| From | Kamal Mostafa <> | Subject | [PATCH 058/105] KVM: x86: remove vcpu's CPL check in host-invoked XCR set | Date | Fri, 28 Jun 2013 11:51:20 -0700 |
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3.8.13.4 -stable review patch. If anyone has any objections, please let me know.
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From: "Zhanghaoyu (A)" <haoyu.zhang@huawei.com>
commit 764bcbc5a6d7a2f3e75c9f0e4caa984e2926e346 upstream.
__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.
Signed-off-by: Zhang Haoyu <haoyu.zhang@huawei.com> [Tweaks to commit message. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kvm/x86.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9a51121..ff74a2c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -558,8 +558,6 @@ 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)) @@ -573,7 +571,8 @@ 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; } -- 1.8.1.2
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