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qemu/hw/ppc
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Nicholas Piggin 5eadeeec0d hw/ppc: Avoid decrementer rounding errors 
The decrementer register contains a relative time in timebase units.
When writing to DECR this is converted and stored as an absolute value
in nanosecond units, reading DECR converts back to relative timebase.

The tb<->ns conversion of the relative part can cause rounding such that
a value writen to the decrementer can read back a different, with time
held constant. This is a particular problem for a deterministic icount
and record-replay trace.

Fix this by storing the absolute value in timebase units rather than
nanoseconds. The math before:
  store:  decr_next = now_ns + decr * ns_per_sec / tb_per_sec
  load:        decr = (decr_next - now_ns) * tb_per_sec / ns_per_sec
  load(store): decr = decr * ns_per_sec / tb_per_sec * tb_per_sec /
                      ns_per_sec

After:
  store:  decr_next = now_ns * tb_per_sec / ns_per_sec + decr
  load:        decr = decr_next - now_ns * tb_per_sec / ns_per_sec
  load(store): decr = decr

Fixes: 9fddaa0c0c ("PowerPC merge: real time TB and decrementer - faster and simpler exception handling (Jocelyn Mayer)")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
(cherry picked from commit 8e0a5ac878)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-09-25 23:43:49 +03:00
..
e500-ccsr.h Use OBJECT_DECLARE_SIMPLE_TYPE when possible 2020-09-18 14:12:32 -04:00
e500.c hw/ppc/e500: fix broken snapshot replay 2023-09-11 10:53:50 +03:00
e500.h hw/ppc/e500: Remove if statement which is now always true 2022-10-17 16:15:09 -03:00
e500plat.c hw/ppc/e500: Remove if statement which is now always true 2022-10-17 16:15:09 -03:00
fdt.c target/ppc: Split page size information into a separate allocation 2018-04-27 18:05:22 +10:00
fw_cfg.c hw/ppc: Implement fw_cfg_arch_key_name() 2019-05-23 14:10:31 +02:00
Kconfig MIPS patches queue 2022-10-31 06:36:15 -04:00
mac_newworld.c mac_newworld: Turn CORE99_VIA_CONFIG defines into an enum 2022-10-31 18:48:23 +00:00
mac_oldworld.c mac_{old|new}world: Code style fix adding missing braces to if-s 2022-10-31 18:48:23 +00:00
meson.build ppc440_uc.c: Move DDR2 SDRAM controller model to ppc4xx_sdram.c 2022-10-28 13:15:22 -03:00
mpc8544_guts.c ppc/ppc4xx: Convert printfs() 2022-01-04 07:55:34 +01:00
mpc8544ds.c hw/ppc/e500: Remove if statement which is now always true 2022-10-17 16:15:09 -03:00
pef.c ppc/pef.c: initialize cgs->ready in kvmppc_svm_init() 2021-06-03 18:10:31 +10:00
pegasos2.c hw/isa/vt82c686: Create rtc-time alias in boards instead 2022-10-31 11:32:07 +01:00
pnv_bmc.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
pnv_core.c target/ppc: introduce ppc_maybe_interrupt 2022-10-28 13:15:22 -03:00
pnv_homer.c ppc/pnv: Add a HOMER model to POWER10 2022-03-02 06:51:39 +01:00
pnv_lpc.c pnv_lpc: disable reentrancy detection for lpc-hc 2023-09-11 10:53:50 +03:00
pnv_occ.c ppc/pnv: Remove PnvOCC::psi link 2022-04-20 18:00:30 -03:00
pnv_pnor.c block: Change blk_{pread,pwrite}() param order 2022-07-12 12:14:56 +02:00
pnv_psi.c ppc/pnv: Remove useless checks in set_irq handlers 2022-04-20 18:00:30 -03:00
pnv_sbe.c ppc/pnv: Add initial P9/10 SBE model 2022-08-31 14:08:05 -03:00
pnv_xscom.c ppc/pnv: Add initial P9/10 SBE model 2022-08-31 14:08:05 -03:00
pnv.c reset: allow registering handlers that aren't called by snapshot loading 2022-10-27 11:34:31 +01:00
ppc4xx_devs.c ppc4xx_sdram: Move ppc4xx_sdram_banks() to ppc4xx_sdram.c 2022-10-28 13:15:23 -03:00
ppc4xx_pci.c ppc4xx: Fix code style problems reported by checkpatch 2022-08-31 17:05:15 -03:00
ppc4xx_sdram.c ppc4xx_sdram: Add errp parameter to ppc4xx_sdram_banks() 2022-10-28 13:15:23 -03:00
ppc405_boards.c ppc4xx_sdram: Rename functions to prevent name clashes 2022-10-17 16:15:09 -03:00
ppc405_uc.c ppc4xx_sdram: QOM'ify 2022-10-17 16:15:09 -03:00
ppc405.h ppc4xx_sdram: QOM'ify 2022-10-17 16:15:09 -03:00
ppc440_bamboo.c hw/ppc: set machine->fdt in bamboo_load_device_tree() 2022-10-17 16:15:10 -03:00
ppc440_pcix.c Do not include exec/address-spaces.h if it's not really necessary 2021-05-02 17:24:51 +02:00
ppc440_uc.c ppc440_uc.c: Move DDR2 SDRAM controller model to ppc4xx_sdram.c 2022-10-28 13:15:22 -03:00
ppc440.h ppc440_sdram: QOM'ify 2022-10-17 16:15:09 -03:00
ppc_booke.c Use g_new() & friends where that makes obvious sense 2022-03-21 15:44:44 +01:00
ppc.c hw/ppc: Avoid decrementer rounding errors 2023-09-25 23:43:49 +03:00
ppce500_spin.c powerpc tcg: Fix Lesser GPL version number 2020-11-15 16:38:50 +01:00
prep_systemio.c ppc/6xx: Allocate IRQ lines with qdev_init_gpio_in() 2022-07-18 13:59:43 -03:00
prep.c hw/ppc/prep: Fix wiring of PIC -> CPU interrupt 2023-05-31 09:43:56 +03:00
rs6000_mc.c Do not include hw/boards.h if it's not really necessary 2021-05-02 17:24:51 +02:00
sam460ex.c hw/ppc: set machine->fdt in sam460ex_load_device_tree() 2022-10-17 16:15:10 -03:00
spapr_caps.c Trivial: 3 char repeat typos 2022-06-28 11:06:02 +02:00
spapr_cpu_core.c hw/ppc: free env->tb_env in spapr_unrealize_vcpu() 2022-04-04 08:49:06 +02:00
spapr_drc.c hw/ppc/spapr_drc.c: use g_autofree in spapr_drc_by_index() 2022-03-02 06:51:40 +01:00
spapr_events.c Use g_new() & friends where that makes obvious sense 2022-03-21 15:44:44 +01:00
spapr_hcall.c target/ppc: introduce ppc_maybe_interrupt 2022-10-28 13:15:22 -03:00
spapr_iommu.c spapr/ddw: Reset DMA when the last non-default window is removed 2022-07-06 10:22:37 -03:00
spapr_irq.c spapr/xics: Drop unused argument to xics_kvm_has_broken_disconnect() 2020-12-14 15:50:55 +11:00
spapr_numa.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
spapr_nvdimm.c hw/ppc: check if spapr_drc_index() returns NULL in spapr_nvdimm.c 2022-07-28 10:31:54 -03:00
spapr_ovec.c spapr: Improve handling of memory unplug with old guests 2021-01-19 10:20:29 +11:00
spapr_pci_nvlink2.c hw/ppc/pnv: Avoid dynamic stack allocation 2022-09-22 16:38:28 +01:00
spapr_pci_vfio.c pci: Export pci_for_each_device_under_bus*() 2021-11-01 19:36:11 -04:00
spapr_pci.c hw/ppc/spapr_pci.c: Use device_cold_reset() rather than device_legacy_reset() 2022-10-17 16:15:10 -03:00
spapr_rng.c Do not include cpu.h if it's not really necessary 2021-05-02 17:24:51 +02:00
spapr_rtas_ddw.c spapr/ddw: Implement 64bit query extension 2022-07-06 10:22:37 -03:00
spapr_rtas.c target/ppc: introduce ppc_maybe_interrupt 2022-10-28 13:15:22 -03:00
spapr_rtc.c rtc: Have event RTC_CHANGE identify the RTC by QOM path 2022-02-28 11:39:35 +01:00
spapr_softmmu.c osdep: Move memalign-related functions to their own header 2022-03-07 13:16:49 +00:00
spapr_tpm_proxy.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
spapr_vio.c hw/ppc/spapr_vio.c: use g_autofree in spapr_dt_vdevice() 2022-03-02 06:51:40 +01:00
spapr_vof.c Remove qemu-common.h include from most units 2022-04-06 14:31:55 +02:00
spapr.c reset: allow registering handlers that aren't called by snapshot loading 2022-10-27 11:34:31 +01:00
trace-events ppc4xx_sdram: Generalise bank setup 2022-10-28 13:15:23 -03:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
virtex_ml507.c hw/ppc: set machine->fdt in xilinx_load_device_tree() 2022-10-17 16:15:10 -03:00
vof.c ppc/vof: Fix missed fields in VOF cleanup 2023-09-11 10:53:50 +03:00