On Tue, Jul 30, 2013 at 05:11:35PM +0200, Paolo Bonzini wrote: > This lets debugging work better during emulation of invalid > guest state. > > The check is done before emulating the instruction, and (in the case > of guest debugging) reuses EMULATE_DO_MMIO to exit with KVM_EXIT_DEBUG. > Not EMULATE_DO_MMIO any more. Otherwise looks good.
> Signed-off-by: Paolo Bonzini <[email protected]> > --- > arch/x86/kvm/x86.c | 66 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 66 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index c2a0674..1368cf5 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4956,6 +4956,62 @@ static bool retry_instruction(struct x86_emulate_ctxt > *ctxt, > static int complete_emulated_mmio(struct kvm_vcpu *vcpu); > static int complete_emulated_pio(struct kvm_vcpu *vcpu); > > +static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7, > + unsigned long *db) > +{ > + u32 dr6 = 0; > + int i; > + u32 enable, rwlen; > + > + enable = dr7; > + rwlen = dr7 >> 16; > + for (i = 0; i < 4; i++, enable >>= 2, rwlen >>= 4) > + if ((enable & 3) && (rwlen & 15) == type && db[i] == addr) > + dr6 |= (1 << i); > + return dr6; > +} > + > +static bool kvm_vcpu_check_breakpoint(struct kvm_vcpu *vcpu, int *r) > +{ > + struct kvm_run *kvm_run = vcpu->run; > + unsigned long eip = vcpu->arch.emulate_ctxt.eip; > + u32 dr6 = 0; > + > + if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) && > + (vcpu->arch.guest_debug_dr7 & DR7_BP_EN_MASK)) { > + dr6 = kvm_vcpu_check_hw_bp(eip, 0, > + vcpu->arch.guest_debug_dr7, > + vcpu->arch.eff_db); > + > + if (dr6 != 0) { > + kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1; > + kvm_run->debug.arch.pc = kvm_rip_read(vcpu) + > + get_segment_base(vcpu, VCPU_SREG_CS); > + > + kvm_run->debug.arch.exception = DB_VECTOR; > + kvm_run->exit_reason = KVM_EXIT_DEBUG; > + *r = EMULATE_USER_EXIT; > + return true; > + } > + } > + > + if (unlikely(vcpu->arch.dr7 & DR7_BP_EN_MASK)) { > + dr6 = kvm_vcpu_check_hw_bp(eip, 0, > + vcpu->arch.dr7, > + vcpu->arch.db); > + > + if (dr6 != 0) { > + vcpu->arch.dr6 &= ~15; > + vcpu->arch.dr6 |= dr6; > + kvm_queue_exception(vcpu, DB_VECTOR); > + *r = EMULATE_DONE; > + return true; > + } > + } > + > + return false; > +} > + > int x86_emulate_instruction(struct kvm_vcpu *vcpu, > unsigned long cr2, > int emulation_type, > @@ -4976,6 +5032,16 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, > > if (!(emulation_type & EMULTYPE_NO_DECODE)) { > init_emulate_ctxt(vcpu); > + > + /* > + * We will reenter on the same instruction since > + * we do not set complete_userspace_io. This does not > + * handle watchpoints yet, those would be handled in > + * the emulate_ops. > + */ > + if (kvm_vcpu_check_breakpoint(vcpu, &r)) > + return r; > + > ctxt->interruptibility = 0; > ctxt->have_exception = false; > ctxt->perm_ok = false; > -- > 1.8.1.4 > -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
