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| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-11-18 18:58:26 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-02-11 20:03:46 +0000 |
| commit | 6398f8c938d3eb074b5108a32d80c56f7a91b5c1 (patch) | |
| tree | ab9a696769591050c95daba0489285736bab94bc /arch/x86 | |
| parent | 653eb6d0723998fbea0d64b4231368df1d722f96 (diff) | |
| download | linux-stable-6398f8c938d3eb074b5108a32d80c56f7a91b5c1.tar.gz linux-stable-6398f8c938d3eb074b5108a32d80c56f7a91b5c1.tar.bz2 linux-stable-6398f8c938d3eb074b5108a32d80c56f7a91b5c1.zip | |
KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES
commit cbbaa2727aa3ae9e0a844803da7cef7fd3b94f2b upstream.
KVM does not implement MSR_IA32_TSX_CTRL, so it must not be presented
to the guests. It is also confusing to have !ARCH_CAP_TSX_CTRL_MSR &&
!RTM && ARCH_CAP_TAA_NO: lack of MSR_IA32_TSX_CTRL suggests TSX was not
hidden (it actually was), yet the value says that TSX is not vulnerable
to microarchitectural data sampling. Fix both.
Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d6711e5b9e78..bb4ed9190cbc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -945,10 +945,15 @@ u64 kvm_get_arch_capabilities(void) * If TSX is disabled on the system, guests are also mitigated against * TAA and clear CPU buffer mitigation is not required for guests. */ - if (boot_cpu_has_bug(X86_BUG_TAA) && boot_cpu_has(X86_FEATURE_RTM) && - (data & ARCH_CAP_TSX_CTRL_MSR)) + if (!boot_cpu_has(X86_FEATURE_RTM)) + data &= ~ARCH_CAP_TAA_NO; + else if (!boot_cpu_has_bug(X86_BUG_TAA)) + data |= ARCH_CAP_TAA_NO; + else if (data & ARCH_CAP_TSX_CTRL_MSR) data &= ~ARCH_CAP_MDS_NO; + /* KVM does not emulate MSR_IA32_TSX_CTRL. */ + data &= ~ARCH_CAP_TSX_CTRL_MSR; return data; } |