On 02/16/2018 11:07 PM, Collin L. Walling wrote:
> It is possible while waiting for multiple types of external
> interrupts that we might have pending irqs remaining between
> irq consumption and irq-type disabling. Those interrupts
> could potentially propagate to the guest after IPL completes
> and cause unwanted behavior.
>
> As it is today, the SCLP will only recognize write events that
> are enabled by the control program's send and receive masks. To
> limit the window for, and prevent further irqs from, ASCII
> console events (specifically keystrokes), we should only enable
> the control program's receive mask when we need it.
>
> As an additional measure, once we've disabled/cleared the control
> program's receive mask, we will print an empty string in order
> to consume any pending service interrupt.
>
> Signed-off-by: Collin L. Walling <wall...@linux.vnet.ibm.com>
This should work some comments below:
> ---
> pc-bios/s390-ccw/menu.c | 5 +++++
> pc-bios/s390-ccw/s390-ccw.h | 1 +
> pc-bios/s390-ccw/sclp.c | 10 ++++------
> 3 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/pc-bios/s390-ccw/menu.c b/pc-bios/s390-ccw/menu.c
> index 9601043..14410a8 100644
> --- a/pc-bios/s390-ccw/menu.c
> +++ b/pc-bios/s390-ccw/menu.c
> @@ -11,6 +11,7 @@
>
> #include "menu.h"
> #include "s390-ccw.h"
> +#include "sclp.h"
>
> #define KEYCODE_NO_INP '\0'
> #define KEYCODE_ESCAPE '\033'
> @@ -117,8 +118,12 @@ static int get_index(void)
>
> memset(buf, 0, sizeof(buf));
>
> + sclp_set_write_mask(SCLP_EVENT_MASK_MSG_ASCII,
> SCLP_EVENT_MASK_MSG_ASCII);
> len = read_prompt(buf, sizeof(buf));
>
> + sclp_set_write_mask(0, SCLP_EVENT_MASK_MSG_ASCII);
> + sclp_print(""); /* Clear any pending service int */
> +
Why cant you use consume_sclp_int from start.S and not do any printing?
Shouldnt sclp_set_write_mask always make an interrupt pending?
> /* If no input, boot default */
> if (len == 0) {
> return 0;
> diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
> index a7e6253..ebdcf86 100644
> --- a/pc-bios/s390-ccw/s390-ccw.h
> +++ b/pc-bios/s390-ccw/s390-ccw.h
> @@ -69,6 +69,7 @@ unsigned int get_loadparm_index(void);
>
> /* sclp.c */
> void sclp_print(const char *string);
> +void sclp_set_write_mask(uint32_t receive_mask, uint32_t send_mask);
> void sclp_setup(void);
> void sclp_get_loadparm_ascii(char *loadparm);
> int sclp_read(char *str, size_t count);
> diff --git a/pc-bios/s390-ccw/sclp.c b/pc-bios/s390-ccw/sclp.c
> index a2f25eb..3836cb4 100644
> --- a/pc-bios/s390-ccw/sclp.c
> +++ b/pc-bios/s390-ccw/sclp.c
> @@ -46,23 +46,21 @@ static int sclp_service_call(unsigned int command, void
> *sccb)
> return 0;
> }
>
> -static void sclp_set_write_mask(void)
> +void sclp_set_write_mask(uint32_t receive_mask, uint32_t send_mask)
> {
> WriteEventMask *sccb = (void *)_sccb;
>
> sccb->h.length = sizeof(WriteEventMask);
> sccb->mask_length = sizeof(unsigned int);
> - sccb->receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
> - sccb->cp_receive_mask = SCLP_EVENT_MASK_MSG_ASCII;
> - sccb->send_mask = SCLP_EVENT_MASK_MSG_ASCII;
> - sccb->cp_send_mask = SCLP_EVENT_MASK_MSG_ASCII;
> + sccb->cp_receive_mask = receive_mask;
> + sccb->cp_send_mask = send_mask;
Isnt this also fixing another issue. write event mask only takes the
control program (the guest) values and the sclp mask are being returned.
>
> sclp_service_call(SCLP_CMD_WRITE_EVENT_MASK, sccb);
> }
>
> void sclp_setup(void)
> {
> - sclp_set_write_mask();
> + sclp_set_write_mask(0, SCLP_EVENT_MASK_MSG_ASCII);
> }
>
> long write(int fd, const void *str, size_t len)
>
