This patchset implements the ARMv8.1-PMU and ARMv8.4-PMU architecture
extensions. These are fairly small changes on top of the basic
PMUv3 we already implement, and in fact we already had most of
the v8.1-PMU functionality implemented but unadvertised.

In the course of doing this, I found that our naming and use of
isar_feature ID register test functions was slightly inconsistent,
so the first few patches straighten this out and align on an
_aa32_/_aa64_/_any_ convention for which ID registers to test.

The ARMv8.1-PMU extension requires:
 * the evtCount field in PMETYPER<n>_EL0 is 16 bits, not 10
 * MDCR_EL2.HPMD allows event counting to be disabled at EL2
 * two new required events, STALL_FRONTEND and STALL_BACKEND
 * ID register bits in ID_AA64DFR0_EL1 and ID_DFR0
We already implement all of that except the new events;
for QEMU our CPU never "stalls" in that sense, so we can
just implement them as always-reads-zero.

The ARMv8.4-PMU extension adds:
 * one new required event, STALL (again, reads-as-zero)
 * one new system register PMMIR_EL1, which provides information
   about the PMU implementation. Since the only currently defined
   field in it relates to an event we don't provide, we can
   validly implement the register as RAZ.

Two patches fix some bugs I discovered while running this through
Eric's recent kvm-unit-tests PMU tests:
 * we had the wrong definition of the PMCR.DP bit position
 * we incorrectly implemented PMCR.LC as RAZ/WI

I also fix some random minor bugs I noticed while cleaning up the
ID register handling.

Finally there's an implementation of ACTLR2 and HACTLR2 sysregs;
these are pretty trivial but required from Armv8.2 onward. This is
strictly speaking unrelated to perf, but the patch depends on all
the preceding cleanup stuff.

I don't generally use the perf emulation, so testing would be
welcome from people who do.

Changes v1->v2:
 * now rebased on master, so patch 1 fixes up an extra new use of
 * patch 2 is new: take_aarch32_exception should check aa32_pan, not aa64_pan
 * minor fixups per review comments (mostly using 64-bit versions
   of extract/deposit where appropriate)
 * added code to get values of ID registers from KVM
 * when I added that code I ran into a bunch of problems which
   stemmed from our using the 32-bit DBGDIDR as the source of truth
   about numbers of breakpoints etc, which then breaks if the host
   KVM CPU is AArch64-only, so some patches clean that up
 * patch 18 fixes a cut-n-paste error I noticed where we were reading
   entirely the wrong register in aa32_pan and aa32_ats1e1
 * patch 19 adds an isar_feature test to replace an opencoded examination
   of an ID register field
 * patch 20 uses FIELD_EX32 for 32-bit ID registers rather than FIELD_EX64
 * patch 21 implements ACTLR2 and HACTLR2

Patches 1, 3-9, and 13-17 have already been reviewed;
2, 10-12, and 18-21 are new in v2.

-- PMM

Peter Maydell (21):
  target/arm: Add _aa32_ to isar_feature functions testing 32-bit ID
  target/arm: Check aa32_pan in take_aarch32_exception(), not aa64_pan
  target/arm: Add isar_feature_any_fp16 and document naming/usage
  target/arm: Define and use any_predinv isar_feature test
  target/arm: Factor out PMU register definitions
  target/arm: Add and use FIELD definitions for ID_AA64DFR0_EL1
  target/arm: Use FIELD macros for clearing ID_DFR0 PERFMON field
  target/arm: Define an aa32_pmu_8_1 isar feature test function
  target/arm: Add _aa64_ and _any_ versions of pmu_8_1 isar checks
  target/arm: Stop assuming DBGDIDR always exists
  target/arm: Move DBGDIDR into ARMISARegisters
  target/arm: Read debug-related ID registers from KVM
  target/arm: Implement ARMv8.1-PMU extension
  target/arm: Implement ARMv8.4-PMU extension
  target/arm: Provide ARMv8.4-PMU in '-cpu max'
  target/arm: Correct definition of PMCRDP
  target/arm: Correct handling of PMCR_EL0.LC bit
  target/arm: Test correct register in aa32_pan and aa32_ats1e1 checks
  target/arm: Use isar_feature function for testing AA32HPD feature
  target/arm: Use FIELD_EX32 for testing 32-bit fields
  target/arm: Correctly implement ACTLR2, HACTLR2

 target/arm/cpu.h          | 143 +++++++++++++++---
 target/arm/internals.h    |  44 +++++-
 hw/intc/armv7m_nvic.c     |  10 +-
 linux-user/elfload.c      |   4 +-
 target/arm/cpu.c          | 150 +++++++++---------
 target/arm/cpu64.c        |  58 ++++---
 target/arm/debug_helper.c |   6 +-
 target/arm/helper.c       | 311 ++++++++++++++++++++++----------------
 target/arm/kvm32.c        |  25 +++
 target/arm/kvm64.c        |  46 ++++++
 target/arm/translate.c    |   6 +-
 target/arm/vfp_helper.c   |   2 +-
 12 files changed, 544 insertions(+), 261 deletions(-)


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