diff options
Diffstat (limited to 'arch/x86/kvm/kvm_cache_regs.h')
| -rw-r--r-- | arch/x86/kvm/kvm_cache_regs.h | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 75eae9c4998a..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); } @@ -98,7 +115,7 @@ static inline unsigned long kvm_register_read_raw(struct kvm_vcpu *vcpu, int reg return 0; if (!kvm_register_is_available(vcpu, reg)) - static_call(kvm_x86_cache_reg)(vcpu, reg); + kvm_x86_call(cache_reg)(vcpu, reg); return vcpu->arch.regs[reg]; } @@ -138,7 +155,7 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index) might_sleep(); /* on svm */ if (!kvm_register_is_available(vcpu, VCPU_EXREG_PDPTR)) - static_call(kvm_x86_cache_reg)(vcpu, VCPU_EXREG_PDPTR); + kvm_x86_call(cache_reg)(vcpu, VCPU_EXREG_PDPTR); return vcpu->arch.walk_mmu->pdptrs[index]; } @@ -153,7 +170,7 @@ static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask) ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS; if ((tmask & vcpu->arch.cr0_guest_owned_bits) && !kvm_register_is_available(vcpu, VCPU_EXREG_CR0)) - static_call(kvm_x86_cache_reg)(vcpu, VCPU_EXREG_CR0); + kvm_x86_call(cache_reg)(vcpu, VCPU_EXREG_CR0); return vcpu->arch.cr0 & mask; } @@ -175,7 +192,7 @@ static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask) ulong tmask = mask & KVM_POSSIBLE_CR4_GUEST_BITS; if ((tmask & vcpu->arch.cr4_guest_owned_bits) && !kvm_register_is_available(vcpu, VCPU_EXREG_CR4)) - static_call(kvm_x86_cache_reg)(vcpu, VCPU_EXREG_CR4); + kvm_x86_call(cache_reg)(vcpu, VCPU_EXREG_CR4); return vcpu->arch.cr4 & mask; } @@ -190,7 +207,7 @@ static __always_inline bool kvm_is_cr4_bit_set(struct kvm_vcpu *vcpu, static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu) { if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3)) - static_call(kvm_x86_cache_reg)(vcpu, VCPU_EXREG_CR3); + kvm_x86_call(cache_reg)(vcpu, VCPU_EXREG_CR3); return vcpu->arch.cr3; } |