diff options
| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-03-02 15:56:10 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-16 17:57:59 +0100 |
| commit | 1893c9415ae8cad20da863c41bdf308e56a2dd67 (patch) | |
| tree | 49da1aa11625955a64c76903523d4d16eed1cfb9 /arch/x86/kvm/cpuid.c | |
| parent | 3dc4a9cf05e53c358816f733e383ec42c86f3d4c (diff) | |
| download | lwn-1893c9415ae8cad20da863c41bdf308e56a2dd67.tar.gz lwn-1893c9415ae8cad20da863c41bdf308e56a2dd67.zip | |
KVM: x86: Check for CPUID 0xD.N support before validating array size
Now that sub-leaf 1 is handled separately, verify the next sub-leaf is
needed before rejecting KVM_GET_SUPPORTED_CPUID due to an insufficiently
sized userspace array.
Note, although this is technically a bug, it's not visible to userspace
as KVM_GET_SUPPORTED_CPUID is guaranteed to fail on KVM_CPUID_SIGNATURE,
which is hardcoded to be added after leaf 0xD. The real motivation for
the change is to tightly couple the nent/maxnent and do_host_cpuid()
sequences in preparation for future cleanup.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index fc8540596386..fd9b29aa7abc 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -670,13 +670,14 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function, entry[1].edx = 0; for (idx = 2, i = 2; idx < 64; ++idx) { - u64 mask = ((u64)1 << idx); + if (!(supported & BIT_ULL(idx))) + continue; if (*nent >= maxnent) goto out; do_host_cpuid(&entry[i], function, idx); - if (entry[i].eax == 0 || !(supported & mask)) + if (entry[i].eax == 0) continue; if (WARN_ON_ONCE(entry[i].ecx & 1)) continue; |