On Mon, 25 Jul 2022 13:08:59 +0000
Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
> Let's check if the UV really protected all the memory we donated.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> s390x/uv-host.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/s390x/uv-host.c b/s390x/uv-host.c
> index dfcebe10..ba6c9008 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(uint64_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 / sizeof(access_ptr);
this looks ugly, although in principle the correct way to handle a
pointer. In this specific case it's techically wrong though (you
actually want sizeof(*access_ptr) )
what about making access_ptr a char*?
then you can do just
access_ptr += PAGE_SIZE;
and you can keep the READ_ONCE and WRITE_ONCE as they are
> + 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((uint64_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((uint64_t *)uvcb_cgc.conf_var_stor_origin, vsize);
> + report(rc, "Base storage protection");
> +
> + rc = access_check_3d((uint64_t *)uvcb_cgc.conf_base_stor_origin,
> + uvcb_qui.conf_base_phys_stor_len);
> + report(rc, "Variable storage protection");
> +
> uvcb_cgc.header.rc = 0;
> uvcb_cgc.header.rrc = 0;
> tmp = uvcb_cgc.guest_handle;
