|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 06/10] hvm/hpet: comparator can only change when master clock is enabled.
On 04/15/14 03:05, Jan Beulich wrote: On 14.04.14 at 21:50, <dslutz@xxxxxxxxxxx> wrote:On 04/14/14 11:07, Jan Beulich wrote:As to the change - I'm not sure: The quoted description from the specification cal also be read to mean that interrupt generation is optional, but comparator increment will always happen. As long as this can't be clarified, I'd prefer to stay with the code as is.I think the code needs to change to match the spec. #define timer_enabled(h, n) (timer_config(h, n) & HPET_TN_ENABLE) vs #define hpet_enabled(h) (h->hpet.config & HPET_CFG_ENABLE) The change uses hpet_enabled() (I.E. Overall Enable).Correct. But do we really need this? When the HPET is globally disabled, hpet_read_maincounter() returns a fixed value, and hence - due to the comparators not changing either - hpet_get_comparator() will too even without the addition. So if at all, the change would be mostly for documentation purposes. We do need this. hpet_get_comparator() does not return a fixed value. Without this change it will always adjust to hpet_read_maincounter(). Here is an example using the manual test code: dcs-xen-54:~/xen/tools/tests/vhpet>gdb --args ./test_vhpet 0 3 0 1 0x13 GNU gdb (GDB) 7.6.2.20140108-cvs Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-unknown-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... Reading symbols from /home/don/xen/tools/tests/vhpet/test_vhpet...done. (gdb) b hpet.c:128 Breakpoint 1 at 0x400ac1: file hpet.c, line 128. (gdb) r Starting program: /home/don/xen/tools/tests/vhpet/./test_vhpet 0 3 0 1 0x13 warning: no loadable sections found in added symbol-file system-supplied DSO at 0x7ffff7ffd000 test_vhpet 1.0 hvm_clock_cost=0 hpet_mult=3 hpet_add=0 tick_count=1 debug=0x13 skip_load=1 HPET: capability 0xf424008086a201 config 0() isr 0 counter 0(0) timer0 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer0 period 0(0) fsb 0 timer1 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer1 period 0(0) fsb 0 timer2 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer2 period 0(0) fsb 0 HPET: capability 0xf424008086a201 config 0() isr 0 counter 0(0) timer0 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer0 period 0(0) fsb 0 timer1 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer1 period 0(0) fsb 0 timer2 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer2 period 0(0) fsb 0 skip_load HPET: capability 0xf424008086a201 config 0() isr 0 counter 0(0) timer0 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer0 period 0(0) fsb 0 timer1 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer1 period 0(0) fsb 0 timer2 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer2 period 0(0) fsb 0 mc64=0x108a8(67,752) mc_offset=0x10898(67,736) hvm_guest_time=0x10(16) HPET: capability 0xf424008086a201 config 0() isr 0 counter 0x108a8(67,752) timer0 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer0 period 0(0) fsb 0 timer1 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer1 period 0(0) fsb 0 timer2 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer2 period 0(0) fsb 0 HPET: capability 0xf424008086a201 config 0() isr 0 counter 0x108a8(67,752) timer0 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer0 period 0(0) fsb 0 timer1 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer1 period 0(0) fsb 0 timer2 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer2 period 0(0) fsb 0 skip_load HPET: capability 0xf424008086a201 config 0() isr 0 counter 0x108a8(67,752) timer0 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer0 period 0(0) fsb 0 timer1 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer1 period 0(0) fsb 0 timer2 config 0xf0000000000030() cmp 0xffffffffffffffff(-1) timer2 period 0(0) fsb 0 Breakpoint 1, hpet_read64 (h=0x604d68 <dom1+8>, addr=264) at hpet.c:128 128 return hpet_get_comparator(h, HPET_TN(CMP, addr), guest_time_hpet(h)); (gdb) c Continuing. hpet_writel: HPET_TN_SETVAL cmp=0x3e514(255,252) timer=0 Breakpoint 1, hpet_read64 (h=0x604d68 <dom1+8>, addr=264) at hpet.c:128 128 return hpet_get_comparator(h, HPET_TN(CMP, addr), guest_time_hpet(h)); (gdb) c Continuing. hpet_writel: period=0xf424(62,500) timer=0 Breakpoint 1, hpet_read64 (h=0x604d68 <dom1+8>, addr=264) at hpet.c:128 128 return hpet_get_comparator(h, HPET_TN(CMP, addr), guest_time_hpet(h)); (gdb) b hpet_get_comparator Breakpoint 2 at 0x400839: file hpet.c, line 87. (gdb) c Continuing. Breakpoint 2, hpet_get_comparator (h=0x604d68 <dom1+8>, tn=0, guest_time=1) at hpet.c:87 87 comparator = h->hpet.comparator64[tn]; (gdb) n 88 if ( timer_is_periodic(h, tn) ) (gdb) 91 uint64_t period = h->hpet.period[tn]; (gdb) 92 if (period) (gdb) 94 elapsed = hpet_read_maincounter(h, guest_time) + (gdb) 95 period - 1 - comparator; (gdb) 94 elapsed = hpet_read_maincounter(h, guest_time) + (gdb) 96 comparator += (elapsed / period) * period; (gdb) p comparator $1 = 255252 (gdb) p/x comparator $2 = 0x3e514 (gdb) p elapsed $3 = 18446744073709426615 (gdb) p/x elapsed $4 = 0xfffffffffffe17b7 (gdb) p elapsed / period $5 = 295147905179350 (gdb) p/x elapsed / period $6 = 0x10c6f7a0b5ed6 (gdb) p 295147905179350 * period $7 = 18446744073709375000 (gdb) p/x 295147905179350 * period $8 = 0xfffffffffffd4e18 (gdb) n 97 h->hpet.comparator64[tn] = comparator; (gdb) p comparator $9 = 78636 (gdb) p/x comparator $10 = 0x1332c (gdb) -Don Slutz Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |