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-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--arch/x86/kvm/vmx/vmx.c5
-rw-r--r--arch/x86/kvm/x86.c16
3 files changed, 18 insertions, 4 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 848956bb3cf1..e8dcbc632cf8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1777,6 +1777,7 @@ int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low,
unsigned long icr, int op_64_bit);
void kvm_define_user_return_msr(unsigned index, u32 msr);
+int kvm_probe_user_return_msr(u32 msr);
int kvm_set_user_return_msr(unsigned index, u64 val, u64 mask);
u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4a625c748275..11ff9c3d95d5 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6914,12 +6914,9 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
for (i = 0; i < ARRAY_SIZE(vmx_uret_msrs_list); ++i) {
u32 index = vmx_uret_msrs_list[i];
- u32 data_low, data_high;
int j = vmx->nr_uret_msrs;
- if (rdmsr_safe(index, &data_low, &data_high) < 0)
- continue;
- if (wrmsr_safe(index, data_low, data_high) < 0)
+ if (kvm_probe_user_return_msr(index))
continue;
vmx->guest_uret_msrs[j].slot = i;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 102f116d9bb4..bd90c73c37b4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -339,6 +339,22 @@ static void kvm_on_user_return(struct user_return_notifier *urn)
}
}
+int kvm_probe_user_return_msr(u32 msr)
+{
+ u64 val;
+ int ret;
+
+ preempt_disable();
+ ret = rdmsrl_safe(msr, &val);
+ if (ret)
+ goto out;
+ ret = wrmsrl_safe(msr, val);
+out:
+ preempt_enable();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_probe_user_return_msr);
+
void kvm_define_user_return_msr(unsigned slot, u32 msr)
{
BUG_ON(slot >= KVM_MAX_NR_USER_RETURN_MSRS);