On Mon, Jul 18, 2016 at 11:26:50AM -0400, Paolo Bonzini wrote:

quoted

Indeed, ignore_msrs does a completely different thing.  It suppresses
general protection faults in the guest.  It is related to behavior that
KVM injects in the guests, not to the things that KVM spews in the host.

What about just downgrading the printf to KERN_DEBUG?  You could simply
change from vcpu_unimpl to vcpu_debug, but it's probably a good idea to
keep the ratelimiting; there's a kvm_pr_unimpl, so maybe add a new
kvm_pr_debug and vcpu_pr_debug.

Hm, we've certainly got a lot of options in terms of print primitives these
days.

We could just do this...

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 1c9c973a7dd9..a80b9a0a5f8c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h

@@ -423,7 +423,7 @@ struct kvm {
 #define kvm_debug(fmt, ...) \
        pr_debug("kvm [%i]: " fmt, task_pid_nr(current), ## __VA_ARGS__)
 #define kvm_pr_unimpl(fmt, ...) \
-       pr_err_ratelimited("kvm [%i]: " fmt, \
+       pr_debug_ratelimited("kvm [%i]: " fmt, \
                           task_tgid_nr(current), ## __VA_ARGS__)
 
 /* The guest did something we don't support. */

Which I think would have the desired effect, and also gets us dynamic debug
support for free.