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KVM: x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally 

[ Upstream commit f4cfcd2d5a ]

This msr is only available when the host supports WAITPKG feature.

This breaks a nested guest, if the L1 hypervisor is set to ignore
unknown msrs, because the only other safety check that the
kernel does is that it attempts to read the msr and
rejects it if it gets an exception.

Cc: stable@vger.kernel.org
Fixes: 6e3ba4abce ("KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20200523161455.3940-3-mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit f4cfcd2d5a
use boot_cpu_has for checking the feature)
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Maxim Levitsky 2020-11-11 14:20:47 +01:00 committed by Greg Kroah-Hartman
parent d2cef3bae1
commit 4250160436
1 changed files with 4 additions and 0 deletions
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4
arch/x86/kvm/x86.c
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@ -5235,6 +5235,10 @@ static void kvm_init_msr_list(void)
if (!kvm_x86_ops->rdtscp_supported())
continue;
break;
case MSR_IA32_UMWAIT_CONTROL:
if (!boot_cpu_has(X86_FEATURE_WAITPKG))
continue;
break;
case MSR_IA32_RTIT_CTL:
case MSR_IA32_RTIT_STATUS:
if (!kvm_x86_ops->pt_supported())