From 133bedc1b844e1c883e202c511d2686a2468fb7f Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Mon, 10 Jan 2011 21:46:37 +0200 Subject: [PATCH] kvm,8250: Fix "too much work for irq4" problems This patch fixes the "too much work for irq4" problems caused by the fact that we never set the UART_IIR_NO_INT flag in the emulation layer. This makes the interrupt handler in the guest kernel process as much as possible which triggers a warning. Signed-off-by: Pekka Enberg --- 8250-serial.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/8250-serial.c b/8250-serial.c index 6056ed6..834c523 100644 --- a/8250-serial.c +++ b/8250-serial.c @@ -23,6 +23,8 @@ struct serial8250_device { uint8_t mcr; uint8_t lsr; uint8_t scr; + + uint8_t counter; }; static struct serial8250_device devices[] = { @@ -37,11 +39,15 @@ static struct serial8250_device devices[] = { [1] = { .iobase = 0x2f8, .irq = 3, + + .iir = UART_IIR_NO_INT, }, /* ttyS2 */ [2] = { .iobase = 0x3e8, .irq = 4, + + .iir = UART_IIR_NO_INT, }, }; @@ -158,6 +164,11 @@ static bool serial8250_out(struct kvm *self, uint16_t port, void *data, int size } fflush(stdout); + if (dev->counter++ > 10) { + dev->iir = UART_IIR_NO_INT; + dev->counter = 0; + } + break; } case UART_IER: @@ -200,6 +211,8 @@ static bool serial8250_in(struct kvm *self, uint16_t port, void *data, int size, switch (offset) { case UART_TX: if (dev->lsr & UART_LSR_DR) { + dev->iir = UART_IIR_NO_INT; + dev->lsr &= ~UART_LSR_DR; ioport__write8(data, dev->thr); }