Hello and thanks for the patch. Aside from indent issues (please use
tabs, Linux kernel style), I have some comments/questions:
On 02/24/2015 09:27 AM, Wei,Jiangang wrote:
> KVM guest is on top of QEMU, It's necessary that figure out
> the difference between the two.
>
> Signed-off-by: Wei,Jiangang <weijg.f...@cn.fujitsu.com>
> ---
> lib/tst_virt.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/lib/tst_virt.c b/lib/tst_virt.c
> index eb3b487..1d9960e 100644
> --- a/lib/tst_virt.c
> +++ b/lib/tst_virt.c
> @@ -100,14 +100,24 @@ static int is_kvm(void)
> FILE *cpuinfo;
> char line[64];
> int found;
> + char sig[SIG_MAX_LEN];
>
> - /* this doesn't work with custom -cpu values, since there's
> - * no easy, reasonable or reliable way to work around those */
When writing this, I was well aware of virt-what, which is exactly
why I wrote that comment the way I did - the code used by virt-what
is not easy, reliable or (IMO) reasonable to copy/paste into LTP.
Specifically with kvm, the KVMKVMKVM detection used to fail (IIRC)
with some specific hosts and qemu versions. It can also be easily
bypassed with -cpu host,kvm=off (which doesn't disable kvm accel).
> cpuinfo = SAFE_FOPEN(NULL, "/proc/cpuinfo", "r");
> found = 0;
> while (fgets(line, sizeof(line), cpuinfo) != NULL) {
> if (strstr(line, "QEMU Virtual CPU")) {
> - found = 1;
> + /*
> + * Is it an KVM(on top of QEMU) or Only a QEMU?
> + */
Well, yes, I'm aware that "KVM" is really just QEMU + accel, which
is why my original series actually had VIRT_QEMU instead of VIRT_KVM,
but then it was pointed out to me that VIRT_KVM would make sense to
most people not knowledgeable enough in this area.
I'm not against renaming it, but I'm a bit baffled by the separation.
> + if (cpu_sign(&sig[0]) == 0) {
> + if (strcmp(sig, "KVMKVMKVM") == 0) {
> + found = 1;
> + } else {
> + // QEMU Guest
This leads me to ask why did you create the patches - why should the
default QEMU with TCG be any different w.r.t. the only test that
currently uses the tst_is_virt() function?
Again, I'm not against renaming VIRT_KVM to VIRT_QEMU as it would be
technically more correct, but why separate accel=kvm from accel=tcg?
What about accel=xen?
> + }
> + } else {
> + found = 1;
> + }
> break;
> }
> }
>
Thanks,
Jiri
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