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| author | Sean Christopherson <seanjc@google.com> | 2024-08-02 20:55:09 +0200 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-11-01 17:22:34 +0100 |
| commit | 1ded7a57b8050ea92c0ab0253b11a917ae1427ff (patch) | |
| tree | c31cb447649e7026554018a61000440578a78584 /arch/x86 | |
| parent | KVM: x86: Reject userspace attempts to access ARCH_CAPABILITIES w/o support (diff) | |
| download | linux-1ded7a57b8050ea92c0ab0253b11a917ae1427ff.tar.xz linux-1ded7a57b8050ea92c0ab0253b11a917ae1427ff.zip | |
KVM: x86: Remove ordering check b/w MSR_PLATFORM_INFO and MISC_FEATURES_ENABLES
Drop KVM's odd restriction that disallows clearing CPUID_FAULT in
MSR_PLATFORM_INFO if CPL>0 CPUID faulting is enabled in
MSR_MISC_FEATURES_ENABLES. KVM generally doesn't require specific
ordering when userspace sets MSRs, and the completely arbitrary order of
MSRs in emulated_msrs_all means that a userspace that uses KVM's list
verbatim could run afoul of the check.
Dropping the restriction obviously means that userspace could stuff a
nonsensical vCPU model, but that's the case all over KVM. KVM typically
restricts userspace MSR writes only when it makes things easier for KVM
and/or userspace.
Link: https://lore.kernel.org/r/20240802185511.305849-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/x86.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7e59d3a0801a..366fd89d0894 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4116,9 +4116,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) vcpu->arch.osvw.status = data; break; case MSR_PLATFORM_INFO: - if (!msr_info->host_initiated || - (!(data & MSR_PLATFORM_INFO_CPUID_FAULT) && - cpuid_fault_enabled(vcpu))) + if (!msr_info->host_initiated) return 1; vcpu->arch.msr_platform_info = data; break; |