From: Cornelia Huck <cohuck@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: qemu-devel@nongnu.org, thuth@redhat.com,
Christian Borntraeger <borntraeger@de.ibm.com>,
Alexander Graf <agraf@suse.de>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [Qemu-devel] [PATCH v1 0/6] s390x/tcg: fix some accesses using low address
Date: Wed, 27 Sep 2017 13:49:10 +0200 [thread overview]
Message-ID: <20170927134910.0ffccb7e.cohuck@redhat.com> (raw)
In-Reply-To: <20170926183318.12995-1-david@redhat.com>
On Tue, 26 Sep 2017 20:33:12 +0200
David Hildenbrand <david@redhat.com> wrote:
> Conny reported that a guest Linux currently spits out:
> "The s390-virtio transport is deprecated. Please switch to a modern host
> providing virtio-ccw."
>
> This is strange, because we have no legacy virtio transport in QEMU :)
>
> Main problem is, that a page is tested for acccess, and the test does not
> fail. All memory access variants like stb_phys() will never fail. On
> invalid memory, they simply do nothing.
>
> Linux uses lura for this check. Let's introduce a _real MMU that handles
> prefixing and can later be used for things like low address protection.
>
> The other BUG is that a check for invalid memory is wrong. Therefore,
> Patch 1 alone makes the guest crash when trying to initialize the
> virtio transport. Crazy stuff.
Indeed, thanks for hunting this down! No strange messages for me any
more :)
Fixed up the empty line in lura and applied to s390-next.
prev parent reply other threads:[~2017-09-27 11:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-26 18:33 [Qemu-devel] [PATCH v1 0/6] s390x/tcg: fix some accesses using low address David Hildenbrand
2017-09-26 18:33 ` [Qemu-devel] [PATCH v1 1/6] s390x/tcg: fix checking for invalid memory check David Hildenbrand
2017-09-26 18:33 ` [Qemu-devel] [PATCH v1 2/6] s390x/tcg: add MMU for real addresses David Hildenbrand
2017-09-27 12:20 ` David Hildenbrand
2017-09-26 18:33 ` [Qemu-devel] [PATCH v1 3/6] s390x/tcg: make lura(g) use the new _real mmu David Hildenbrand
2017-09-26 18:33 ` [Qemu-devel] [PATCH v1 4/6] s390x/tcg: make stora(g) " David Hildenbrand
2017-09-26 18:33 ` [Qemu-devel] [PATCH v1 5/6] s390x/tcg: make testblock " David Hildenbrand
2017-09-26 18:33 ` [Qemu-devel] [PATCH v1 6/6] s390x/tcg: make idte/ipte " David Hildenbrand
2017-09-26 23:10 ` [Qemu-devel] [PATCH v1 0/6] s390x/tcg: fix some accesses using low address Richard Henderson
2017-09-27 7:38 ` Thomas Huth
2017-09-27 11:49 ` Cornelia Huck [this message]
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