__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(QEMU), call stack shown as below,
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>
---
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 094b5d9..16ff44e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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;
}
1.7.3.1.msysgit.0
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