From 96720ccf3ad1b6cbe7c11069a3bc730bd0fe7fa3 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Wed, 1 Oct 2014 11:36:10 +0200 Subject: [PATCH] x86/hvm: improve "Emulation failed @" error messages * Introduce hvm_dump_emulation_state() to be a common implementation rather than having the printk() open-coded slightly differently in 3 separate places. * Identify the vcpu operating mode to allow for unambiguous decoding of the instruction bytes. * A valid instruction can be up to 15 bytes long, but may also be shorter than the current arbitrary 10 bytes. Print only the fetched bytes, which could include nothing if the emulation failed due to an inability to fetch the instruction. A sample new error message looks like: (d1) MMIO emulation failed: d1v0 64bit @ 0008:ffff82d0802c4f20 -> 48 8b b8 e8 7f 00 00 Signed-off-by: Andrew Cooper Reviewed-by: Tim Deegan Release-acked-by: Konrad Rzeszutek Wilk Acked-by: Kevin Tian --- xen/arch/x86/hvm/emulate.c | 36 +++++++++++++++++++++++-------- xen/arch/x86/hvm/io.c | 11 +--------- xen/arch/x86/hvm/vmx/realmode.c | 9 +------- xen/include/asm-x86/hvm/emulate.h | 3 +++ 4 files changed, 32 insertions(+), 27 deletions(-) diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c index 463ccfb418..c0f47d2dfe 100644 --- a/xen/arch/x86/hvm/emulate.c +++ b/xen/arch/x86/hvm/emulate.c @@ -1420,15 +1420,7 @@ void hvm_mem_event_emulate_one(bool_t nowrite, unsigned int trapnr, */ return; case X86EMUL_UNHANDLEABLE: - gdprintk(XENLOG_DEBUG, "Emulation failed @ %04x:%lx: " - "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n", - hvmemul_get_seg_reg(x86_seg_cs, &ctx)->sel, - ctx.insn_buf_eip, - ctx.insn_buf[0], ctx.insn_buf[1], - ctx.insn_buf[2], ctx.insn_buf[3], - ctx.insn_buf[4], ctx.insn_buf[5], - ctx.insn_buf[6], ctx.insn_buf[7], - ctx.insn_buf[8], ctx.insn_buf[9]); + hvm_dump_emulation_state(XENLOG_G_DEBUG "Mem event", &ctx); hvm_inject_hw_exception(trapnr, errcode); break; case X86EMUL_EXCEPTION: @@ -1479,6 +1471,32 @@ struct segment_register *hvmemul_get_seg_reg( return &hvmemul_ctxt->seg_reg[seg]; } +static const char *guest_x86_mode_to_str(int mode) +{ + switch ( mode ) + { + case 0: return "Real"; + case 1: return "v86"; + case 2: return "16bit"; + case 4: return "32bit"; + case 8: return "64bit"; + default: return "Unknown"; + } +} + +void hvm_dump_emulation_state(const char *prefix, + struct hvm_emulate_ctxt *hvmemul_ctxt) +{ + struct vcpu *curr = current; + const char *mode_str = guest_x86_mode_to_str(hvm_guest_x86_mode(curr)); + const struct segment_register *cs = + hvmemul_get_seg_reg(x86_seg_cs, hvmemul_ctxt); + + printk("%s emulation failed: %pv %s @ %04x:%08lx -> %*ph\n", + prefix, curr, mode_str, cs->sel, hvmemul_ctxt->insn_buf_eip, + hvmemul_ctxt->insn_buf_bytes, hvmemul_ctxt->insn_buf); +} + /* * Local variables: * mode: C diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c index e5d5e796ff..68fb89036a 100644 --- a/xen/arch/x86/hvm/io.c +++ b/xen/arch/x86/hvm/io.c @@ -100,16 +100,7 @@ int handle_mmio(void) switch ( rc ) { case X86EMUL_UNHANDLEABLE: - gdprintk(XENLOG_WARNING, - "MMIO emulation failed @ %04x:%lx: " - "%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n", - hvmemul_get_seg_reg(x86_seg_cs, &ctxt)->sel, - ctxt.insn_buf_eip, - ctxt.insn_buf[0], ctxt.insn_buf[1], - ctxt.insn_buf[2], ctxt.insn_buf[3], - ctxt.insn_buf[4], ctxt.insn_buf[5], - ctxt.insn_buf[6], ctxt.insn_buf[7], - ctxt.insn_buf[8], ctxt.insn_buf[9]); + hvm_dump_emulation_state(XENLOG_G_WARNING "MMIO", &ctxt); return 0; case X86EMUL_EXCEPTION: if ( ctxt.exn_pending ) diff --git a/xen/arch/x86/hvm/vmx/realmode.c b/xen/arch/x86/hvm/vmx/realmode.c index 9a6de6c441..fe8b4a032f 100644 --- a/xen/arch/x86/hvm/vmx/realmode.c +++ b/xen/arch/x86/hvm/vmx/realmode.c @@ -157,14 +157,7 @@ static void realmode_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt) return; fail: - gdprintk(XENLOG_ERR, - "Real-mode emulation failed @ %04x:%08lx: " - "%02x %02x %02x %02x %02x %02x\n", - hvmemul_get_seg_reg(x86_seg_cs, hvmemul_ctxt)->sel, - hvmemul_ctxt->insn_buf_eip, - hvmemul_ctxt->insn_buf[0], hvmemul_ctxt->insn_buf[1], - hvmemul_ctxt->insn_buf[2], hvmemul_ctxt->insn_buf[3], - hvmemul_ctxt->insn_buf[4], hvmemul_ctxt->insn_buf[5]); + hvm_dump_emulation_state(XENLOG_G_ERR "Real-mode", hvmemul_ctxt); domain_crash(curr->domain); } diff --git a/xen/include/asm-x86/hvm/emulate.h b/xen/include/asm-x86/hvm/emulate.h index 6cdc57b924..5411302eef 100644 --- a/xen/include/asm-x86/hvm/emulate.h +++ b/xen/include/asm-x86/hvm/emulate.h @@ -54,4 +54,7 @@ int hvmemul_do_pio( unsigned long port, unsigned long *reps, int size, paddr_t ram_gpa, int dir, int df, void *p_data); +void hvm_dump_emulation_state(const char *prefix, + struct hvm_emulate_ctxt *hvmemul_ctxt); + #endif /* __ASM_X86_HVM_EMULATE_H__ */ -- 2.30.2