[kvm-unit-tests PATCH v7 29/35] common/sieve: Support machines without MMU

[Nicholas Piggin <npiggin@gmail.com>]

Not all powerpc CPUs provide MMU support. Define vm_available() that is
true by default but archs can override it. Use this to run VM tests.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Huth <thuth@redhat.com>
Cc: kvm@vger.kernel.org
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 common/sieve.c      | 14 ++++++++------
 lib/ppc64/asm/mmu.h |  1 -
 lib/ppc64/mmu.c     |  2 +-
 lib/vmalloc.c       |  7 +++++++
 lib/vmalloc.h       |  2 ++
 5 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/common/sieve.c b/common/sieve.c
index 8fe05ef13..db084691a 100644
--- a/common/sieve.c
+++ b/common/sieve.c
@@ -40,12 +40,14 @@ int main(void)
 
     printf("starting sieve\n");
     test_sieve("static", static_data, STATIC_SIZE);
-    setup_vm();
-    test_sieve("mapped", static_data, STATIC_SIZE);
-    for (i = 0; i < 3; ++i) {
-	v = malloc(VSIZE);
-	test_sieve("virtual", v, VSIZE);
-	free(v);
+    if (vm_available()) {
+	    setup_vm();
+	    test_sieve("mapped", static_data, STATIC_SIZE);
+	    for (i = 0; i < 3; ++i) {
+		v = malloc(VSIZE);
+		test_sieve("virtual", v, VSIZE);
+		free(v);
+	    }
     }
 
     return 0;
diff --git a/lib/ppc64/asm/mmu.h b/lib/ppc64/asm/mmu.h
index fadeee4bc..eaff0f1f7 100644
--- a/lib/ppc64/asm/mmu.h
+++ b/lib/ppc64/asm/mmu.h
@@ -3,7 +3,6 @@
 
 #include <asm/pgtable.h>
 
-bool vm_available(void);
 bool mmu_enabled(void);
 void mmu_enable(pgd_t *pgtable);
 void mmu_disable(void);
diff --git a/lib/ppc64/mmu.c b/lib/ppc64/mmu.c
index 7e445fdaf..ac9c0a285 100644
--- a/lib/ppc64/mmu.c
+++ b/lib/ppc64/mmu.c
@@ -23,7 +23,7 @@
 
 static pgd_t *identity_pgd;
 
-bool vm_available(void)
+bool vm_available(void) /* weak override */
 {
 	return cpu_has_radix;
 }
diff --git a/lib/vmalloc.c b/lib/vmalloc.c
index 572682576..cf2ef7a70 100644
--- a/lib/vmalloc.c
+++ b/lib/vmalloc.c
@@ -206,10 +206,17 @@ void init_alloc_vpage(void *top)
 	spin_unlock(&lock);
 }
 
+bool __attribute__((__weak__)) vm_available(void)
+{
+	return true;
+}
+
 void __setup_vm(void *opaque)
 {
 	phys_addr_t base, top;
 
+	assert_msg(vm_available(), "Virtual memory not available. Must check vm_available() before calling setup_vm()");
+
 	if (alloc_ops == &vmalloc_ops)
 		return;
 
diff --git a/lib/vmalloc.h b/lib/vmalloc.h
index 0269fdde9..e81be39f4 100644
--- a/lib/vmalloc.h
+++ b/lib/vmalloc.h
@@ -17,6 +17,8 @@ extern void setup_vm(void);
 /* As above, plus passes an opaque value to setup_mmu(). */
 extern void __setup_vm(void *opaque);
 
+/* common/ tests must check availability before calling setup_vm() */
+extern bool vm_available(void);
 /* Set up paging */
 extern void *setup_mmu(phys_addr_t top, void *opaque);
 /* Walk the page table and resolve the virtual address to a physical address */
-- 
2.42.0