>
> There are others which don't start their guests from zArch mode but start
> them in ESA and slowly move them through modes until they reach zArch. Those
> other hypervisors often implement emulation for features and devices that
> KVM doesn't support so there's some demand for using them.
>
> Why do we nest those hypervisors under KVM? We have products that work with
> the KVM API so it's easier to nest than to re-write the product to use other
> hypervisors in the first place.
Makes sense. Maybe mention this in the cover letter, and also that
you're not looking into full device model support for older systems?
prev parent reply other threads:[~2026-04-06 5:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-01 2:09 [PATCH v1 0/4] KVM: s390: Permit ESA mode guests in VSIE Eric Farman
2026-04-01 2:09 ` [PATCH v1 1/4] KVM: s390: vsie: Allow non-zarch guests Eric Farman
2026-04-01 11:25 ` Janosch Frank
2026-04-01 13:31 ` Eric Farman
2026-04-01 2:09 ` [PATCH v1 2/4] KVM: s390: vsie: Disable some bits when in ESA mode Eric Farman
2026-04-01 12:58 ` Christian Borntraeger
2026-04-01 13:46 ` Eric Farman
2026-04-01 14:50 ` Janosch Frank
2026-04-01 2:09 ` [PATCH v1 3/4] KVM: s390: vsie: Accommodate ESA prefix pages Eric Farman
2026-04-01 11:45 ` Janosch Frank
2026-04-01 13:44 ` Eric Farman
2026-04-01 2:09 ` [PATCH v1 4/4] KVM: s390: Add KVM capability for ESA mode guests Eric Farman
2026-04-01 11:52 ` Janosch Frank
2026-04-01 6:40 ` [PATCH v1 0/4] KVM: s390: Permit ESA mode guests in VSIE Christoph Hellwig
2026-04-01 10:00 ` Janosch Frank
2026-04-06 5:37 ` Christoph Hellwig [this message]
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