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| author | Andy Honig <ahonig@google.com> | 2014-08-27 11:16:44 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-10-24 13:21:08 +0200 |
| commit | 8b3c3104c3f4f706e99365c3e0d2aa61b95f969f (patch) | |
| tree | ccb686a3c75ce3b921a77038365752130b6ff589 /arch/x86/kvm/x86.c | |
| parent | 854e8bb1aa06c578c2c9145fa6bfe3680ef63b23 (diff) | |
| download | lwn-8b3c3104c3f4f706e99365c3e0d2aa61b95f969f.tar.gz lwn-8b3c3104c3f4f706e99365c3e0d2aa61b95f969f.zip | |
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/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5a7195573a32..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); |