On 4/25/22 18:17, Janis Schoetterl-Glausch wrote:
Some instructions are emulated by KVM. Test that KVM correctly emulates
storage key checking for two of those instructions (STORE CPU ADDRESS,
SET PREFIX).
Test success and error conditions, including coverage of storage and
fetch protection override.
Also add test for TEST PROTECTION, even if that instruction will not be
emulated by KVM under normal conditions.
Signed-off-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>
---
[...]
lib/s390x/asm/arch_def.h | 20 ++--
s390x/skey.c | 227 +++++++++++++++++++++++++++++++++++++++
2 files changed, 238 insertions(+), 9 deletions(-)
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index bab3c374..676a2753 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -55,15 +55,17 @@ struct psw {
#define PSW_MASK_BA 0x0000000080000000UL
#define PSW_MASK_64 (PSW_MASK_BA | PSW_MASK_EA)
-#define CTL0_LOW_ADDR_PROT (63 - 35)
-#define CTL0_EDAT (63 - 40)
-#define CTL0_IEP (63 - 43)
-#define CTL0_AFP (63 - 45)
-#define CTL0_VECTOR (63 - 46)
-#define CTL0_EMERGENCY_SIGNAL (63 - 49)
-#define CTL0_EXTERNAL_CALL (63 - 50)
-#define CTL0_CLOCK_COMPARATOR (63 - 52)
-#define CTL0_SERVICE_SIGNAL (63 - 54)
+#define CTL0_LOW_ADDR_PROT (63 - 35)
+#define CTL0_EDAT (63 - 40)
+#define CTL0_FETCH_PROTECTION_OVERRIDE (63 - 38)
+#define CTL0_STORAGE_PROTECTION_OVERRIDE (63 - 39)
+#define CTL0_IEP (63 - 43)
+#define CTL0_AFP (63 - 45)
+#define CTL0_VECTOR (63 - 46)
+#define CTL0_EMERGENCY_SIGNAL (63 - 49)
+#define CTL0_EXTERNAL_CALL (63 - 50)
+#define CTL0_CLOCK_COMPARATOR (63 - 52)
+#define CTL0_SERVICE_SIGNAL (63 - 54)
#define CR0_EXTM_MASK 0x0000000000006200UL /* Combined external masks */
#define CTL2_GUARDED_STORAGE (63 - 59)
diff --git a/s390x/skey.c b/s390x/skey.c
index edad53e9..39429960 100644
--- a/s390x/skey.c
+++ b/s390x/skey.c
@@ -10,6 +10,7 @@
#include <libcflat.h>
#include <asm/asm-offsets.h>
#include <asm/interrupt.h>
+#include <vmalloc.h>
#include <asm/page.h>
#include <asm/facility.h>
#include <asm/mem.h>
@@ -118,6 +119,227 @@ static void test_invalid_address(void)
report_prefix_pop();
}
+static void test_test_protection(void)
+{
+ unsigned long addr = (unsigned long)pagebuf;
+
+ report_prefix_push("TPROT");
+
+ set_storage_key(pagebuf, 0x10, 0);
+ report(tprot(addr, 0) == 0, "access key 0 -> no protection");
+ report(tprot(addr, 1) == 0, "access key matches -> no protection");
+ report(tprot(addr, 2) == 1, "access key mismatches, no fetch protection -> store protection");
I'd love to see these numerical constants replaced with named constants
in the future so I don't have to look up the tprot CCs every time :)
+
+ set_storage_key(pagebuf, 0x18, 0);
+ report(tprot(addr, 2) == 2, "access key mismatches, fetch protection -> fetch & store protection");
+
+ ctl_set_bit(0, CTL0_STORAGE_PROTECTION_OVERRIDE);
+ set_storage_key(pagebuf, 0x90, 0);
+ report(tprot(addr, 2) == 0, "access key mismatches, storage protection override -> no protection");
+ ctl_clear_bit(0, CTL0_STORAGE_PROTECTION_OVERRIDE);
+
+ set_storage_key(pagebuf, 0x00, 0);
+ report_prefix_pop();
+}
[...]
+/*
+ * Perform SET PREFIX (SPX) instruction while temporarily executing
+ * with access key 1.
+ */
+static void set_prefix_key_1(uint32_t *prefix_ptr)
+{
+ asm volatile (
+ "spka 0x10\n\t"
+ "spx %0\n\t"
+ "spka 0\n"
+ :: "Q" (*prefix_ptr)
+ );
+}
+
+/*
+ * We remapped page 0, making the lowcore inaccessible, which breaks the normal
+ * handler and breaks skipping the faulting instruction.
+ * Just disable dynamic address translation to make things work.
+ */
+static void dat_fixup_pgm_int(void)
+{
+ uint64_t psw_mask = extract_psw_mask();
+
+ psw_mask &= ~PSW_MASK_DAT;
+ load_psw_mask(psw_mask);
+}
+
+#define PREFIX_AREA_SIZE (PAGE_SIZE * 2)
+static char lowcore_tmp[PREFIX_AREA_SIZE] __attribute__((aligned(PREFIX_AREA_SIZE)));
+
Please add a comment that we're testing the fetch access of the operand
since the prefix is only checked for addressing.
+static void test_set_prefix(void)
+{
+ uint32_t *prefix_ptr = (uint32_t *)pagebuf;
+ uint32_t *no_override_prefix_ptr;
+ uint32_t old_prefix;
+ pgd_t *root;
+
+ report_prefix_push("SET PREFIX");
+ root = (pgd_t *)(stctg(1) & PAGE_MASK);
+ old_prefix = get_prefix();
+ memcpy(lowcore_tmp, 0, sizeof(lowcore_tmp));
+ assert(((uint64_t)&lowcore_tmp >> 31) == 0);
+ *prefix_ptr = (uint32_t)(uint64_t)&lowcore_tmp;
+
+ report_prefix_push("zero key");
+ set_prefix(old_prefix);
+ set_storage_key(prefix_ptr, 0x20, 0);
+ set_prefix(*prefix_ptr);
+ report(get_prefix() == *prefix_ptr, "set prefix");
+ report_prefix_pop();
+
+ report_prefix_push("matching key");
+ set_prefix(old_prefix);
+ set_storage_key(pagebuf, 0x10, 0);
+ set_prefix_key_1(prefix_ptr);
+ report(get_prefix() == *prefix_ptr, "set prefix");
+ report_prefix_pop();
+
+ report_prefix_push("mismatching key");
+
+ report_prefix_push("no fetch protection");
+ set_prefix(old_prefix);
+ set_storage_key(pagebuf, 0x20, 0);
+ set_prefix_key_1(prefix_ptr);
+ report(get_prefix() == *prefix_ptr, "set prefix");
+ report_prefix_pop();
+
+ report_prefix_push("fetch protection");
+ set_prefix(old_prefix);
+ set_storage_key(pagebuf, 0x28, 0);
+ expect_pgm_int();
+ set_prefix_key_1(prefix_ptr);
+ check_pgm_int_code(PGM_INT_CODE_PROTECTION);
+ report(get_prefix() == old_prefix, "did not set prefix");
+ report_prefix_pop();
+
+ register_pgm_cleanup_func(dat_fixup_pgm_int);
+
+ report_prefix_push("remapped page, fetch protection");
+ set_prefix(old_prefix);
+ set_storage_key(pagebuf, 0x28, 0);
+ expect_pgm_int();
+ install_page(root, virt_to_pte_phys(root, pagebuf), 0);
+ set_prefix_key_1((uint32_t *)0);
+ install_page(root, 0, 0);
+ check_pgm_int_code(PGM_INT_CODE_PROTECTION);
+ report(get_prefix() == old_prefix, "did not set prefix");
+ report_prefix_pop();
+
+ ctl_set_bit(0, CTL0_FETCH_PROTECTION_OVERRIDE);
+
+ report_prefix_push("fetch protection override applies");
+ set_prefix(old_prefix);
+ set_storage_key(pagebuf, 0x28, 0);
+ install_page(root, virt_to_pte_phys(root, pagebuf), 0);
+ set_prefix_key_1((uint32_t *)0);
+ install_page(root, 0, 0);
+ report(get_prefix() == *prefix_ptr, "set prefix");
+ report_prefix_pop();
+
+ no_override_prefix_ptr = (uint32_t *)(pagebuf + 2048);
+ WRITE_ONCE(*no_override_prefix_ptr, (uint32_t)(uint64_t)&lowcore_tmp);
+ report_prefix_push("fetch protection override does not apply");
+ set_prefix(old_prefix);
+ set_storage_key(pagebuf, 0x28, 0);
+ expect_pgm_int();
+ install_page(root, virt_to_pte_phys(root, pagebuf), 0);
+ set_prefix_key_1((uint32_t *)2048);
+ install_page(root, 0, 0);
+ check_pgm_int_code(PGM_INT_CODE_PROTECTION);
+ report(get_prefix() == old_prefix, "did not set prefix");
+ report_prefix_pop();
+
+ ctl_clear_bit(0, CTL0_FETCH_PROTECTION_OVERRIDE);
+ register_pgm_cleanup_func(NULL);
+ report_prefix_pop();
+ set_storage_key(pagebuf, 0x00, 0);
+ report_prefix_pop();
+}
+
int main(void)
{
report_prefix_push("skey");
@@ -130,6 +352,11 @@ int main(void)
test_set();
test_set_mb();
test_chg();
+ test_test_protection();
+ test_store_cpu_address();
+
+ setup_vm();
+ test_set_prefix();
done:
report_prefix_pop();
return report_summary();
base-commit: 6a7a83ed106211fc0ee530a3a05f171f6a4c4e66
