Re: [kvm-unit-tests PATCH v2 3/3] s390x: mvpg: Add SIE mvpg test

[Thomas Huth <thuth@redhat.com>]

On 29/06/2021 15.18, Janosch Frank wrote:
> Let's also check the PEI values to make sure our VSIE implementation
> is correct.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>   s390x/Makefile                  |   2 +
>   s390x/mvpg-sie.c                | 151 ++++++++++++++++++++++++++++++++
>   s390x/snippets/c/mvpg-snippet.c |  33 +++++++
>   s390x/unittests.cfg             |   3 +
>   4 files changed, 189 insertions(+)
>   create mode 100644 s390x/mvpg-sie.c
>   create mode 100644 s390x/snippets/c/mvpg-snippet.c
> 
> diff --git a/s390x/Makefile b/s390x/Makefile
> index ba32f4c..07af26d 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -23,6 +23,7 @@ tests += $(TEST_DIR)/sie.elf
>   tests += $(TEST_DIR)/mvpg.elf
>   tests += $(TEST_DIR)/uv-host.elf
>   tests += $(TEST_DIR)/edat.elf
> +tests += $(TEST_DIR)/mvpg-sie.elf
>   
>   tests_binary = $(patsubst %.elf,%.bin,$(tests))
>   ifneq ($(HOST_KEY_DOCUMENT),)
> @@ -82,6 +83,7 @@ snippet_asmlib = $(SNIPPET_DIR)/c/cstart.o
>   
>   # perquisites (=guests) for the snippet hosts.
>   # $(TEST_DIR)/<snippet-host>.elf: snippets = $(SNIPPET_DIR)/<c/asm>/<snippet>.gbin
> +$(TEST_DIR)/mvpg-sie.elf: snippets = $(SNIPPET_DIR)/c/mvpg-snippet.gbin
>   
>   $(SNIPPET_DIR)/asm/%.gbin: $(SNIPPET_DIR)/asm/%.o $(FLATLIBS)
>   	$(OBJCOPY) -O binary $(patsubst %.gbin,%.o,$@) $@
> diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
> new file mode 100644
> index 0000000..3536c6a
> --- /dev/null
> +++ b/s390x/mvpg-sie.c
> @@ -0,0 +1,151 @@
> +#include <libcflat.h>
> +#include <asm/asm-offsets.h>
> +#include <asm-generic/barrier.h>
> +#include <asm/pgtable.h>
> +#include <mmu.h>
> +#include <asm/page.h>
> +#include <asm/facility.h>
> +#include <asm/mem.h>
> +#include <alloc_page.h>
> +#include <vm.h>
> +#include <sclp.h>
> +#include <sie.h>
> +
> +static u8 *guest;
> +static u8 *guest_instr;
> +static struct vm vm;
> +
> +static uint8_t *src;
> +static uint8_t *dst;
> +static uint8_t *cmp;
> +
> +extern const char _binary_s390x_snippets_c_mvpg_snippet_gbin_start[];
> +extern const char _binary_s390x_snippets_c_mvpg_snippet_gbin_end[];
> +int binary_size;
> +
> +static void sie(struct vm *vm)
> +{
> +	/* Reset icptcode so we don't trip over it below */
> +	vm->sblk->icptcode = 0;
> +
> +	while (vm->sblk->icptcode == 0) {
> +		sie64a(vm->sblk, &vm->save_area);
> +		if (vm->sblk->icptcode == ICPT_VALIDITY)
> +			assert(0);

Please replace the above two lines with:

		assert(vm->sblk->icptcode != ICPT_VALIDITY);

> +	}
> +	vm->save_area.guest.grs[14] = vm->sblk->gg14;
> +	vm->save_area.guest.grs[15] = vm->sblk->gg15;
> +}
> +
> +static void test_mvpg_pei(void)
> +{
> +	uint64_t **pei_dst = (uint64_t **)((uintptr_t) vm.sblk + 0xc0);
> +	uint64_t **pei_src = (uint64_t **)((uintptr_t) vm.sblk + 0xc8);
> +
> +	report_prefix_push("pei");
> +
> +	report_prefix_push("src");
> +	memset(dst, 0, PAGE_SIZE);
> +	protect_page(src, PAGE_ENTRY_I);
> +	sie(&vm);
> +	report(vm.sblk->icptcode == ICPT_PARTEXEC, "Partial execution");
> +	report((uintptr_t)**pei_src == (uintptr_t)src + PAGE_ENTRY_I, "PEI_SRC correct");
> +	report((uintptr_t)**pei_dst == (uintptr_t)dst, "PEI_DST correct");
> +	unprotect_page(src, PAGE_ENTRY_I);
> +	report(!memcmp(cmp, dst, PAGE_SIZE), "Destination intact");
> +	/*
> +	 * We need to execute the diag44 which is used as a blocker
> +	 * behind the mvpg. It makes sure we fail the tests above if
> +	 * the mvpg wouldn't have intercepted.
> +	 */
> +	sie(&vm);
> +	/* Make sure we intercepted for the diag44 and nothing else */
> +	assert(vm.sblk->icptcode == ICPT_INST &&
> +	       vm.sblk->ipa == 0x8300 && vm.sblk->ipb == 0x440000);
> +	report_prefix_pop();
> +
> +	/* Clear PEI data for next check */
> +	report_prefix_push("dst");
> +	memset((uint64_t *)((uintptr_t) vm.sblk + 0xc0), 0, 16);
> +	memset(dst, 0, PAGE_SIZE);
> +	protect_page(dst, PAGE_ENTRY_I);
> +	sie(&vm);
> +	report(vm.sblk->icptcode == ICPT_PARTEXEC, "Partial execution");
> +	report((uintptr_t)**pei_src == (uintptr_t)src, "PEI_SRC correct");
> +	report((uintptr_t)**pei_dst == (uintptr_t)dst + PAGE_ENTRY_I, "PEI_DST correct");
> +	/* Needed for the memcmp and general cleanup */
> +	unprotect_page(dst, PAGE_ENTRY_I);
> +	report(!memcmp(cmp, dst, PAGE_SIZE), "Destination intact");
> +	report_prefix_pop();
> +
> +	report_prefix_pop();
> +}

Still quite a lot of magic values in above code ... any chance to introduce 
some #defines finally?

> +static void test_mvpg(void)
> +{
> +	int binary_size = ((uintptr_t)_binary_s390x_snippets_c_mvpg_snippet_gbin_end -
> +			   (uintptr_t)_binary_s390x_snippets_c_mvpg_snippet_gbin_start);
> +
> +	memcpy(guest, _binary_s390x_snippets_c_mvpg_snippet_gbin_start, binary_size);
> +	memset(src, 0x42, PAGE_SIZE);
> +	memset(dst, 0x43, PAGE_SIZE);
> +	sie(&vm);
> +	mb();

I think you don't need the mb() here.

> +	report(!memcmp(src, dst, PAGE_SIZE) && *dst == 0x42, "Page moved");
> +}

  Thomas