diff options
| author | Andy Honig <ahonig@google.com> | 2014-08-27 18:16:44 (GMT) |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-10-24 11:21:08 (GMT) |
| commit | 8b3c3104c3f4f706e99365c3e0d2aa61b95f969f (patch) | |
| tree | ccb686a3c75ce3b921a77038365752130b6ff589 /arch/x86/kvm | |
| parent | 854e8bb1aa06c578c2c9145fa6bfe3680ef63b23 (diff) | |
| download | linux-8b3c3104c3f4f706e99365c3e0d2aa61b95f969f.tar.xz | |
KVM: x86: Prevent host from panicking on shared MSR writes.
The previous patch blocked invalid writes directly when the MSR
is written. As a precaution, prevent future similar mistakes by
gracefulling handle GPs caused by writes to shared MSRs.
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Honig <ahonig@google.com>
[Remove parts obsoleted by Nadav's patch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 7 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 11 |
2 files changed, 13 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 148020a..7e2c098b 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2659,12 +2659,15 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) default: msr = find_msr_entry(vmx, msr_index); if (msr) { + u64 old_msr_data = msr->data; msr->data = data; if (msr - vmx->guest_msrs < vmx->save_nmsrs) { preempt_disable(); - kvm_set_shared_msr(msr->index, msr->data, - msr->mask); + ret = kvm_set_shared_msr(msr->index, msr->data, + msr->mask); preempt_enable(); + if (ret) + msr->data = old_msr_data; } break; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5a71955..0033df3 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); |