Re: [Qemu-devel] memtest 4.20+ does not work with -cpu host

[Peter Lieven]

On 09/10/12 14:21, Gleb Natapov wrote:
> On Mon, Sep 10, 2012 at 02:15:49PM +0200, Paolo Bonzini wrote:
> > Il 10/09/2012 13:52, Peter Lieven ha scritto:
> > > > dd if=/dev/cpu/0/msr skip=$((0x194)) bs=8 count=1 | xxd
> > > > dd if=/dev/cpu/0/msr skip=$((0xCE)) bs=8 count=1 | xxd
> > > it only works without the skip. but the msr device returns all zeroes.
> > Hmm, the strange API of the MSR device doesn't work well with dd (dd
> > skips to 0x194 * 8 because bs is 8.  You can try this program:
> There is rdmsr/wrmsr in msr-tools.
rdmsr returns it cannot read those MSRs. regardless if I use -cpu host 
or -cpu qemu64.

peter
> > #include<fcntl.h>
> > #include<stdio.h>
> > #include<stdlib.h>
> >
> > int rdmsr(int fd, long reg)
> > {
> >      char msg[40];
> >      long long val;
> >      sprintf(msg, "rdmsr(%#x)", reg);
> >      if (pread(fd,&val, 8, reg)<  0) {
> >          perror(msg);
> >      } else {
> >          printf("%s: %#016llx\n", msg, val);
> >          fflush(stdout);
> >      }
> > }
> >
> >
> > int main()
> > {
> >      int fd = open("/dev/cpu/0/msr", O_RDONLY);
> >      if (fd<  0) { perror("open"); exit(1); }
> >      rdmsr(fd, 0x194);
> >      rdmsr(fd, 0xCE);
> > }
> >
> > Paolo
> > --
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> --
>                         Gleb.