On 22.11.21 12:29, Marc Hartmayer wrote:
> In the past s390 used a fixed command line length of 896 bytes. This has
> changed
> with the Linux commit 5ecb2da660ab ("s390: support command lines longer than
> 896
> bytes"). There is now a parm area indicating the maximum command line size.
> This
> parm area has always been initialized to zero, so with older kernels this
> field
> would read zero and we must then assume that only 896 bytes are available.
>
> Acked-by: Viktor Mihajlovski <mihaj...@de.ibm.com>
> Signed-off-by: Marc Hartmayer <mhart...@linux.ibm.com>
> ---
> hw/s390x/ipl.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
> index 7ddca0127fc2..092c66b3f9f1 100644
> --- a/hw/s390x/ipl.c
> +++ b/hw/s390x/ipl.c
> @@ -37,8 +37,9 @@
>
> #define KERN_IMAGE_START 0x010000UL
> #define LINUX_MAGIC_ADDR 0x010008UL
> +#define KERN_PARM_AREA_SIZE_ADDR 0x010430UL
> #define KERN_PARM_AREA 0x010480UL
> -#define KERN_PARM_AREA_SIZE 0x000380UL
> +#define LEGACY_KERN_PARM_AREA_SIZE 0x000380UL
> #define INITRD_START 0x800000UL
> #define INITRD_PARM_START 0x010408UL
> #define PARMFILE_START 0x001000UL
> @@ -110,6 +111,21 @@ static uint64_t bios_translate_addr(void *opaque,
> uint64_t srcaddr)
> return srcaddr + dstaddr;
> }
>
> +static uint64_t get_max_kernel_cmdline_size(void)
> +{
> + uint64_t *size_ptr = rom_ptr(KERN_PARM_AREA_SIZE_ADDR,
> sizeof(*size_ptr));
> +
> + if (size_ptr) {
> + uint64_t size;
> +
> + size = be64_to_cpu(*size_ptr);
> + if (size != 0) {
Could do "if (size) {"
> + return size;
> + }
> + }
> + return LEGACY_KERN_PARM_AREA_SIZE;
> +}
> +
> static void s390_ipl_realize(DeviceState *dev, Error **errp)
> {
> MachineState *ms = MACHINE(qdev_get_machine());
> @@ -197,10 +213,11 @@ static void s390_ipl_realize(DeviceState *dev, Error
> **errp)
> ipl->start_addr = KERN_IMAGE_START;
> /* Overwrite parameters in the kernel image, which are "rom" */
> if (parm_area) {
> - if (cmdline_size > KERN_PARM_AREA_SIZE) {
> + uint64_t max_cmdline_size = get_max_kernel_cmdline_size();
We might want an empty line here.
> + if (cmdline_size > max_cmdline_size) {
> error_setg(errp,
> "kernel command line exceeds maximum size:
> %zu > %lu",
> - cmdline_size, KERN_PARM_AREA_SIZE);
> + cmdline_size, max_cmdline_size);
> return;
> }
>
>
Reviewed-by: David Hildenbrand <da...@redhat.com>
--
Thanks,
David / dhildenb
