From: Cornelia Huck <cohuck@redhat.com>
To: Eric Farman <farman@linux.ibm.com>
Cc: Jason Herne <jjherne@linux.ibm.com>,
Thomas Huth <thuth@redhat.com>,
Janosch Frank <frankja@linux.ibm.com>,
Matthew Rosato <mjrosato@linux.ibm.com>,
qemu-devel@nongnu.org,
Christian Borntraeger <borntraeger@de.ibm.com>,
qemu-s390x@nongnu.org, Jared Rossi <jrossi@linux.ibm.com>
Subject: Re: [PATCH 1/2] pc-bios: s390x: Ensure Read IPL memory is clean
Date: Fri, 20 Nov 2020 10:26:26 +0100 [thread overview]
Message-ID: <20201120102626.45842232.cohuck@redhat.com> (raw)
In-Reply-To: <20201119165729.63351-2-farman@linux.ibm.com>
On Thu, 19 Nov 2020 17:57:28 +0100
Eric Farman <farman@linux.ibm.com> wrote:
> If, for example, we boot off a virtio device and chreipl to a vfio-ccw
> device, the space at lowcore will be non-zero. We build a Read IPL CCW
> at address zero, but it will have leftover PSW data that will conflict
> with the Format-0 CCW being generated:
>
> 0x0: 00080000 80010000
> ------ Ccw0.cda
> -- Ccw0.chainData
> -- Reserved bits
>
> The data address will be overwritten with the correct value (0x0), but
> the apparent data chain bit will cause subsequent memory to be used as
> the target of the data store, which may not be where we expect (0x0).
>
> Clear out this space when we boot from DASD, so that we know it exists
> exactly as we expect.
>
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
> Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
> pc-bios/s390-ccw/dasd-ipl.c | 3 +++
> 1 file changed, 3 insertions(+)
Acked-by: Cornelia Huck <cohuck@redhat.com>
next prev parent reply other threads:[~2020-11-20 9:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 16:57 [PATCH 0/2] pc-bios/s390 fixes for reboot-to-vfio-ccw Eric Farman
2020-11-19 16:57 ` [PATCH 1/2] pc-bios: s390x: Ensure Read IPL memory is clean Eric Farman
2020-11-19 20:06 ` Thomas Huth
2020-11-20 8:26 ` Janosch Frank
2020-11-20 14:39 ` Eric Farman
2020-11-20 9:26 ` Cornelia Huck [this message]
2020-11-19 16:57 ` [PATCH 2/2] pc-bios: s390x: Give precedence to reset PSW Eric Farman
2020-11-19 20:20 ` Thomas Huth
2020-11-19 21:11 ` Eric Farman
2020-11-20 6:02 ` Thomas Huth
2020-11-20 14:38 ` Eric Farman
2020-11-19 17:52 ` [PATCH 0/2] pc-bios/s390 fixes for reboot-to-vfio-ccw Cornelia Huck
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