[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 3/3] x86/svm: Improve diagnostics when svm_get_insn_len() fails
> -----Original Message----- > From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx] > Sent: 31 December 2018 11:38 > To: Xen-devel <xen-devel@xxxxxxxxxxxxx> > Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Jan Beulich > <JBeulich@xxxxxxxx>; Wei Liu <wei.liu2@xxxxxxxxxx>; Roger Pau Monne > <roger.pau@xxxxxxxxxx>; Paul Durrant <Paul.Durrant@xxxxxxxxxx>; Boris > Ostrovsky <boris.ostrovsky@xxxxxxxxxx>; Suravee Suthikulpanit > <suravee.suthikulpanit@xxxxxxx>; Brian Woods <brian.woods@xxxxxxx> > Subject: [PATCH v3 3/3] x86/svm: Improve diagnostics when > svm_get_insn_len() fails > > Sadly, a lone: > > (XEN) emulate.c:156:d2v0 svm_get_insn_len: Mismatch between expected and > actual instruction: eip = fffff804564139c0 > > on the console is of no use trying to identify what went wrong. Dump as > much > state as we can to help identify what went wrong. > > (XEN) Insn mismatch: Expected opcode 0xf0031, modrm 0, got nrip_len 3, > emul_len 3 > (XEN) SVM Insn len emulation failed (1): d1v0 64bit @ 0008:0010475f -> > 0f 01 f9 0f 31 5b 31 ff 31 c0 e9 c2 db ff ff 00 > > Drop the debug-only early exit if the sources of length disagree, because > the > only effect it has it to avoid the more detailed analysis of what went > wrong. > > Reported-by: Paul Durrant <paul.durrant@xxxxxxxxxx> > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > Acked-by: Brian Woods <brian.woods@xxxxxxx> Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx> > --- > CC: Jan Beulich <JBeulich@xxxxxxxx> > CC: Wei Liu <wei.liu2@xxxxxxxxxx> > CC: Roger Pau Monné <roger.pau@xxxxxxxxxx> > CC: Paul Durrant <paul.durrant@xxxxxxxxxx> > CC: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx> > CC: Brian Woods <brian.woods@xxxxxxx> > > v2: > * Drop anonymous union > * Rebase > v3: > * Rework yet again, over the removal of enum instruction_index > --- > xen/arch/x86/hvm/svm/emulate.c | 19 ++++++------------- > 1 file changed, 6 insertions(+), 13 deletions(-) > > diff --git a/xen/arch/x86/hvm/svm/emulate.c > b/xen/arch/x86/hvm/svm/emulate.c > index 827cfc8..4000087 100644 > --- a/xen/arch/x86/hvm/svm/emulate.c > +++ b/xen/arch/x86/hvm/svm/emulate.c > @@ -65,7 +65,6 @@ static unsigned long svm_nextrip_insn_length(struct vcpu > *v) > */ > unsigned int svm_get_insn_len(struct vcpu *v, unsigned int instr_enc) > { > - struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb; > struct hvm_emulate_ctxt ctxt; > struct x86_emulate_state *state; > unsigned long nrip_len, emul_len; > @@ -93,15 +92,6 @@ unsigned int svm_get_insn_len(struct vcpu *v, unsigned > int instr_enc) > modrm_mod = x86_insn_modrm(state, &modrm_rm, &modrm_reg); > x86_emulate_free_state(state); > > -#ifndef NDEBUG > - if ( nrip_len && nrip_len != emul_len ) > - { > - gprintk(XENLOG_WARNING, "insn-len[%02x]=%lu (exp %lu)\n", > - ctxt.ctxt.opcode, nrip_len, emul_len); > - return nrip_len; > - } > -#endif > - > /* Extract components from instr_enc. */ > instr_modrm = instr_enc & 0xff; > instr_opcode = instr_enc >> 8; > @@ -117,9 +107,12 @@ unsigned int svm_get_insn_len(struct vcpu *v, > unsigned int instr_enc) > return emul_len; > } > > - gdprintk(XENLOG_WARNING, > - "%s: Mismatch between expected and actual instruction: " > - "eip = %lx\n", __func__, (unsigned long)vmcb->rip); > + printk(XENLOG_G_WARNING > + "Insn mismatch: Expected opcode %#x, modrm %#x, got nrip_len > %lu, emul_len %lu\n", > + instr_opcode, instr_modrm, nrip_len, emul_len); > + hvm_dump_emulation_state(XENLOG_G_WARNING, "SVM Insn len", > + &ctxt, X86EMUL_UNHANDLEABLE); > + > hvm_inject_hw_exception(TRAP_gp_fault, 0); > return 0; > } > -- > 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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