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

Sean Christopherson
2021-10-18T18:39:37Z

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(-)

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2.33.0.1079.g6e70778dc9-goog