On Mon, Feb 20, 2017 at 12:30:12PM +0000, Mark Rutland wrote: > Currently we BUG() if we see an ESR_EL2.EC value we don't recognise. As > configurable disables/enables are added to the architecture (controlled > by RES1/RES0 bits respectively), with associated synchronous exceptions, > it may be possible for a guest to trigger exceptions with classes that > we don't recognise. > > While we can't service these exceptions in a manner useful to the guest, > we can avoid bringing down the host. Per ARM DDI 0487A.k_iss10775, page > D7-1937, EC values within the range 0x00 - 0x2c are reserved for future > use with synchronous exceptions, and EC values within the range 0x2d - > 0x3f may be used for either synchronous or asynchronous exceptions. > > The patch makes KVM handle any unknown EC by injecting an UNDEFINED > exception into the guest, with a corresponding (ratelimited) warning in > the host dmesg. We could later improve on this with with a new (opt-in) > exit to the host userspace. > > Signed-off-by: Mark Rutland <[email protected]> > Cc: Christoffer Dall <[email protected]> > Cc: Dave Martin <[email protected]> > Cc: Marc Zyngier <[email protected]> > Cc: Suzuki K Poulose <[email protected]> > --- > arch/arm64/kvm/handle_exit.c | 19 ++++++++++++------- > 1 file changed, 12 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 1bfe30d..fa1b18e 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -135,7 +135,19 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, > struct kvm_run *run) > return ret; > } > > +static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) > +{ > + u32 hsr = kvm_vcpu_get_hsr(vcpu); > + > + kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n", > + hsr, esr_get_class_string(hsr)); > + > + kvm_inject_undefined(vcpu); > + return 1; > +} > + > static exit_handle_fn arm_exit_handlers[] = { > + [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, > [ESR_ELx_EC_WFx] = kvm_handle_wfx, > [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, > [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64, > @@ -162,13 +174,6 @@ static exit_handle_fn kvm_get_exit_handler(struct > kvm_vcpu *vcpu) > u32 hsr = kvm_vcpu_get_hsr(vcpu); > u8 hsr_ec = ESR_ELx_EC(hsr); > > - if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) || > - !arm_exit_handlers[hsr_ec]) { > - kvm_err("Unknown exception class: hsr: %#08x -- %s\n", > - hsr, esr_get_class_string(hsr)); > - BUG(); > - } > - > return arm_exit_handlers[hsr_ec]; > } > > --
Reviewed-by: Christoffer Dall <[email protected]> _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
