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Blame SOURCES/kvm-exec-check-that-alignment-is-a-power-of-two.patch

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From f5eecfb16d182d3c37df06bf20e6843f126b33fe Mon Sep 17 00:00:00 2001
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From: David Hildenbrand <david@redhat.com>
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Date: Fri, 21 Sep 2018 10:18:00 +0100
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Subject: [PATCH 3/4] exec: check that alignment is a power of two
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RH-Author: David Hildenbrand <david@redhat.com>
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Message-id: <20180921101800.27360-1-david@redhat.com>
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Patchwork-id: 82229
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O-Subject: [RHEL-8.0 qemu-kvm PATCH] exec: check that alignment is a power of two
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Bugzilla: 1630746
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RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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RH-Acked-by: Pankaj Gupta <pagupta@redhat.com>
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RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1630746
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Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=18439951
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Branch: rhel8/master-2.12.0
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Upstream: 61362b71c105ccb151ca16897a7d56534423f390
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Right now we can crash QEMU using e.g.
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qemu-system-x86_64 -m 256M,maxmem=20G,slots=2 \
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 -object memory-backend-file,id=mem0,size=12288,mem-path=/dev/zero,align=12288 \
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 -device pc-dimm,id=dimm1,memdev=mem0
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qemu-system-x86_64: util/mmap-alloc.c:115:
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 qemu_ram_mmap: Assertion `is_power_of_2(align)' failed
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Fix this by adding a proper check.
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Signed-off-by: David Hildenbrand <david@redhat.com>
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Message-Id: <20180607154705.6316-3-david@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Reviewed-by: Igor Mammedov <imammedo@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 61362b71c105ccb151ca16897a7d56534423f390)
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Signed-off-by: David Hildenbrand <david@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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 exec.c | 4 ++++
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 1 file changed, 4 insertions(+)
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diff --git a/exec.c b/exec.c
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index 02b1efe..22cc7ef 100644
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--- a/exec.c
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+++ b/exec.c
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@@ -1646,6 +1646,10 @@ static void *file_ram_alloc(RAMBlock *block,
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                    " must be multiples of page size 0x%zx",
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                    block->mr->align, block->page_size);
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         return NULL;
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+    } else if (block->mr->align && !is_power_of_2(block->mr->align)) {
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+        error_setg(errp, "alignment 0x%" PRIx64
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+                   " must be a power of two", block->mr->align);
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+        return NULL;
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     }
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     block->mr->align = MAX(block->page_size, block->mr->align);
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 #if defined(__s390x__)
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-- 
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1.8.3.1
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