3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Zhanghaoyu (A)" <haoyu.zhang@xxxxxxxxxx>
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@xxxxxxxxxx>
[Tweaks to commit message. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -558,8 +558,6 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu,
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,
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;
}
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