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Commit 764bcbc5 authored by Zhanghaoyu (A)'s avatar Zhanghaoyu (A) Committed by Paolo Bonzini
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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: default avatarZhang Haoyu <haoyu.zhang@huawei.com>
[Tweaks to commit message. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 77293e21

arch/x86/kvm/x86.c

+2 −3
Original line number Original line Diff line number Diff line
@@ -582,8 +582,6 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr) 
	if (index != XCR_XFEATURE_ENABLED_MASK)

	if (index != XCR_XFEATURE_ENABLED_MASK)

		return 1;

		return 1;

	xcr0 = xcr;

	xcr0 = xcr;

	if (kvm_x86_ops->get_cpl(vcpu) != 0)

		return 1;

	if (!(xcr0 & XSTATE_FP))

	if (!(xcr0 & XSTATE_FP))

		return 1;

		return 1;

	if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))

	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)

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);

		kvm_inject_gp(vcpu, 0);

		return 1;

		return 1;

	}

	}