Hi,
On Tue, Mar 08, 2022 at 05:31:25PM +0000, Andre Przywara wrote:
> On Sat, 26 Feb 2022 14:00:48 +0800
> Dongli Si <sidongli1997@xxxxxxxxx> wrote:
>
> Hi,
>
> > From: Dongli Si <sidongli1997@xxxxxxxxx>
> >
> > glibc detected invalid CPU Vendor name will cause an error:
> >
> > [ 0.450127] Run /sbin/init as init process
> > /lib64/libc.so.6: CPU ISA level is lower than required
> > [ 0.451931] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00007f00
> > [ 0.452117] CPU: 0 PID: 1 Comm: init Not tainted 5.17.0-rc1 #72
> >
> > Signed-off-by: Dongli Si <sidongli1997@xxxxxxxxx>
> > ---
> > x86/cpuid.c | 14 +++++++++-----
> > 1 file changed, 9 insertions(+), 5 deletions(-)
> >
> > diff --git a/x86/cpuid.c b/x86/cpuid.c
> > index c3b67d9..d58a027 100644
> > --- a/x86/cpuid.c
> > +++ b/x86/cpuid.c
> > @@ -2,6 +2,7 @@
> >
> > #include "kvm/kvm.h"
> > #include "kvm/util.h"
> > +#include "kvm/cpufeature.h"
> >
> > #include <sys/ioctl.h>
> > #include <stdlib.h>
> > @@ -10,7 +11,7 @@
> >
> > static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid)
> > {
> > - unsigned int signature[3];
> > + struct cpuid_regs regs;
> > unsigned int i;
> >
> > /*
> > @@ -22,10 +23,13 @@ static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid)
> > switch (entry->function) {
> > case 0:
> > /* Vendor name */
> > - memcpy(signature, "LKVMLKVMLKVM", 12);
> > - entry->ebx = signature[0];
> > - entry->ecx = signature[1];
> > - entry->edx = signature[2];
> > + regs = (struct cpuid_regs) {
> > + .eax = 0x00,
> > + };
> > + host_cpuid(®s);
> > + entry->ebx = regs.ebx;
> > + entry->ecx = regs.ecx;
> > + entry->edx = regs.edx;
>
> But that's redundant, isn't it? We already get the host vendor ID in the
> three registers in entry, and the current code is just there to overwrite
> this. So just removing the whole "case 0:" part should do the trick.
>
> Also please be aware that there was a reason for this fixup, as explained
> in commit bc0b99a2a740 ("kvm tools: Filter out CPU vendor string").
>
> Alex, did you boot this on an AMD box, to spot if this is still an issue?
I did a boot on an AMD Ryzen 3900x, didn't find any issues. But I don't
think a sample of one CPU is representative, so I'm not sure if the error
will not manifest with other models which exist now, or be released in the
future.
