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

[Janosch Frank <frankja@linux.ibm.com>]

On 7/5/21 9:24 AM, Thomas Huth wrote:
> 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);

Sure

> 
>> +	}
>> +	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?

Currently not really.
I added a comment for the diag 44 which should be enough right now. If
needed I can add a comment to the pei variables as well.

> 
>> +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.

Right

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