[kvm-unit-tests PATCH v2 4/8] s390x: uv-host: Add access exception test

[Janosch Frank <frankja@xxxxxxxxxxxxx>]

Let's check that we get access exceptions if the UVCB is on an invalid
page or starts at a valid page and crosses into an invalid one.

Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Reviewed-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
Reviewed-by: Nico Boehr <nrb@xxxxxxxxxxxxx>
---
 s390x/uv-host.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/s390x/uv-host.c b/s390x/uv-host.c
index 0762e690..a626a651 100644
--- a/s390x/uv-host.c
+++ b/s390x/uv-host.c
@@ -15,12 +15,14 @@
 #include <sclp.h>
 #include <smp.h>
 #include <uv.h>
+#include <mmu.h>
 #include <asm/page.h>
 #include <asm/sigp.h>
 #include <asm/pgtable.h>
 #include <asm/asm-offsets.h>
 #include <asm/interrupt.h>
 #include <asm/facility.h>
+#include <asm/pgtable.h>
 #include <asm/uv.h>
 #include <asm-generic/barrier.h>
 
@@ -142,6 +144,54 @@ static void test_uv_uninitialized(void)
 	report_prefix_pop();
 }
 
+static void test_access(void)
+{
+	struct uv_cb_header *uvcb;
+	void *pages =  alloc_pages(1);
+	uint16_t pgm;
+	int i;
+
+	/* Put UVCB on second page which we will protect later */
+	uvcb = pages + PAGE_SIZE;
+
+	report_prefix_push("access");
+
+	report_prefix_push("non-crossing");
+	protect_page(uvcb, PAGE_ENTRY_I);
+	for (i = 0; cmds[i].name; i++) {
+		expect_pgm_int();
+		mb();
+		uv_call_once(0, (uint64_t)uvcb);
+		pgm = clear_pgm_int();
+		report(pgm == PGM_INT_CODE_PAGE_TRANSLATION, "%s", cmds[i].name);
+	}
+	report_prefix_pop();
+
+	report_prefix_push("crossing");
+	/*
+	 * Put the header into the readable page 1, everything after
+	 * the header will be on the second, invalid page.
+	 */
+	uvcb -= 1;
+	for (i = 0; cmds[i].name; i++) {
+		uvcb->cmd = cmds[i].cmd;
+		uvcb->len = cmds[i].len;
+
+		expect_pgm_int();
+		mb();
+		uv_call_once(0, (uint64_t)uvcb);
+		pgm = clear_pgm_int();
+		report(pgm == PGM_INT_CODE_PAGE_TRANSLATION, "%s", cmds[i].name);
+	}
+	report_prefix_pop();
+
+	uvcb += 1;
+	unprotect_page(uvcb, PAGE_ENTRY_I);
+
+	free_pages(pages);
+	report_prefix_pop();
+}
+
 static void test_config_destroy(void)
 {
 	int rc;
@@ -607,6 +657,8 @@ int main(void)
 	test_init();
 
 	setup_vmem();
+	test_access();
+
 	test_config_create();
 	test_cpu_create();
 	test_cpu_destroy();
-- 
2.34.1