Isn't by default PIT and PIC are initialized in Kernel? Is something more needed on top of it? I have enable PIC interuupt using following code :- > PIC Programming > ;; PIC > mov al, #0x00 > out 0x21, AL ;master pic: all IRQs unmasked > out 0xA1, AL ;slave pic: all IRQs unmasked Also, I wonder if LAPIC need to be configured and initialized properly. I don't want to use LAPIC, can it be disabled in KVM. I am just using one VCPU. -Thanks Abhishek -----Original Message----- From: Avi Kivity [mailto:avi@xxxxxxxxxx] Sent: Thursday, August 20, 2009 1:29 AM To: Saksena, Abhishek Cc: kvm@xxxxxxxxxxxxxxx Subject: Re: KVM's PIT and PIC programming question On 08/20/2009 12:26 AM, Saksena, Abhishek wrote: > Hi Guys, > I am writing very simple bios for KVM (not using Qemu but creating a simple io device models around KVM). I am having trouble in receiving regular Timer interrupts after programming PIT. > > I think I have enabled PIC and PIT correctly using following code:- > > PIC Programming > ;; PIC > mov al, #0x00 > out 0x21, AL ;master pic: all IRQs unmasked > out 0xA1, AL ;slave pic: all IRQs unmasked > > > PIT Programming > > and also enable PIT to genrate regular timer interruput > > SET_INT_VECTOR(0x08, #0xF000, #int08_handler) > mov al, #0x34 ; timer0: binary count, 16bit count, mode 2 > out 0x43, al > mov al, #0x00 ; maximum count of 0000H = 18.2Hz > out 0x40, al > out 0x40, al > > > PIT Timer ISR code > > Timer ISR code > > ;--------- > ;- INT08 - > ;--------- > .org 0xfea5 ; INT 08h System Timer ISR Entry Point > int08_handler: > sti > push ax > push ds > mov ax, #0x0040 > mov ds, ax > mov ax, 0x006c ; increment lower word > inc ax > mov 0x006c, ax > jnz inc_done > mov ax, 0x006e ; increment upper word > inc ax > mov 0x006e, ax > > > > For some reason I never see int08_handler ever been called. Any clues what may be wrong? I am creating only one VCPU > > > Things to check: - have you initialized the kernel PIC and PIT? - are interrupts enabled? -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
