Aurelien Jarno wrote: > On Fri, Jul 20, 2007 at 09:57:55AM +0300, Avi Kivity wrote: > >> Avi Kivity wrote: >> >>>> Please tell me what I can do to help debugging this problem. >>>> Alternatively I have uploaded an image to reproduce the problem here: >>>> http://temp.aurel32.net/kfreebsd-amd64.img.g >>>> >>>> >>> I've downloaded the image and booted it three times using kvm HEAD. >>> Each time I got to the login prompt. >>> >>> Is this always reproducible? Can you check with kvm HEAD (not that I >>> think of anything that could have fixed this). >>> >>> >>> >> Sorry, that was on Intel. It reproduces easily on AMD. >> > > By comparing the cases were the old and the new condition are different, > I have found that the problem occurs for the lmsw and smsw instructions. >
Ah, I was looking at amd-specific instructions (vmx decodes lmsw) but missed these two. Good work. > The patch below is very ugly, but it workarounds the problem. > It's not ugly, it just lives in an ugly function. But it does lack a changelog and a signoff. As to the ugliness, prehaps no_wb should be part of the opcode descriptor bitmask (opcode_table and friend). > diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c > index 21ce977..6c1523f 100644 > --- a/drivers/kvm/x86_emulate.c > +++ b/drivers/kvm/x86_emulate.c > @@ -1206,11 +1206,13 @@ twobyte_insn: > goto cannot_emulate; > *(u16 *)&_regs[modrm_rm] > = realmode_get_cr(ctxt->vcpu, 0); > + no_wb = 1; > break; > case 6: /* lmsw */ > if (modrm_mod != 3) > goto cannot_emulate; > realmode_lmsw(ctxt->vcpu, (u16)modrm_val, &_eflags); > + no_wb = 1; > break; > case 7: /* invlpg*/ > > -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
