diff options
Diffstat (limited to 'arch/x86/kvm/kvm_cache_regs.h')
| -rw-r--r-- | arch/x86/kvm/kvm_cache_regs.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index b1eb46e26b2e..36a8786db291 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -44,6 +44,18 @@ BUILD_KVM_GPR_ACCESSORS(r15, R15) #endif /* + * Using the register cache from interrupt context is generally not allowed, as + * caching a register and marking it available/dirty can't be done atomically, + * i.e. accesses from interrupt context may clobber state or read stale data if + * the vCPU task is in the process of updating the cache. The exception is if + * KVM is handling a PMI IRQ/NMI VM-Exit, as that bound code sequence doesn't + * touch the cache, it runs after the cache is reset (post VM-Exit), and PMIs + * need to access several registers that are cacheable. + */ +#define kvm_assert_register_caching_allowed(vcpu) \ + lockdep_assert_once(in_task() || kvm_arch_pmi_in_guest(vcpu)) + +/* * avail dirty * 0 0 register in VMCS/VMCB * 0 1 *INVALID* @@ -53,24 +65,28 @@ BUILD_KVM_GPR_ACCESSORS(r15, R15) static inline bool kvm_register_is_available(struct kvm_vcpu *vcpu, enum kvm_reg reg) { + kvm_assert_register_caching_allowed(vcpu); return test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); } static inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu, enum kvm_reg reg) { + kvm_assert_register_caching_allowed(vcpu); return test_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty); } static inline void kvm_register_mark_available(struct kvm_vcpu *vcpu, enum kvm_reg reg) { + kvm_assert_register_caching_allowed(vcpu); __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); } static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu, enum kvm_reg reg) { + kvm_assert_register_caching_allowed(vcpu); __set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); __set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty); } @@ -84,6 +100,7 @@ static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu, static __always_inline bool kvm_register_test_and_mark_available(struct kvm_vcpu *vcpu, enum kvm_reg reg) { + kvm_assert_register_caching_allowed(vcpu); return arch___test_and_set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); } |