| Message ID | 20240911204158.2034295-5-seanjc@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: selftests: Morph max_guest_mem to mmu_stress | expand |
On Wed, Sep 11, 2024 at 01:41:49PM GMT, Sean Christopherson wrote: > Assert that the the register being read/written by vcpu_{g,s}et_reg() is > no larger than a uint64_t, i.e. that a selftest isn't unintentionally > truncating the value being read/written. > > Ideally, the assert would be done at compile-time, but that would limit > the checks to hardcoded accesses and/or require fancier compile-time > assertion infrastructure to filter out dynamic usage. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > tools/testing/selftests/kvm/include/kvm_util.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h > index 429a7f003fe3..80230e49e35f 100644 > --- a/tools/testing/selftests/kvm/include/kvm_util.h > +++ b/tools/testing/selftests/kvm/include/kvm_util.h > @@ -683,6 +683,8 @@ static inline uint64_t vcpu_get_reg(struct kvm_vcpu *vcpu, uint64_t id) > uint64_t val; > struct kvm_one_reg reg = { .id = id, .addr = (uint64_t)&val }; > > + TEST_ASSERT(KVM_REG_SIZE(id) <= sizeof(val), "Reg %lx too big", id); > + > vcpu_ioctl(vcpu, KVM_GET_ONE_REG, ®); > return val; > } > @@ -690,6 +692,8 @@ static inline void vcpu_set_reg(struct kvm_vcpu *vcpu, uint64_t id, uint64_t val > { > struct kvm_one_reg reg = { .id = id, .addr = (uint64_t)&val }; > > + TEST_ASSERT(KVM_REG_SIZE(id) <= sizeof(val), "Reg %lx too big", id); > + > vcpu_ioctl(vcpu, KVM_SET_ONE_REG, ®); > } > > -- > 2.46.0.598.g6f2099f65c-goog > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Shouldn't patches 3 and 4 come before patch 2 in this series? Thanks, drew
On Thu, Sep 12, 2024, Andrew Jones wrote: > On Wed, Sep 11, 2024 at 01:41:49PM GMT, Sean Christopherson wrote: > > Assert that the the register being read/written by vcpu_{g,s}et_reg() is > > no larger than a uint64_t, i.e. that a selftest isn't unintentionally > > truncating the value being read/written. > > > > Ideally, the assert would be done at compile-time, but that would limit > > the checks to hardcoded accesses and/or require fancier compile-time > > assertion infrastructure to filter out dynamic usage. > > > > Signed-off-by: Sean Christopherson <seanjc@google.com> > > --- > > tools/testing/selftests/kvm/include/kvm_util.h | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h > > index 429a7f003fe3..80230e49e35f 100644 > > --- a/tools/testing/selftests/kvm/include/kvm_util.h > > +++ b/tools/testing/selftests/kvm/include/kvm_util.h > > @@ -683,6 +683,8 @@ static inline uint64_t vcpu_get_reg(struct kvm_vcpu *vcpu, uint64_t id) > > uint64_t val; > > struct kvm_one_reg reg = { .id = id, .addr = (uint64_t)&val }; > > > > + TEST_ASSERT(KVM_REG_SIZE(id) <= sizeof(val), "Reg %lx too big", id); > > + > > vcpu_ioctl(vcpu, KVM_GET_ONE_REG, ®); > > return val; > > } > > @@ -690,6 +692,8 @@ static inline void vcpu_set_reg(struct kvm_vcpu *vcpu, uint64_t id, uint64_t val > > { > > struct kvm_one_reg reg = { .id = id, .addr = (uint64_t)&val }; > > > > + TEST_ASSERT(KVM_REG_SIZE(id) <= sizeof(val), "Reg %lx too big", id); > > + > > vcpu_ioctl(vcpu, KVM_SET_ONE_REG, ®); > > } > > > > -- > > 2.46.0.598.g6f2099f65c-goog > > > > Reviewed-by: Andrew Jones <ajones@ventanamicro.com> > > Shouldn't patches 3 and 4 come before patch 2 in this series? Ideally, yes, but for this patch, it gets weird because the output param of vcpu_reg_get() isn't actually restricted to a 64-bit value prior to patch 2. E.g. if this patch were merged without that rework, then the assert would be confusing and arguably flat out wrong. As for the hack-a-fix, I deliberately ordered it after patch 2 so that it would be easier for others to (try to) reproduce the bug. I have no objection to swapping 2 and 3 in the next version.
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index 429a7f003fe3..80230e49e35f 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -683,6 +683,8 @@ static inline uint64_t vcpu_get_reg(struct kvm_vcpu *vcpu, uint64_t id) uint64_t val; struct kvm_one_reg reg = { .id = id, .addr = (uint64_t)&val }; + TEST_ASSERT(KVM_REG_SIZE(id) <= sizeof(val), "Reg %lx too big", id); + vcpu_ioctl(vcpu, KVM_GET_ONE_REG, ®); return val; } @@ -690,6 +692,8 @@ static inline void vcpu_set_reg(struct kvm_vcpu *vcpu, uint64_t id, uint64_t val { struct kvm_one_reg reg = { .id = id, .addr = (uint64_t)&val }; + TEST_ASSERT(KVM_REG_SIZE(id) <= sizeof(val), "Reg %lx too big", id); + vcpu_ioctl(vcpu, KVM_SET_ONE_REG, ®); }
Assert that the the register being read/written by vcpu_{g,s}et_reg() is no larger than a uint64_t, i.e. that a selftest isn't unintentionally truncating the value being read/written. Ideally, the assert would be done at compile-time, but that would limit the checks to hardcoded accesses and/or require fancier compile-time assertion infrastructure to filter out dynamic usage. Signed-off-by: Sean Christopherson <seanjc@google.com> --- tools/testing/selftests/kvm/include/kvm_util.h | 4 ++++ 1 file changed, 4 insertions(+)