74 lines
2.8 KiB
Diff
74 lines
2.8 KiB
Diff
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From 10cd7878be0501be1e27b7b00c14958efcdb3d9b Mon Sep 17 00:00:00 2001
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From: Cornelia Huck <cohuck@redhat.com>
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Date: Wed, 17 Apr 2019 13:57:22 +0100
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Subject: [PATCH 05/24] s390x/cpumodel: fix segmentation fault when baselining
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models
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Cornelia Huck <cohuck@redhat.com>
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Message-id: <20190417135741.25297-6-cohuck@redhat.com>
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Patchwork-id: 85784
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O-Subject: [RHEL-8.1.0 qemu-kvm PATCH v2 05/24] s390x/cpumodel: fix segmentation fault when baselining models
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Bugzilla: 1699070
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RH-Acked-by: David Hildenbrand <david@redhat.com>
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RH-Acked-by: Thomas Huth <thuth@redhat.com>
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Jens Freimann <jfreimann@redhat.com>
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From: David Hildenbrand <david@redhat.com>
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Usually, when baselining two CPU models, whereby one of them has base
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CPU features disabled (e.g. z14-base,msa=off), we fallback to an older
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model that did not have these features in the base model. We always try to
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create a "sane" CPU model (as far as possible), and one part of it is that
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removing base features is no good and to be avoided.
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Now, if we disable base features that were part of a z900, we're out of
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luck. We won't find a CPU model and QEMU will segfault. This is a
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scenario that should never happen in real life, but it can be used to
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crash QEMU.
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So let's properly report an error if we baseline e.g.:
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{ "execute": "query-cpu-model-baseline",
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"arguments" : { "modela": { "name": "z14-base", "props": {"esan3" : false}},
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"modelb": { "name": "z14"}} }
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Instead of segfaulting.
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Signed-off-by: David Hildenbrand <david@redhat.com>
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Message-Id: <20180718092330.19465-1-david@redhat.com>
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Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
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Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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(cherry picked from commit 677ff32db12bcd1bca3a3df733d2478896d6df96)
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Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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target/s390x/cpu_models.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
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index 5e9b716..d2c16b8 100644
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--- a/target/s390x/cpu_models.c
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+++ b/target/s390x/cpu_models.c
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@@ -720,6 +720,14 @@ CpuModelBaselineInfo *arch_query_cpu_model_baseline(CpuModelInfo *infoa,
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model.def = s390_find_cpu_def(cpu_type, max_gen, max_gen_ga,
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model.features);
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+
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+ /* models without early base features (esan3) are bad */
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+ if (!model.def) {
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+ error_setg(errp, "No compatible CPU model could be created as"
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+ " important base features are disabled");
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+ return NULL;
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+ }
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+
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/* strip off features not part of the max model */
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bitmap_and(model.features, model.features, model.def->full_feat,
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S390_FEAT_MAX);
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--
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1.8.3.1
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