Re: [PATCH 0/2] KVM: x86: Enhance vendor module error messages

Paolo Bonzini
2021-10-20T14:56:05Z

On 18/10/21 20:39, Sean Christopherson wrote:
> Paul Menzel encountered the bad userspace behavior of spamming KVM module
> loading on all CPUs, which was mitigated by commit ef935c25fd64 ("kvm: x86:
> Limit the number of "kvm: disabled by bios" messages"), except this time
> userspace is extra "clever" and spams both kvm_intel and kvm_amd. Because
> the "already loaded the other module" message isn't ratelimited, the bogus
> module load managed to spam the kernel log.
>
> Patch 1 addresses another suggestion from Paul by incorporating the vendor
> module name into the error messages.
>
> Patch 2 addresses the original report by prioritizing the hardware/bios
> support messages over the "already loaded" error. In additional to
> reducing spam, doing so also ensures consistent messaging if a vendor
> module isn't supported regardless of what other modules may be loaded.
>
> [*] https://lkml.kernel.org/r/20210818114956.7171-1-pmenzel@molgen.mpg.de
>
> Sean Christopherson (2):
> KVM: x86: Add vendor name to kvm_x86_ops, use it for error messages
> KVM: x86: Defer "already loaded" check until after basic support
> checks
>
> arch/x86/include/asm/kvm_host.h | 2 ++
> arch/x86/kvm/svm/svm.c | 2 ++
> arch/x86/kvm/vmx/vmx.c | 2 ++
> arch/x86/kvm/x86.c | 17 +++++++++--------
> 4 files changed, 15 insertions(+), 8 deletions(-)
>

Queued, thanks. But I kept the ratelimiting; given the recent "clashes"
with the chief penguin, I am also ratelimiting the snark in the commit
messages.

Paolo