Re: [Qemu-devel] [PATCH] target-s390x: Mask the SIGP order_code to 8bit.

[Alexander Graf]

On 24.04.17 00:32, Aurelien Jarno wrote:
> From: Philipp Kern <address@hidden>
>
> According to "CPU Signaling and Response", "Signal-Processor Orders",
> the order field is bit position 56-63. Without this, the Linux
> guest kernel is sometimes unable to stop emulation and enters
> an infinite loop of "XXX unknown sigp: 0xffffffff00000005".
>
> Signed-off-by: Philipp Kern <address@hidden>
> Signed-off-by: Aurelien Jarno <address@hidden>
> ---
>  target/s390x/misc_helper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> This patch has been sent by Philipp Kern a lot of time ago, and it seems
> has been lost. I am resending it, as it is still useful.
>
> diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
> index 3bf09ea222..4946b56ab3 100644
> --- a/target/s390x/misc_helper.c
> +++ b/target/s390x/misc_helper.c
> @@ -534,7 +534,7 @@ uint32_t HELPER(sigp)(CPUS390XState *env, uint64_t 
> order_code, uint32_t r1,
>      /* Remember: Use "R1 or R1 + 1, whichever is the odd-numbered register"
>         as parameter (input). Status (output) is always R1. */
>
> -    switch (order_code) {
> +    switch (order_code & 0xff) {

This definitely needs a comment above the mask. Ideally I'd love to just 
change the function prototype to pass order_code as uint8_t, but I don't 
think that's possible with the TCG glue.


Alex