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author | Paolo Bonzini <pbonzini@redhat.com> | 2022-04-29 14:43:04 -0400 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-04-29 15:24:58 -0400 |
commit | f751d8eac17692905cdd6935f72d523d8adf3b65 (patch) | |
tree | b75ec91ec9ede7ff337470e7e3a021837dccee7a /arch/arm64 | |
parent | 643d95aac59a060c2730975988aedc387f0f9f44 (diff) | |
download | linux-f751d8eac17692905cdd6935f72d523d8adf3b65.tar.gz linux-f751d8eac17692905cdd6935f72d523d8adf3b65.tar.bz2 linux-f751d8eac17692905cdd6935f72d523d8adf3b65.zip |
KVM: x86: work around QEMU issue with synthetic CPUID leaves
Synthesizing AMD leaves up to 0x80000021 caused problems with QEMU,
which assumes the *host* CPUID[0x80000000].EAX is higher or equal
to what KVM_GET_SUPPORTED_CPUID reports.
This causes QEMU to issue bogus host CPUIDs when preparing the input
to KVM_SET_CPUID2. It can even get into an infinite loop, which is
only terminated by an abort():
cpuid_data is full, no space for cpuid(eax:0x8000001d,ecx:0x3e)
To work around this, only synthesize those leaves if 0x8000001d exists
on the host. The synthetic 0x80000021 leaf is mostly useful on Zen2,
which satisfies the condition.
Fixes: f144c49e8c39 ("KVM: x86: synthesize CPUID leaf 0x80000021h if useful")
Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/arm64')
0 files changed, 0 insertions, 0 deletions