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authorPaolo Bonzini <pbonzini@redhat.com>2019-11-18 18:58:26 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-12-17 20:38:52 +0100
commitcd606fb8f575ec2eaca138d9b3ba3b5131d9a875 (patch)
tree366adcdd8e1511fa1d798a07ed726c6f05596404 /arch
parenta5591672b05c953ec07f6aec042d25d58956e553 (diff)
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. Cc: stable@vger.kernel.org Tested-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/x86.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 08ec754561b8..8a51442247c5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1113,10 +1113,15 @@ 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;
}