Re: [PATCH v3 2/2] KVM: selftests: Test that KVM_RUN fails for unresolvable host faults

[Sean Christopherson <seanjc@google.com>]

On Tue, Oct 27, 2026, Christian Borntraeger wrote:
> Am 23.10.26 um 17:06 schrieb Sean Christopherson:
> > On Fri, Oct 23, 2026, Christian Borntraeger wrote:
> > > Add a test in which the guest writes to a shmem-backed memslot beyond
> > > the end of the file.  KVM_RUN must fail with -EFAULT.
> > > 
> > > On x86 the guest enables interrupts, and on s390 the test sets up
> > > pfault, so that KVM could handle the fault with an asynchronous page
> > > fault.  If KVM mistakes the error for a fault that needs I/O, the vCPU
> > > retries the access forever, and the test fails after a timeout.
> > > 
> > > The test is not built for LoongArch, which handles a failed mapping as
> > > an MMIO access.
> > > 
> > > Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> > > ---
> > > I went with Seans name proposal
> > 
> > Aww, bummer.  If you posted a faulty_mcfault_face_test, I would absolutely apply
> > that and force Paolo to tell me no :-)
> 
> Sean,
> Will you pick up the fix and the selftest, shall I do it or Paolo directly?

I can grab 'em.  Were you hoping to get the fix into 7.4?  It doesn't seem super
urgent?  I was leaning towards waiting for 7.5, but tagging it for stable@.  I.e.
give ourselves a full cycle to make sure we didn't miss something, then get the
fix backported because I wouldn't be surprised if people are hitting this in
production without realizing it.