Re: [PATCH] KVM: x86: use positive error values for msr emulation that causes #GP

[Paolo Bonzini]

On 04/11/20 17:31, Qian Cai wrote:
> On Sun, 2020-11-01 at 13:55 +0200, Maxim Levitsky wrote:
> > Recent introduction of the userspace msr filtering added code that uses
> > negative error codes for cases that result in either #GP delivery to
> > the guest, or handled by the userspace msr filtering.
> >
> > This breaks an assumption that a negative error code returned from the
> > msr emulation code is a semi-fatal error which should be returned
> > to userspace via KVM_RUN ioctl and usually kill the guest.
> >
> > Fix this by reusing the already existing KVM_MSR_RET_INVALID error code,
> > and by adding a new KVM_MSR_RET_FILTERED error code for the
> > userspace filtered msrs.
> >
> > Fixes: 291f35fb2c1d1 ("KVM: x86: report negative values from wrmsr emulation
> > to userspace")
> > Reported-by: Qian Cai <cai@xxxxxxxxxx>
> > Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
> Apparently, it does not apply cleanly on today's linux-next. Paolo, is it
> possible to toss this into -next soon, so our CI won't be blocked because of
> this bug?

Yep, I plan to send it to Linus later this week.

Paolo