| Message ID | 1519241752-28083-12-git-send-email-walling@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 21.02.2018 20:35, 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. > > While we're at it, remove assignment of the (non control program) > send and receive masks, as those are actually set by the SCLP. > > Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com> > --- > 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(-) Reviewed-by: Thomas Huth <thuth@redhat.com>
diff --git a/pc-bios/s390-ccw/menu.c b/pc-bios/s390-ccw/menu.c index 01b120d..4f84bfe 100644 --- a/pc-bios/s390-ccw/menu.c +++ b/pc-bios/s390-ccw/menu.c @@ -11,6 +11,7 @@ #include "libc.h" #include "s390-ccw.h" +#include "sclp.h" #define KEYCODE_NO_INP '\0' #define KEYCODE_ESCAPE '\033' @@ -116,8 +117,12 @@ 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) - 1); + sclp_set_write_mask(0, SCLP_EVENT_MASK_MSG_ASCII); + /* 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 f7c12bf..56b0c2a 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; 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)
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. While we're at it, remove assignment of the (non control program) send and receive masks, as those are actually set by the SCLP. Signed-off-by: Collin L. Walling <walling@linux.vnet.ibm.com> --- 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(-)