Re: [PATCH for-4.16 3/4] test/tsx: set grant version for created domains

[Andrew Cooper <amc96@xxxxxxxx>]

On 15/11/2021 12:17, Roger Pau Monne wrote:
> Set the grant table version for the created domains to use version 1,
> as such tests domains don't require the usage of the grant table at
> all. A TODO note is added to switch those dummy domains to not have a
> grant table at all when possible. Without setting the grant version
> the domains for the tests cannot be created.
>
> Fixes: 7379f9e10a ('gnttab: allow setting max version per-domain')
> Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reported-by: Jan Beulich <jbeulich@xxxxxxxx>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> ---
> Cc: Ian Jackson <iwj@xxxxxxxxxxxxxx>
>
> This patch only modifies a test, so it should be safe to commit as
> it's not going to cause any changes to the hypervisor or the tools.
> Worse that could happen is it makes the test even more broken, but
> it's already unusable.

What do you mean unusable?  Other than this, the test works.

> ---
>  tools/tests/tsx/test-tsx.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/tools/tests/tsx/test-tsx.c b/tools/tests/tsx/test-tsx.c
> index fab99c135e..f1dcff4c30 100644
> --- a/tools/tests/tsx/test-tsx.c
> +++ b/tools/tests/tsx/test-tsx.c
> @@ -444,6 +444,8 @@ static void test_guests(void)
>          struct xen_domctl_createdomain c = {
>              .max_vcpus = 1,
>              .max_grant_frames = 1,
> +            /* TODO: switch to 0 once support for no grant table is added. */

I'd avoid these TODOs.  It's test code, so really doesn't matter too much.

However, there is a further task for this test to actually boot enough
of a guest to dump CPUID as visible inside the guest, and cross-check
with the toolstack's view of the data.

How exactly to get that data out of the VM is an open question, but it
might involve xenconsoled.

~Andrew