On 12/01/15 06:35, winddy wrote: > Dear Expert, > I see in file OvmfPkg\Sec\SecMain.c, line 810: > // > // Initialize Local APIC Timer hardware and disable Local APIC Timer > // interrupts before initializing the Debug Agent and the debug timer is > // enabled. > // > InitializeApicTimer (0, MAX_UINT32, TRUE, 5); > DisableApicTimerInterrupt (); > > Ovmf initializes apic timer and give it a vector number 5, according to > "Intel® 64 and IA-32 Architectures Software Developer’s Manual", vol 3, > 10.5.2 Valid Interrupt Vectors: > > > When an interrupt vector in the range of 0 to 15 is sent or received through > the local APIC, the APIC indicates an > illegal vector in its Error Status Register (see Section 10.5.3, “Error > Handling”). The Intel 64 and IA-32 architec- > tures reserve vectors 16 through 31 for predefined interrupts, exceptions, > and Intel-reserved encodings (see Table > 6-1). However, the local APIC does not treat vectors in this range as > illegal. When an illegal vector value (0 to 15) > is written to an LVT entry and the delivery mode is Fixed (bits 8-11 equal > 0), the APIC may signal an illegal vector > error, without regard to whether the mask bit is set or whether an interrupt > is actually seen on the input. > > > > So here "vector 5" is a fake value, right?
Yes. Please see point (5) in: http://thread.gmane.org/gmane.comp.bios.edk2.devel/3019/focus=3168 > we just want to let timer be running, and we can fill it with 6, 7, 8, also? > If next function "DisableApicTimerInterrupt()" does not invoke, a interrupt > will be occurred when current timer value > down to Zero? Yes, there is a very small window between the two lines you quoted when the timer is ticking / armed. See point (4) in the message linked above. Thanks Laszlo > > > And I see CPU Interrupt 5 is "BOUND Range Exceeded Exception" for BOUND > instruction. > > > Thanks. > > > > > > ------------------ > BR > winddy_zhang > _______________________________________________ > edk2-devel mailing list > [email protected] > https://lists.01.org/mailman/listinfo/edk2-devel > _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
