On 05/02/2014 11:57 PM, Ulrich Obergfell wrote: > The current implementation of the 'kvm_pio' tracepoint in emulator_pio_in_out() > only tells us that 'something' has been read from or written to an I/O port. To > improve the usability of the tracepoint, I propose to include the value/content > that has been read or written in the trace output. The proposed patch aims at > the more common case where a single 8-bit or 16-bit or 32-bit value has been > read or written -- it does not fully cover the case where 'count' is greater > than one. > > This is an example of what the patch can do (trace of PCI config space access). > > - on the host > > # trace-cmd record -e kvm:kvm_pio -f "(port >= 0xcf8) && (port <= 0xcff)" > /sys/kernel/debug/tracing/events/kvm/kvm_pio/filter > Hit Ctrl^C to stop recording > > - in a Linux guest > > # dd if=/sys/bus/pci/devices/0000:00:06.0/config bs=2 count=4 | hexdump > 4+0 records in > 4+0 records out > 8 bytes (8 B) copied, 0.000114056 s, 70.1 kB/s > 0000000 1af4 1001 0507 0010 > 0000008 > > - on the host > > # trace-cmd report > ... > qemu-kvm-23216 [001] 15211.994089: kvm_pio: pio_write > at 0xcf8 size 4 count 1 val 0x80003000 > qemu-kvm-23216 [001] 15211.994108: kvm_pio: pio_read > at 0xcfc size 2 count 1 val 0x1af4 > qemu-kvm-23216 [001] 15211.994129: kvm_pio: pio_write > at 0xcf8 size 4 count 1 val 0x80003000 > qemu-kvm-23216 [001] 15211.994136: kvm_pio: pio_read > at 0xcfe size 2 count 1 val 0x1001 > qemu-kvm-23216 [001] 15211.994143: kvm_pio: pio_write > at 0xcf8 size 4 count 1 val 0x80003004 > qemu-kvm-23216 [001] 15211.994150: kvm_pio: pio_read > at 0xcfc size 2 count 1 val 0x507 > qemu-kvm-23216 [001] 15211.994155: kvm_pio: pio_write > at 0xcf8 size 4 count 1 val 0x80003004 > qemu-kvm-23216 [001] 15211.994161: kvm_pio: pio_read > at 0xcfe size 2 count 1 val 0x10 > Nice. Could please check "perf kvm stat" to see if "--event=ioport" can work after your patch? Reviewed-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> -- 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
