lkml.org 
[lkml]   [2020]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v2 23/66] KVM: x86: Clear output regs for CPUID 0x14 if PT isn't exposed to guest
    Date
    Clear the output regs for the main CPUID 0x14 leaf (index=0) if Intel PT
    isn't exposed to the guest. Leaf 0x14 enumerates Intel PT capabilities
    and should return zeroes if PT is not supported. Incorrectly reporting
    PT capabilities is essentially a cosmetic error, i.e. doesn't negatively
    affect any known userspace/kernel, as the existence of PT itself is
    correctly enumerated via CPUID 0x7.

    Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
    ---
    arch/x86/kvm/cpuid.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
    index 1ff16300a468..c194e49622b9 100644
    --- a/arch/x86/kvm/cpuid.c
    +++ b/arch/x86/kvm/cpuid.c
    @@ -663,8 +663,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
    break;
    /* Intel PT */
    case 0x14:
    - if (!f_intel_pt)
    + if (!f_intel_pt) {
    + entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
    break;
    + }

    for (i = 1, max_idx = entry->eax; i <= max_idx; ++i) {
    if (!do_host_cpuid(array, function, i))
    --
    2.24.1
    \
     
     \ /
      Last update: 2020-03-03 01:10    [W:3.241 / U:0.812 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site