1 files changed, 34 insertions, 4 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 34c8f94331f8..0033df32a745 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -229,20 +229,25 @@ static void kvm_shared_msr_cpu_online(void)
                 shared_msr_update(i, shared_msrs_global.msrs[i]);
 }
 
-void kvm_set_shared_msr(unsigned slot, u64 value, u64 mask)
+int kvm_set_shared_msr(unsigned slot, u64 value, u64 mask)
 {
         unsigned int cpu = smp_processor_id();
         struct kvm_shared_msrs *smsr = per_cpu_ptr(shared_msrs, cpu);
+        int err;
 
         if (((value ^ smsr->values[slot].curr) & mask) == 0)
-                return;
+                return 0;
         smsr->values[slot].curr = value;
-        wrmsrl(shared_msrs_global.msrs[slot], value);
+        err = wrmsrl_safe(shared_msrs_global.msrs[slot], value);
+        if (err)
+                return 1;
+
         if (!smsr->registered) {
                 smsr->urn.on_user_return = kvm_on_user_return;
                 user_return_notifier_register(&smsr->urn);
                 smsr->registered = true;
         }
+        return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_set_shared_msr);
 
@@ -987,7 +992,6 @@ void kvm_enable_efer_bits(u64 mask)
 }
 EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);
 
-
 /*
  * Writes msr value into into the appropriate "register".
  * Returns 0 on success, non-0 otherwise.
@@ -995,8 +999,34 @@ EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);
  */
 int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 {
+        switch (msr->index) {
+        case MSR_FS_BASE:
+        case MSR_GS_BASE:
+        case MSR_KERNEL_GS_BASE:
+        case MSR_CSTAR:
+        case MSR_LSTAR:
+                if (is_noncanonical_address(msr->data))
+                        return 1;
+                break;
+        case MSR_IA32_SYSENTER_EIP:
+        case MSR_IA32_SYSENTER_ESP:
+                /*
+                 * IA32_SYSENTER_ESP and IA32_SYSENTER_EIP cause #GP if
+                 * non-canonical address is written on Intel but not on
+                 * AMD (which ignores the top 32-bits, because it does
+                 * not implement 64-bit SYSENTER).
+                 *
+                 * 64-bit code should hence be able to write a non-canonical
+                 * value on AMD.  Making the address canonical ensures that
+                 * vmentry does not fail on Intel after writing a non-canonical
+                 * value, and that something deterministic happens if the guest
+                 * invokes 64-bit SYSENTER.
+                 */
+                msr->data = get_canonical(msr->data);
+        }
         return kvm_x86_ops->set_msr(vcpu, msr);
 }
+EXPORT_SYMBOL_GPL(kvm_set_msr);
 
 /*
  * Adapt set_msr() to msr_io()'s calling convention