Re: [kvm-unit-tests RFC 2/2] s390x: mvpg: Add SIE mvpg test

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Thu, 20 May 2021 09:47:30 +0000
Janosch Frank <frankja@linux.ibm.com> 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                  |   3 +-
>  s390x/mvpg-sie.c                | 139
> ++++++++++++++++++++++++++++++++ s390x/snippets/c/mvpg-snippet.c |
> 33 ++++++++ s390x/unittests.cfg             |   3 +
>  4 files changed, 177 insertions(+), 1 deletion(-)
>  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 fe267011..6692cf73 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -22,6 +22,7 @@ tests += $(TEST_DIR)/uv-guest.elf
>  tests += $(TEST_DIR)/sie.elf
>  tests += $(TEST_DIR)/mvpg.elf
>  tests += $(TEST_DIR)/uv-host.elf
> +tests += $(TEST_DIR)/mvpg-sie.elf
>  
>  tests_binary = $(patsubst %.elf,%.bin,$(tests))
>  ifneq ($(HOST_KEY_DOCUMENT),)
> @@ -79,7 +80,7 @@ FLATLIBS = $(libcflat)
>  SNIPPET_DIR = $(TEST_DIR)/snippets
>  
>  # C snippets that need to be linked
> -snippets-c =
> +snippets-c = $(SNIPPET_DIR)/c/mvpg-snippet.gbin
>  
>  # ASM snippets that are directly compiled and converted to a *.gbin
>  snippets-a =
> diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
> new file mode 100644
> index 00000000..a617704b
> --- /dev/null
> +++ b/s390x/mvpg-sie.c
> @@ -0,0 +1,139 @@
> +#include <libcflat.h>
> +#include <asm/asm-offsets.h>
> +#include <asm-generic/barrier.h>
> +#include <asm/interrupt.h>
> +#include <asm/pgtable.h>
> +#include <mmu.h>
> +#include <asm/page.h>
> +#include <asm/facility.h>
> +#include <asm/mem.h>
> +#include <asm/sigp.h>
> +#include <smp.h>
> +#include <alloc_page.h>
> +#include <bitops.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;
> +
> +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 handle_validity(struct vm *vm)
> +{
> +	report(0, "VALIDITY: %x", vm->sblk->ipb >> 16);

I think an assert would be better. This should not happen, and if it
happens something went very wrong and we have no guarantee that we will
be able to continue

> +}
> +
> +static void sie(struct vm *vm)
> +{
> +	/* Reset icptcode so we don't trip below */
> +	vm->sblk->icptcode = 0;
> +
> +	while (vm->sblk->icptcode == 0) {
> +		sie64a(vm->sblk, &vm->save_area);
> +		if (vm->sblk->icptcode == ICPT_VALIDITY)
> +			handle_validity(vm);
> +	}
> +	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");

maybe clear the destination buffer...

> +	protect_page(guest + 0x6000, PAGE_ENTRY_I);
> +	sie(&vm);
> +	report(vm.sblk->icptcode == ICPT_PARTEXEC, "Partial
> execution");
> +	report((uintptr_t)**pei_src == ((uintptr_t)vm.sblk->mso) +
> 0x6000 + PAGE_ENTRY_I, "PEI_SRC correct");
> +	report((uintptr_t)**pei_dst == vm.sblk->mso + 0x5000,
> "PEI_DST correct");

... and check that the page was not copied

> +	/* Jump over the diag44 */
> +	sie(&vm);

I would check if you really got a diag44

> +	/* Clear PEI data for next check */
> +	memset((uint64_t *)((uintptr_t) vm.sblk + 0xc0), 0, 16);
> +	unprotect_page(guest + 0x6000, PAGE_ENTRY_I);
> +	protect_page(guest + 0x5000, PAGE_ENTRY_I);
> +	sie(&vm);
> +	report(vm.sblk->icptcode == ICPT_PARTEXEC, "Partial
> execution");
> +	report((uintptr_t)**pei_src == vm.sblk->mso + 0x6000,
> "PEI_SRC correct");
> +	report((uintptr_t)**pei_dst == vm.sblk->mso + 0x5000 +
> PAGE_ENTRY_I, "PEI_DST correct"); +
> +	report_prefix_pop();
> +}
> +
> +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();
> +	report(!memcmp(src, dst, PAGE_SIZE) && *dst == 0x42, "Page

or maybe you can clear the destination buffer here, if you prefer

> moved"); +}
> +
> +static void setup_guest(void)
> +{
> +	setup_vm();
> +
> +	/* Allocate 1MB as guest memory */
> +	guest = alloc_pages(8);
> +	/* The first two pages are the lowcore */
> +	guest_instr = guest + PAGE_SIZE * 2;
> +
> +	vm.sblk = alloc_page();
> +
> +	vm.sblk->cpuflags = CPUSTAT_ZARCH | CPUSTAT_RUNNING;
> +	vm.sblk->prefix = 0;
> +	/*
> +	 * Pageable guest with the same ASCE as the test programm,
> but
> +	 * the guest memory 0x0 is offset to start at the allocated
> +	 * guest pages and end after 1MB.
> +	 *
> +	 * It's not pretty but faster and easier than managing guest
> ASCEs.
> +	 */
> +	vm.sblk->mso = (u64)guest;
> +	vm.sblk->msl = (u64)guest;
> +	vm.sblk->ihcpu = 0xffff;
> +
> +	vm.sblk->crycbd = (uint64_t)alloc_page();
> +
> +	vm.sblk->gpsw.addr = PAGE_SIZE * 4;
> +	vm.sblk->gpsw.mask = 0x0000000180000000ULL;
> +	vm.sblk->ictl = ICTL_OPEREXC | ICTL_PINT;
> +	/* Enable MVPG interpretation as we want to test KVM and not
> ourselves */
> +	vm.sblk->eca = ECA_MVPGI;
> +
> +	src = guest + PAGE_SIZE * 6;
> +	dst = guest + PAGE_SIZE * 5;
> +}
> +
> +int main(void)
> +{
> +	report_prefix_push("mvpg-sie");
> +	if (!sclp_facilities.has_sief2) {
> +		report_skip("SIEF2 facility unavailable");
> +		goto done;
> +	}
> +
> +	setup_guest();
> +	test_mvpg();
> +	test_mvpg_pei();
> +
> +done:
> +	report_prefix_pop();
> +	return report_summary();
> +
> +}
> diff --git a/s390x/snippets/c/mvpg-snippet.c
> b/s390x/snippets/c/mvpg-snippet.c new file mode 100644
> index 00000000..96b70c9c
> --- /dev/null
> +++ b/s390x/snippets/c/mvpg-snippet.c
> @@ -0,0 +1,33 @@
> +#include <libcflat.h>
> +
> +static inline void force_exit(void)
> +{
> +	asm volatile("	diag	0,0,0x44\n");
> +}
> +
> +static inline int mvpg(unsigned long r0, void *dest, void *src)
> +{
> +	register unsigned long reg0 asm ("0") = r0;
> +	int cc;
> +
> +	asm volatile("	mvpg    %1,%2\n"
> +		     "	ipm     %0\n"
> +		     "	srl     %0,28"
> +		     : "=&d" (cc) : "a" (dest), "a" (src), "d" (reg0)
> +		     : "memory", "cc");
> +	return cc;
> +}
> +
> +static void test_mvpg_real(void)
> +{
> +	mvpg(0, (void *)0x5000, (void *)0x6000);
> +	force_exit();
> +}
> +
> +__attribute__((section(".text"))) int main(void)
> +{
> +	test_mvpg_real();
> +	test_mvpg_real();
> +	test_mvpg_real();
> +	return 0;
> +}
> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
> index 9f81a608..8634b1b1 100644
> --- a/s390x/unittests.cfg
> +++ b/s390x/unittests.cfg
> @@ -103,3 +103,6 @@ file = sie.elf
>  [mvpg]
>  file = mvpg.elf
>  timeout = 10
> +
> +[mvpg-sie]
> +file = mvpg-sie.elf