38 lines
1.5 KiB
Diff
38 lines
1.5 KiB
Diff
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commit 9267342206ce17f6933d57a3128cdc504d5945c9
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Author: Daniel P. Berrangé <berrange@redhat.com>
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Date: Mon May 21 23:05:08 2018 +0100
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cpu: define the 'virt-ssbd' CPUID feature bit (CVE-2018-3639)
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Some AMD processors only support a non-architectural means of
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enabling Speculative Store Bypass Disable. To allow simplified
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handling in virtual environments, hypervisors will expose an
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architectural definition through CPUID bit 0x80000008_EBX[25].
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This needs to be exposed to guest OS running on AMD x86 hosts to
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allow them to protect against CVE-2018-3639.
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Note that since this CPUID bit won't be present in the host CPUID
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results on physical hosts, it will not be enabled automatically
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in guests configured with "host-model" CPU unless using QEMU
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version >= 2.9.0. Thus for older versions of QEMU, this feature
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must be manually enabled using policy=force. Guests using the
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"host-passthrough" CPU mode do not need special handling.
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Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
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Index: libvirt-4.3.0/src/cpu/cpu_map.xml
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===================================================================
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--- libvirt-4.3.0.orig/src/cpu/cpu_map.xml
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+++ libvirt-4.3.0/src/cpu/cpu_map.xml
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@@ -433,6 +433,9 @@
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<feature name='ibpb'>
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<cpuid eax_in='0x80000008' ebx='0x00001000'/>
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</feature>
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+ <feature name='virt-ssbd'>
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+ <cpuid eax_in='0x80000008' ebx='0x02000000'/>
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+ </feature>
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<!-- models -->
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<model name='486'>
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