Re: [PATCH v4 19/19] KVM: selftests: Add test for KVM_SET_USER_MEMORY_REGION

[Sean Christopherson]

On Wed, Dec 18, 2019 at 12:39:43PM +0100, Christian Borntraeger wrote:
> 
> On 17.12.19 21:40, Sean Christopherson wrote:
> > Add a KVM selftest to test moving the base gfn of a userspace memory
> > region.  The test is primarily targeted at x86 to verify its memslot
> > metadata is correctly updated, but also provides basic functionality
> > coverage on other architectures.
> > +static void *vcpu_worker(void *data)
> > +{
> > +	struct kvm_vm *vm = data;
> > +	struct kvm_run *run;
> > +	struct ucall uc;
> > +	uint64_t cmd;
> > +
> > +	/*
> > +	 * Loop until the guest is done.  Re-enter the guest on all MMIO exits,
> > +	 * which will occur if the guest attempts to access a memslot while it
> > +	 * is being moved.
> > +	 */
> > +	run = vcpu_state(vm, VCPU_ID);
> > +	do {
> > +		vcpu_run(vm, VCPU_ID);
> > +	} while (run->exit_reason == KVM_EXIT_MMIO);
> > +
> > +	TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
> > +		    "Unexpected exit reason = %d", run->exit_reason);
> 
> 
> This will also not work for s390. Maybe just make this test x86 specific for now?

Doh, that's obvious in hindsight.  I think the basic premise is also
broken on arm64 as it returns -EFAULT on is_error_noslot_pfn(pfn).  So
yeah, x86 only for now :-(