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KVM: x86: remove vcpu's CPL check in host-invoked XCR set 

__kvm_set_xcr function does the CPL check when set xcr. __kvm_set_xcr is
called in two flows, one is invoked by guest, call stack shown as below,

  handle_xsetbv(or xsetbv_interception)
    kvm_set_xcr
      __kvm_set_xcr

the other one is invoked by host, for example during system reset:

  kvm_arch_vcpu_ioctl
    kvm_vcpu_ioctl_x86_set_xcrs
      __kvm_set_xcr

The former does need the CPL check, but the latter does not.

Cc: stable@vger.kernel.org
Signed-off-by: Zhang Haoyu <haoyu.zhang@huawei.com>
[Tweaks to commit message. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Zhanghaoyu (A) 2013-06-14 07:36:13 +00:00 committed by Paolo Bonzini
parent 77293e215e
commit 764bcbc5a6
1 changed files with 2 additions and 3 deletions
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5
arch/x86/kvm/x86.c
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@ -582,8 +582,6 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
if (index != XCR_XFEATURE_ENABLED_MASK)
return 1;
xcr0 = xcr;
if (kvm_x86_ops->get_cpl(vcpu) != 0)
return 1;
if (!(xcr0 & XSTATE_FP))
return 1;
if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
@ -597,7 +595,8 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
if (__kvm_set_xcr(vcpu, index, xcr)) {
if (kvm_x86_ops->get_cpl(vcpu) != 0 ||
__kvm_set_xcr(vcpu, index, xcr)) {
kvm_inject_gp(vcpu, 0);
return 1;
}