[kvm-unit-tests 1/5] lib: s390x: Add function to get page root

Janosch Frank
2026-04-15T08:52:37Z

It's time to hide the access to cr1 behind a function and add typing
to the tests that used void* instead of pgdt_t*.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
lib/s390x/mmu.h | 7 +++++++
lib/s390x/sie.c | 3 ++-
s390x/diag258.c | 4 ++--
s390x/edat.c | 5 +++--
s390x/mvpg-sie.c | 2 +-
s390x/pv-edat1.c | 4 ++--
s390x/sie-dat.c | 2 +-
s390x/skey.c | 7 +++----
8 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/lib/s390x/mmu.h b/lib/s390x/mmu.h
index dadc2e60..6ba19d28 100644
--- a/lib/s390x/mmu.h
+++ b/lib/s390x/mmu.h
@@ -10,6 +10,8 @@
#ifndef _S390X_MMU_H_
#define _S390X_MMU_H_

+#include <asm/arch_def.h>
+
enum pgt_level {
pgtable_level_pgd = 1,
pgtable_level_p4d,
@@ -95,4 +97,9 @@ static inline void unprotect_page(void *vaddr, unsigned long prot)

void *get_dat_entry(pgd_t *pgtable, void *vaddr, enum pgt_level level);

+static inline pgd_t *get_page_root(void)
+{
+ return (pgd_t *)(stctg(1) & PAGE_MASK);
+}
+
#endif /* _ASMS390X_MMU_H_ */
diff --git a/lib/s390x/sie.c b/lib/s390x/sie.c
index 0fa915cf..a397400b 100644
--- a/lib/s390x/sie.c
+++ b/lib/s390x/sie.c
@@ -17,6 +17,7 @@
#include <alloc_page.h>
#include <vmalloc.h>
#include <sclp.h>
+#include <mmu.h>

void sie_expect_validity(struct vm *vm)
{
@@ -156,7 +157,7 @@ uint8_t *sie_guest_alloc(uint64_t guest_size)
pgd_t *root;

setup_vm();
- root = (pgd_t *)(stctg(1) & PAGE_MASK);
+ root = get_page_root();

/*
* Start of guest memory in host virtual space needs to be aligned to
diff --git a/s390x/diag258.c b/s390x/diag258.c
index 8ba75a72..bbcb92db 100644
--- a/s390x/diag258.c
+++ b/s390x/diag258.c
@@ -82,7 +82,7 @@ static void test_priv(void)

static void *page_map_outside_real_space(phys_addr_t page_real)
{
- pgd_t *root = (pgd_t *)(stctg(1) & PAGE_MASK);
+ pgd_t *root = get_page_root();
void *vaddr = alloc_vpage();

install_page(root, page_real, vaddr);
@@ -109,7 +109,7 @@ static void test_refbk_real(void)
refbk_page = alloc_page();

/* Map refblk page outside of physical memory identity mapping */
- root = (pgd_t *)(stctg(1) & PAGE_MASK);
+ root = get_page_root();
refbk = page_map_outside_real_space(virt_to_pte_phys(root, refbk_page));

/* Assert the mapping really is outside identity mapping */
diff --git a/s390x/edat.c b/s390x/edat.c
index 89b9c2d3..c6a8021a 100644
--- a/s390x/edat.c
+++ b/s390x/edat.c
@@ -21,7 +21,8 @@

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 void *mem, *m;
+static pgd_t *root;
volatile unsigned int *p;

/*
@@ -237,7 +238,7 @@ static unsigned int setup(void)

/* Setup DAT 1:1 mapping and memory management */
setup_vm();
- root = (void *)(stctg(1) & PAGE_MASK);
+ root = get_page_root();

/*
* Get a pgd worth of virtual memory, so we can test things later
diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
index 893de2cf..8666d554 100644
--- a/s390x/mvpg-sie.c
+++ b/s390x/mvpg-sie.c
@@ -89,7 +89,7 @@ static void setup_guest(void)
pgd_t *root;

setup_vm();
- root = (pgd_t *)(stctg(1) & PAGE_MASK);
+ root = get_page_root();

snippet_setup_guest(&vm, false);
snippet_init(&vm, SNIPPET_NAME_START(c, mvpg_snippet),
diff --git a/s390x/pv-edat1.c b/s390x/pv-edat1.c
index 6acfe6c4..43b3bd4c 100644
--- a/s390x/pv-edat1.c
+++ b/s390x/pv-edat1.c
@@ -34,7 +34,7 @@
#define PARAM(n, step) (((unsigned long)(n) << 32) | (step))

static struct vm vm;
-static void *root;
+static pgd_t *root;

extern const char SNIPPET_NAME_START(c, pv_memhog)[];
extern const char SNIPPET_NAME_END(c, pv_memhog)[];
@@ -441,7 +441,7 @@ static void init(void)

setup_vm();

- root = (void *)(stctg(1) & PAGE_MASK);
+ root = get_page_root();
ctl_set_bit(0, CTL0_EDAT);

guest_memory = alloc_pages(GUEST_ORDER - PAGE_SHIFT);
diff --git a/s390x/sie-dat.c b/s390x/sie-dat.c
index 44bf29fe..18b536d1 100644
--- a/s390x/sie-dat.c
+++ b/s390x/sie-dat.c
@@ -69,7 +69,7 @@ static void setup_guest(void)
pgd_t *root;

setup_vm();
- root = (pgd_t *)(stctg(1) & PAGE_MASK);
+ root = get_page_root();

snippet_setup_guest(&vm, false);

diff --git a/s390x/skey.c b/s390x/skey.c
index 7c7a8090..0aa4b6c6 100644
--- a/s390x/skey.c
+++ b/s390x/skey.c
@@ -13,6 +13,7 @@
#include <asm/interrupt.h>
#include <vmalloc.h>
#include <css.h>
+#include <mmu.h>
#include <asm/page.h>
#include <asm/facility.h>
#include <asm/mem.h>
@@ -465,10 +466,9 @@ 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;
+ pgd_t *root = get_page_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);
@@ -583,11 +583,10 @@ static void test_msch(void)
struct schib *schib = (struct schib *)pagebuf;
struct schib *no_override_schib;
int test_device_sid;
- pgd_t *root;
+ pgd_t *root = get_page_root();
int cc;

report_prefix_push("MSCH");
- root = (pgd_t *)(stctg(1) & PAGE_MASK);
test_device_sid = css_enumerate();

if (!(test_device_sid & SCHID_ONE)) {
--
2.51.0