Re: [kvm-unit-tests PATCH v3 6/6] s390x: add a test for SIE without MSO/MSL

Nico Boehr
2023-07-10T14:29:44Z

Quoting Janosch Frank (2023-06-05 11:57:58)
[...]
> > diff --git a/s390x/sie-dat.c b/s390x/sie-dat.c
> > new file mode 100644
> > index 000000000000..c490a2aa825c
[...]
> > +#include <libcflat.h>
> > +#include <vmalloc.h>
> > +#include <asm/asm-offsets.h>
>
> I only did a cursory glance and wasn't able to see a use for this include.

Yep, thanks, I cleaned up the includes a bit.

[...]
> > +static void test_sie_dat(void)
> > +{
> > + uint8_t r1;
> > + bool contents_match;
> > + uint64_t test_page_gpa, test_page_hpa;
> > + uint8_t *test_page_hva;
> > +
> > + /* guest will tell us the guest physical address of the test buffer */
> > + sie(&vm);
> > +
> > + r1 = (vm.sblk->ipa & 0xf0) >> 4;
> > + test_page_gpa = vm.save_area.guest.grs[r1];
> > + test_page_hpa = virt_to_pte_phys(guest_root, (void*)test_page_gpa);
> > + test_page_hva = __va(test_page_hpa);
> > + report(vm.sblk->icptcode == ICPT_INST &&
> > + (vm.sblk->ipa & 0xFF00) == 0x8300 && vm.sblk->ipb == 0x9c0000,
> > + "test buffer gpa=0x%lx hva=%p", test_page_gpa, test_page_hva);
>
> You could rebase on my pv_icptdata.h patch.
> Also the report string and boolean don't really relate to each other.

Which patch are we talking about? pv_icptdata_check_diag()?

Note that this is not a PV test, so I guess it's not applicable here?

> Not every exit needs to be a report.
> Some should rather be asserts() or report_info()s.

Yeah, I have made report()s where it doesn't make sense to continue assert()s

> > + contents_match = true;
> > + for (unsigned int i = 0; i < GUEST_TEST_PAGE_COUNT; i++) {
> > + uint8_t expected_val = 42 + i;
>
> Just because you can doesn't mean that you have to.
> At least leave a \n when declaring new variables...

I am a bit confused but I *guess* you wanted me to move the declaration of
expected_val to the beginning of the function?

[...]
> > diff --git a/s390x/snippets/c/sie-dat.c b/s390x/snippets/c/sie-dat.c
> > new file mode 100644
> > index 000000000000..e156d0c36c4c
> > --- /dev/null
> > +++ b/s390x/snippets/c/sie-dat.c
> > @@ -0,0 +1,58 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Snippet used by the sie-dat.c test to verify paging without MSO/MSL
> > + *
> > + * Copyright (c) 2023 IBM Corp
> > + *
> > + * Authors:
> > + * Nico Boehr <nrb@linux.ibm.com>
> > + */
> > +#include <stddef.h>
> > +#include <inttypes.h>
> > +#include <string.h>
> > +#include <asm-generic/page.h>
> > +
> > +/* keep in sync with GUEST_TEST_PAGE_COUNT in s390x/sie-dat.c */
> > +#define TEST_PAGE_COUNT 10
> > +static uint8_t test_page[TEST_PAGE_COUNT * PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
> > +
> > +/* keep in sync with GUEST_TOTAL_PAGE_COUNT in s390x/sie-dat.c */
> > +#define TOTAL_PAGE_COUNT 256
> > +
> > +static inline void force_exit(void)
> > +{
> > + asm volatile("diag 0,0,0x44\n");
> > +}
> > +
> > +static inline void force_exit_value(uint64_t val)
> > +{
> > + asm volatile(
> > + "diag %[val],0,0x9c\n"
> > + : : [val] "d"(val)
> > + );
> > +}
>
> It feels like these need to go into a snippet lib.

A bunch of other tests do similar things, so I'll write a TODO and tackle it in
a seperate series.

[...]
> > +
> > +__attribute__((section(".text"))) int main(void)
>
> The attribute shouldn't be needed anymore.

OK, removed.

[...]
> > +{
> > + uint8_t *invalid_ptr;
> > +
> > + memset(test_page, 0, sizeof(test_page));
> > + /* tell the host the page's physical address (we're running DAT off) */
> > + force_exit_value((uint64_t)test_page);
> > +
> > + /* write some value to the page so the host can verify it */
> > + for (size_t i = 0; i < TEST_PAGE_COUNT; i++)
>
> Why is i a size_t type?

Because it's a suitable unsigned type for use as an array index.

What should it be instead?