Re: memtest 4.20+ does not work with -cpu host

[Peter Lieven <pl@dlhnet.de>]

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.