[kvm-unit-tests PATCH v5] s390x: uv-host: Add access checks for donated memory

[Janosch Frank <frankja@linux.ibm.com>]

Let's check if the UV really protected all the memory we donated.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
---
This patch is clearly cursed :)
---
 s390x/uv-host.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/s390x/uv-host.c b/s390x/uv-host.c
index dfcebe10..191e8b3f 100644
--- a/s390x/uv-host.c
+++ b/s390x/uv-host.c
@@ -45,6 +45,32 @@ static void cpu_loop(void)
 	for (;;) {}
 }
 
+/*
+ * Checks if a memory area is protected as secure memory.
+ * Will return true if all pages are protected, false otherwise.
+ */
+static bool access_check_3d(uint8_t *access_ptr, uint64_t len)
+{
+	assert(!(len & ~PAGE_MASK));
+	assert(!((uint64_t)access_ptr & ~PAGE_MASK));
+
+	while (len) {
+		expect_pgm_int();
+		READ_ONCE(*access_ptr);
+		if (clear_pgm_int() != PGM_INT_CODE_SECURE_STOR_ACCESS)
+			return false;
+		expect_pgm_int();
+		WRITE_ONCE(*access_ptr, 42);
+		if (clear_pgm_int() != PGM_INT_CODE_SECURE_STOR_ACCESS)
+			return false;
+
+		access_ptr += PAGE_SIZE;
+		len -= PAGE_SIZE;
+	}
+
+	return true;
+}
+
 static struct cmd_list cmds[] = {
 	{ "init", UVC_CMD_INIT_UV, sizeof(struct uv_cb_init), BIT_UVC_CMD_INIT_UV },
 	{ "create conf", UVC_CMD_CREATE_SEC_CONF, sizeof(struct uv_cb_cgc), BIT_UVC_CMD_CREATE_SEC_CONF },
@@ -332,6 +358,10 @@ static void test_cpu_create(void)
 	report(rc == 0 && uvcb_csc.header.rc == UVC_RC_EXECUTED &&
 	       uvcb_csc.cpu_handle, "success");
 
+	rc = access_check_3d((uint8_t *)uvcb_csc.stor_origin,
+			     uvcb_qui.cpu_stor_len);
+	report(rc, "Storage protection");
+
 	tmp = uvcb_csc.stor_origin;
 	uvcb_csc.stor_origin = (unsigned long)memalign(PAGE_SIZE, uvcb_qui.cpu_stor_len);
 	rc = uv_call(0, (uint64_t)&uvcb_csc);
@@ -430,6 +460,13 @@ static void test_config_create(void)
 	rc = uv_call(0, (uint64_t)&uvcb_cgc);
 	report(rc == 0 && uvcb_cgc.header.rc == UVC_RC_EXECUTED, "successful");
 
+	rc = access_check_3d((uint8_t *)uvcb_cgc.conf_base_stor_origin,
+			     uvcb_qui.conf_base_phys_stor_len);
+	report(rc, "Base storage protection");
+
+	rc = access_check_3d((uint8_t *)uvcb_cgc.conf_var_stor_origin, vsize);
+	report(rc, "Variable storage protection");
+
 	uvcb_cgc.header.rc = 0;
 	uvcb_cgc.header.rrc = 0;
 	tmp = uvcb_cgc.guest_handle;
-- 
2.34.1