From: David Hildenbrand <david@redhat.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Thomas Huth <thuth@redhat.com>,
Janosch Frank <frankja@linux.ibm.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
qemu-devel@nongnu.org, Halil Pasic <pasic@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
qemu-s390x@nongnu.org, Claudio Imbrenda <imbrenda@linux.ibm.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH RFC 2/5] s390x: implement diag260
Date: Fri, 10 Jul 2020 17:24:07 +0200 [thread overview]
Message-ID: <10bdd986-c474-278d-ed6a-193d9a45fe33@redhat.com> (raw)
In-Reply-To: <20200710151816.GC14845@osiris>
On 10.07.20 17:18, Heiko Carstens wrote:
> On Fri, Jul 10, 2020 at 02:12:33PM +0200, David Hildenbrand wrote:
>>> Note: Reading about diag260 subcode 0xc, we could modify Linux to query
>>> the maximum possible pfn via diag260 0xc. Then, we maybe could avoid
>>> indicating maxram size via SCLP, and keep diag260-unaware OSs keep
>>> working as before. Thoughts?
>>
>> Implemented it, seems to work fine.
>
> The returned value would not include standby/reserved memory within
> z/VM. So this seems not to work.
Which value exactly are you referencing? diag 0xc returns two values.
One of them seems to do exactly what we need.
See
https://github.com/davidhildenbrand/linux/commit/a235f9fb20df7c04ae89bc0d134332d1a01842c7
for my current Linux approach.
> Also: why do you want to change this
Which change exactly do you mean?
If we limit the value returned via SCLP to initial memory, we cannot
break any guest (e.g., Linux pre 4.2, kvm-unit-tests). diag260 is then
purely optional.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-07-10 15:25 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 18:51 [PATCH RFC 0/5] s390x: initial support for virtio-mem David Hildenbrand
2020-07-08 18:51 ` [PATCH RFC 1/5] s390x: move setting of maximum ram size to machine init David Hildenbrand
2020-07-08 18:51 ` [PATCH RFC 2/5] s390x: implement diag260 David Hildenbrand
2020-07-09 10:37 ` Cornelia Huck
2020-07-09 17:54 ` David Hildenbrand
2020-07-10 8:32 ` David Hildenbrand
2020-07-10 8:41 ` David Hildenbrand
2020-07-10 9:19 ` Cornelia Huck
2020-07-13 11:54 ` Christian Borntraeger
2020-07-13 12:11 ` Cornelia Huck
2020-07-13 12:13 ` Christian Borntraeger
2020-07-09 10:52 ` Christian Borntraeger
2020-07-09 18:15 ` David Hildenbrand
2020-07-10 9:17 ` David Hildenbrand
2020-07-10 12:12 ` David Hildenbrand
2020-07-10 15:18 ` Heiko Carstens
2020-07-10 15:24 ` David Hildenbrand [this message]
2020-07-10 15:43 ` Heiko Carstens
2020-07-10 15:45 ` David Hildenbrand
2020-07-13 9:12 ` Heiko Carstens
2020-07-13 10:27 ` David Hildenbrand
2020-07-13 11:08 ` Christian Borntraeger
2020-07-15 9:42 ` David Hildenbrand
2020-07-15 10:43 ` Heiko Carstens
2020-07-15 11:21 ` David Hildenbrand
2020-07-15 11:34 ` Heiko Carstens
2020-07-15 11:42 ` David Hildenbrand
2020-07-15 16:14 ` Heiko Carstens
2020-07-15 17:38 ` David Hildenbrand
2020-07-15 17:51 ` David Hildenbrand
2020-07-20 14:43 ` Heiko Carstens
2020-07-20 15:43 ` David Hildenbrand
2020-07-08 18:51 ` [PATCH RFC 3/5] s390x: prepare device memory address space David Hildenbrand
2020-07-09 10:59 ` Cornelia Huck
2020-07-10 7:46 ` David Hildenbrand
2020-07-08 18:51 ` [PATCH RFC 4/5] s390x: implement virtio-mem-ccw David Hildenbrand
2020-07-09 9:24 ` Cornelia Huck
2020-07-09 9:26 ` David Hildenbrand
2020-07-08 18:51 ` [PATCH RFC 5/5] s390x: initial support for virtio-mem David Hildenbrand
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