Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20190903' into staging

target-arm queue:
 * Revert and correctly fix refactoring of unallocated_encoding()
 * Take exceptions on ATS instructions when needed
 * aspeed/timer: Provide back-pressure information for short periods
 * memory: Remove unused memory_region_iommu_replay_all()
 * hw/arm/smmuv3: Log a guest error when decoding an invalid STE
 * hw/arm/smmuv3: Remove spurious error messages on IOVA invalidations
 * target/arm: Fix SMMLS argument order
 * hw/arm: Use ARM_CPU_TYPE_NAME() macro when appropriate
 * hw/arm: Correct reference counting for creation of various objects
 * includes: remove stale [smp|max]_cpus externs
 * tcg/README: fix typo
 * atomic_template: fix indentation in GEN_ATOMIC_HELPER
 * include/exec/cpu-defs.h: fix typo
 * target/arm: Free TCG temps in trans_VMOV_64_sp()
 * target/arm: Don't abort on M-profile exception return in linux-user mode

# gpg: Signature made Tue 03 Sep 2019 16:35:19 BST
# gpg:                using RSA key E1A5C593CD419DE28E8315CF3C2525ED14360CDE
# gpg:                issuer "peter.maydell@linaro.org"
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>" [ultimate]
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>" [ultimate]
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>" [ultimate]
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20190903: (21 commits)
  target/arm: Don't abort on M-profile exception return in linux-user mode
  target/arm: Free TCG temps in trans_VMOV_64_sp()
  include/exec/cpu-defs.h: fix typo
  atomic_template: fix indentation in GEN_ATOMIC_HELPER
  tcg/README: fix typo s/afterwise/afterwards/
  includes: remove stale [smp|max]_cpus externs
  hw/net/xilinx_axi: Use object_initialize_child for correct ref. counting
  hw/dma/xilinx_axi: Use object_initialize_child for correct ref. counting
  hw/arm/fsl-imx: Add the cpu as child of the SoC object
  hw/arm: Use sysbus_init_child_obj for correct reference counting
  hw/arm: Use object_initialize_child for correct reference counting
  hw/arm: Use ARM_CPU_TYPE_NAME() macro when appropriate
  target/arm: Fix SMMLS argument order
  hw/arm/smmuv3: Remove spurious error messages on IOVA invalidations
  hw/arm/smmuv3: Log a guest error when decoding an invalid STE
  memory: Remove unused memory_region_iommu_replay_all()
  aspeed/timer: Provide back-pressure information for short periods
  target/arm: Take exceptions on ATS instructions when needed
  target/arm: Allow ARMCPRegInfo read/write functions to throw exceptions
  target/arm: Factor out unallocated_encoding for aarch32
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/hw/timer/aspeed_timer.c b/hw/timer/aspeed_timer.c
index ed81d5c..59c2bbe 100644
--- a/hw/timer/aspeed_timer.c
+++ b/hw/timer/aspeed_timer.c
@@ -44,6 +44,13 @@ enum timer_ctrl_op {
     op_pulse_enable
 };
 
+/*
+ * Minimum value of the reload register to filter out short period
+ * timers which have a noticeable impact in emulation. 5us should be
+ * enough, use 20us for "safety".
+ */
+#define TIMER_MIN_NS (20 * SCALE_US)
+
 /**
  * Avoid mutual references between AspeedTimerCtrlState and AspeedTimer
  * structs, as it's a waste of memory. The ptimer BH callback needs to know
@@ -98,6 +105,14 @@ static inline uint32_t calculate_ticks(struct AspeedTimer *t, uint64_t now_ns)
     return t->reload - MIN(t->reload, ticks);
 }
 
+static uint32_t calculate_min_ticks(AspeedTimer *t, uint32_t value)
+{
+    uint32_t rate = calculate_rate(t);
+    uint32_t min_ticks = muldiv64(TIMER_MIN_NS, rate, NANOSECONDS_PER_SECOND);
+
+    return  value < min_ticks ? min_ticks : value;
+}
+
 static inline uint64_t calculate_time(struct AspeedTimer *t, uint32_t ticks)
 {
     uint64_t delta_ns;
@@ -261,7 +276,7 @@ static void aspeed_timer_set_value(AspeedTimerCtrlState *s, int timer, int reg,
     switch (reg) {
     case TIMER_REG_RELOAD:
         old_reload = t->reload;
-        t->reload = value;
+        t->reload = calculate_min_ticks(t, value);
 
         /* If the reload value was not previously set, or zero, and
          * the current value is valid, try to start the timer if it is