[kvm-unit-tests GIT PULL 12/12] s390x: edat test

Janosch Frank
2021-06-22T08:21:52Z

Simple EDAT test.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20210611140705.553307-8-imbrenda@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
s390x/Makefile | 1 +
s390x/edat.c | 274 ++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
3 files changed, 278 insertions(+)
create mode 100644 s390x/edat.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 8de926ab..8820e998 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)/edat.elf

tests_binary = $(patsubst %.elf,%.bin,$(tests))
ifneq ($(HOST_KEY_DOCUMENT),)
diff --git a/s390x/edat.c b/s390x/edat.c
new file mode 100644
index 00000000..c3bee0c8
--- /dev/null
+++ b/s390x/edat.c
@@ -0,0 +1,274 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * EDAT test.
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ * Claudio Imbrenda <imbrenda@linux.ibm.com>
+ */
+#include <libcflat.h>
+#include <vmalloc.h>
+#include <asm/facility.h>
+#include <asm/interrupt.h>
+#include <mmu.h>
+#include <asm/pgtable.h>
+#include <asm-generic/barrier.h>
+
+#define PGD_PAGE_SHIFT (REGION1_SHIFT - PAGE_SHIFT)
+
+#define LC_SIZE (2 * PAGE_SIZE)
+#define VIRT(x) ((void *)((unsigned long)(x) + (unsigned long)mem))
+
+static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE)));
+static unsigned int tmp[1024] __attribute__((aligned(PAGE_SIZE)));
+static void *root, *mem, *m;
+static struct lowcore *lc;
+volatile unsigned int *p;
+
+/*
+ * Check if a non-access-list protection exception happened for the given
+ * address, in the primary address space.
+ */
+static bool check_pgm_prot(void *ptr)
+{
+ union teid teid;
+
+ if (lc->pgm_int_code != PGM_INT_CODE_PROTECTION)
+ return false;
+
+ teid.val = lc->trans_exc_id;
+
+ /*
+ * depending on the presence of the ESOP feature, the rest of the
+ * field might or might not be meaningful when the m field is 0.
+ */
+ if (!teid.m)
+ return true;
+ return (!teid.acc_list_prot && !teid.asce_id &&
+ (teid.addr == ((unsigned long)ptr >> PAGE_SHIFT)));
+}
+
+static void test_dat(void)
+{
+ report_prefix_push("edat off");
+ /* disable EDAT */
+ ctl_clear_bit(0, CTL0_EDAT);
+
+ /* Check some basics */
+ p[0] = 42;
+ report(p[0] == 42, "pte, r/w");
+ p[0] = 0;
+
+ /* Write protect the page and try to write, expect a fault */
+ protect_page(m, PAGE_ENTRY_P);
+ expect_pgm_int();
+ p[0] = 42;
+ unprotect_page(m, PAGE_ENTRY_P);
+ report(!p[0] && check_pgm_prot(m), "pte, ro");
+
+ /*
+ * The FC bit (for large pages) should be ignored because EDAT is
+ * off. We set a value and then we try to read it back again after
+ * setting the FC bit. This way we can check if large pages were
+ * erroneously enabled despite EDAT being off.
+ */
+ p[0] = 42;
+ protect_dat_entry(m, SEGMENT_ENTRY_FC, pgtable_level_pmd);
+ report(p[0] == 42, "pmd, fc=1, r/w");
+ unprotect_dat_entry(m, SEGMENT_ENTRY_FC, pgtable_level_pmd);
+ p[0] = 0;
+
+ /*
+ * Segment protection should work even with EDAT off, try to write
+ * anyway and expect a fault
+ */
+ protect_dat_entry(m, SEGMENT_ENTRY_P, pgtable_level_pmd);
+ expect_pgm_int();
+ p[0] = 42;
+ report(!p[0] && check_pgm_prot(m), "pmd, ro");
+ unprotect_dat_entry(m, SEGMENT_ENTRY_P, pgtable_level_pmd);
+
+ /* The FC bit should be ignored because EDAT is off, like above */
+ p[0] = 42;
+ protect_dat_entry(m, REGION3_ENTRY_FC, pgtable_level_pud);
+ report(p[0] == 42, "pud, fc=1, r/w");
+ unprotect_dat_entry(m, REGION3_ENTRY_FC, pgtable_level_pud);
+ p[0] = 0;
+
+ /*
+ * Region1/2/3 protection should not work, because EDAT is off.
+ * Protect the various region1/2/3 entries and write, expect the
+ * write to be successful.
+ */
+ protect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pud);
+ p[0] = 42;
+ report(p[0] == 42, "pud, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pud);
+ p[0] = 0;
+
+ protect_dat_entry(m, REGION_ENTRY_P, pgtable_level_p4d);
+ p[0] = 42;
+ report(p[0] == 42, "p4d, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, pgtable_level_p4d);
+ p[0] = 0;
+
+ protect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pgd);
+ p[0] = 42;
+ report(p[0] == 42, "pgd, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pgd);
+ p[0] = 0;
+
+ report_prefix_pop();
+}
+
+static void test_edat1(void)
+{
+ report_prefix_push("edat1");
+ /* Enable EDAT */
+ ctl_set_bit(0, CTL0_EDAT);
+ p[0] = 0;
+
+ /*
+ * Segment protection should work normally, try to write and expect
+ * a fault.
+ */
+ expect_pgm_int();
+ protect_dat_entry(m, SEGMENT_ENTRY_P, pgtable_level_pmd);
+ p[0] = 42;
+ report(!p[0] && check_pgm_prot(m), "pmd, ro");
+ unprotect_dat_entry(m, SEGMENT_ENTRY_P, pgtable_level_pmd);
+
+ /*
+ * Region1/2/3 protection should work now, because EDAT is on. Try
+ * to write anyway and expect a fault.
+ */
+ expect_pgm_int();
+ protect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pud);
+ p[0] = 42;
+ report(!p[0] && check_pgm_prot(m), "pud, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pud);
+
+ expect_pgm_int();
+ protect_dat_entry(m, REGION_ENTRY_P, pgtable_level_p4d);
+ p[0] = 42;
+ report(!p[0] && check_pgm_prot(m), "p4d, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, pgtable_level_p4d);
+
+ expect_pgm_int();
+ protect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pgd);
+ p[0] = 42;
+ report(!p[0] && check_pgm_prot(m), "pgd, ro");
+ unprotect_dat_entry(m, REGION_ENTRY_P, pgtable_level_pgd);
+
+ /* Large pages should work */
+ p[0] = 42;
+ install_large_page(root, 0, mem);
+ report(p[0] == 42, "pmd, large");
+
+ /*
+ * Prefixing should not work with large pages. Since the lower
+ * addresses are mapped with small pages, which are subject to
+ * prefixing, and the pages mapped with large pages are not subject
+ * to prefixing, this is the resulting scenario:
+ *
+ * virtual 0 = real 0 -> absolute prefix_buf
+ * virtual prefix_buf = real prefix_buf -> absolute 0
+ * VIRT(0) -> absolute 0
+ * VIRT(prefix_buf) -> absolute prefix_buf
+ *
+ * The testcase checks if the memory at virtual 0 has the same
+ * content as the memory at VIRT(prefix_buf) and the memory at
+ * VIRT(0) has the same content as the memory at virtual prefix_buf.
+ * If prefixing is erroneously applied for large pages, the testcase
+ * will therefore fail.
+ */
+ report(!memcmp(0, VIRT(prefix_buf), LC_SIZE) &&
+ !memcmp(prefix_buf, VIRT(0), LC_SIZE),
+ "pmd, large, prefixing");
+
+ report_prefix_pop();
+}
+
+static void test_edat2(void)
+{
+ report_prefix_push("edat2");
+ p[0] = 42;
+
+ /* Huge pages should work */
+ install_huge_page(root, 0, mem);
+ report(p[0] == 42, "pud, huge");
+
+ /* Prefixing should not work with huge pages, just like large pages */
+ report(!memcmp(0, VIRT(prefix_buf), LC_SIZE) &&
+ !memcmp(prefix_buf, VIRT(0), LC_SIZE),
+ "pmd, large, prefixing");
+
+ report_prefix_pop();
+}
+
+static unsigned int setup(void)
+{
+ bool has_edat1 = test_facility(8);
+ bool has_edat2 = test_facility(78);
+ unsigned long pa, va;
+
+ if (has_edat2 && !has_edat1)
+ report_abort("EDAT2 available, but EDAT1 not available");
+
+ /* Setup DAT 1:1 mapping and memory management */
+ setup_vm();
+ root = (void *)(stctg(1) & PAGE_MASK);
+
+ /*
+ * Get a pgd worth of virtual memory, so we can test things later
+ * without interfering with the test code or the interrupt handler
+ */
+ mem = alloc_vpages_aligned(BIT_ULL(PGD_PAGE_SHIFT), PGD_PAGE_SHIFT);
+ assert(mem);
+ va = (unsigned long)mem;
+
+ /* Map the first 1GB of real memory */
+ for (pa = 0; pa < SZ_1G; pa += PAGE_SIZE, va += PAGE_SIZE)
+ install_page(root, pa, (void *)va);
+
+ /*
+ * Move the lowcore to a known non-zero location. This is needed
+ * later to check whether prefixing is working with large pages.
+ */
+ assert((unsigned long)&prefix_buf < SZ_2G);
+ memcpy(prefix_buf, 0, LC_SIZE);
+ set_prefix((uint32_t)(uintptr_t)prefix_buf);
+ /* Clear the old copy */
+ memset(prefix_buf, 0, LC_SIZE);
+
+ /* m will point to tmp through the new virtual mapping */
+ m = VIRT(&tmp);
+ /* p is the same as m but volatile */
+ p = (volatile unsigned int *)m;
+
+ return has_edat1 + has_edat2;
+}
+
+int main(void)
+{
+ unsigned int edat;
+
+ report_prefix_push("edat");
+ edat = setup();
+
+ test_dat();
+
+ if (edat)
+ test_edat1();
+ else
+ report_skip("EDAT not available");
+
+ if (edat >= 2)
+ test_edat2();
+ else
+ report_skip("EDAT2 not available");
+
+ report_prefix_pop();
+ return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 9f81a608..a0ec8864 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -103,3 +103,6 @@ file = sie.elf
[mvpg]
file = mvpg.elf
timeout = 10
+
+[edat]
+file = edat.elf
--
2.31.1