|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v4 00/42] [RISC-V] virtual interrupt controller (vAPLIC/vIMSIC) support
Hi all,
This series adds the initial virtual interrupt controller (vINTC) support
for RISC-V guests in Xen, based on the Advanced Interrupt Architecture
(AIA): a virtual APLIC (vAPLIC) in MSI mode backed by a virtual IMSIC
(vIMSIC) using hardware guest interrupt files.
Rather than emulating APLIC in direct-delivery mode (which requires
trap-and-emulate for every interrupt and is costly), the series targets
IMSIC from the start. AIA lets a hart implement several "guest interrupt
files" (up to GEILEN), so external interrupts can be delivered to a vCPU
directly by hardware via the VGEIN field of hstatus, without a hypervisor
round-trip. Xen only has to emulate the APLIC MMIO programming interface
and route the guest's intent onto the physical MSI topology; interrupt
delivery itself stays in hardware. Interrupts of devices emulated by Xen
itself (virtual sources) are supported as well: vAPLIC keeps their state
and Xen injects their MSIs into the vCPU's guest interrupt file.
The work breaks down into a few logical blocks:
Self-contained preparatory patches (patches 1-6)
- A helper to test for APLIC MSI mode.
- Make csr_write64() take the CSR name without the CSR_ prefix
(MISRA C Rule 20.12), and add csr_volatile_read64() as its
counterpart, used for CSR_TIME so that get_cycles() no longer
truncates the time counter on RV32.
- Define the IPRIO field of the APLIC target register, and build the
physical APLIC's target hart index with aplic_hart_index(), dropping
the last in-tree duplicate of the AIA hart index formula.
- CPU_NONE as an explicit "no pCPU" marker instead of NR_CPUS.
None of these depends on the rest of the series, so they can go in
ahead of it.
MMIO emulation and vAPLIC (patches 7-10)
- A per-domain MMIO handler table modelled on Arm's framework, so
emulated devices self-register their GPA ranges and the fault path
stays agnostic via a single try_handle_mmio() entry point.
- Tell h/w vINTC sources (a physical IRQ is routed to them) from
virtual ones (driven by a device emulator in Xen) with a new
hw_irqs bitmap.
- vAPLIC MMIO read/write emulation for the h/w sources of the domain.
Writes are limited to the sources the domain owns, and target[]
writes are translated from virtual to physical hart/guest-file
indices. Only MSI delivery mode is emulated, and delegation
(sourcecfg.D) is not supported.
- Leave the h/w source of an IRQ routed to a guest Inactive, as the
guest configures it itself.
vCPU context switching (patches 11-13)
- context_switch() and the helpers it needs: save/restore of H/VS CSRs,
the virtual timer and P2M context, and __context_switch() in assembly.
The VMID is claimed in p2m_ctxt_switch_to() rather than at the next
guest entry.
- Save and restore the AIA CSRs a guest can change (vsiselect and
hviprio{1,2}), gated by hstateen0 where Smstateen is implemented.
- vintc_ctxt_switch_{from,to}() wrappers over new ctxt_switch_{from,to}
hooks in struct vintc_ops, called from the context switch path.
Trap and instruction emulation infrastructure (patches 14-22)
- Extend the exception-table format with type/data fields and add
EX_TYPE_TRAP_INFO so fixups can capture sepc/scause/stval.
- A guest page-fault handler, and trap_redirect() to forward a
synchronous trap back into the guest's VS-mode handler for the faults
which can never become an emulated access.
- Resolve the faulting guest physical address from htval and stval,
which first needs Shtvala to be detected.
- read_guest() (HLV/HLVX) to read guest memory and instructions
safely, the decoding helpers shared by both access types, and the load
and store emulation which dispatches the access through
try_handle_mmio().
vCPU bring-up (patches 23-29)
- Program hstatus.VSXL explicitly, as decoding a trapped instruction
depends on the effective XLEN of the guest.
- continue_new_vcpu(): switch to the idle vCPU's own stack for the idle
vCPU, and enter the guest through the new return_to_new_vcpu() path in
entry.S for a guest one.
- Per-pCPU VGEIN (guest interrupt file) allocator: a bitmap of the files
a hart implements (up to GEILEN) with helpers to assign and release
one, and an owners[] map so a file reported pending in HGEIP can be
traced back to the vCPU it belongs to.
- Stage-2 map a vCPU's physical guest interrupt file to the fixed
per-vCPU GPA page the guest expects, and vaplic_reconfigure_target()
to retarget the domain's h/w sources at a new file.
- imsic_vsfile_attach(), called once the pCPU a vCPU will run on is
known: it assigns a VGEIN, clears and maps the guest interrupt file
and records the IMSIC state as a consistent unit.
- Watch a descheduled vCPU's guest interrupt file through HGEIE, so that
a guest blocked on an external interrupt is woken up instead of
waiting for an unrelated event to schedule it again.
vCPU migration between pCPUs (patches 30-35)
- An APLIC-IMSIC-hart sync barrier, using an interrupt identity
reserved for Xen.
- The move of a vCPU's IMSIC guest interrupt file, following the
sequence the AIA spec prescribes: take, zero and G-stage map the new
file, retarget the domain's APLIC interrupts at it and fence off
straggler MSIs with the barrier, save and clear the old file (in a
single IPI to the pCPU owning it), then restore that state into the
new file and update the vCPU's hstatus.VGEIN.
- The move is done by the vCPU itself on its way back to the guest,
from check_for_pcpu_work() through a new vintc_ops.enter_guest hook,
rather than from arch_move_irqs() (see "Changes in v4" below).
Virtual interrupt sources (patches 36-42)
- vcpu_imsic_inject() to make an identity pending in a vCPU's guest
interrupt file from any pCPU, through its SETIPNUM_LE register, and
the synchronisation of such injections with a migration of the file.
- Emulate genmsi.
- Keep the guest's view of sourcecfg[], setie[]/clrie[] and
domaincfg.IE, which can now be cleared, for both kinds of source.
- Emulate target[], the pending bits and the MSIs of virtual sources,
and vintc_set_irq_level(), through which a device emulator drives
the line of its virtual source.
CI tests: https://gitlab.com/xen-project/people/olkur/xen/-/pipelines/3063920059
---
Changes in v4:
- Add support for virtual interrupts, i.e. interrupts of devices
emulated by Xen (patches 36-42). Could go separately as we don't really use
now virtual interrupts. It was tested based on Denis M's vuart framework +
some extra patch to make it work for RISC-V.
- Fix a race between the vCPU migration and the vCPU entering the guest
with a stale hstatus.VGEIN: the vCPU's guest interrupt file is now
moved by the vCPU itself right before entering the guest, rather than
from arch_move_irqs(). See "xen/riscv: move a vCPU's guest interrupt
file on its way to the guest" for details.
- Reorder the series: self-contained patches are moved to the beginning
(patches 1-6) to make them easier to merge, and vCPU bring-up now
comes before vCPU migration.
- Drop the patches which are already in staging.
- Address the comments from ML.
- The remaining changes are described in the per-patch changelogs.
---
Changes in v3:
- Address the comments from ML.
- New patches: "drop INSN_{16,32}BIT_MASK and report unknown instruction
lengths", "set the domain type for 64-bit kernel images" and
"introduce CPU_NONE" (used instead of NR_CPUS as "no CPU" marker).
- Drop patch series dependecny as it was merged to upstream/staging.
---
Changes in v2:
- The series has grown from 17 to 39 patches. vCPU context switching, vCPU
migration between pCPUs and the vCPU bring-up path (continue_new_vcpu(),
attaching an IMSIC h/w interrupt file) are now part of it to have better
context of how things are using, together with the trap-side pieces the
MMIO emulation depends on (faulting GPA resolution, Shtvala detection,
instruction decoding).
- vintc_state_{save,restore}() became vintc_ctxt_switch_{from,to}() and
vcpu_aia_init() became imsic_vsfile_attach(); "xen/riscv: manage
IRQ_DISABLED flag in APLIC irq enable/disable callbacks" is no longer part
of this series. The remaining changes are described in the per-patch
changelogs.
---
Oleksii Kurochko (42):
xen/riscv: add helper to check APLIC MSI mode
xen/riscv: address violation of MISRA C Rule 20.12 in csr_write64()
xen/riscv: introduce csr_volatile_read64()
xen/riscv: define the IPRIO field of the APLIC target register
xen/riscv: build the target hart index via aplic_hart_index()
xen/riscv: introduce CPU_NONE
xen/riscv: introduce device-agnostic MMIO emulation dispatch
xen/riscv: distinguish h/w and virtual vINTC sources
xen/riscv: implement virtual APLIC MMIO emulation
xen/riscv: leave the h/w source of an IRQ routed to a guest inactive
xen/riscv: implement vCPU context switching
xen/riscv: save and restore vsiselect on vCPU context switch
xen/riscv: introduce vintc_ctxt_switch_{from,to}()
xen/riscv: extend exception tables with type and data fields
xen/riscv: add guest page fault handling stub
xen/riscv: implement trap redirection to a guest
xen/riscv: detect Shtvala
xen/riscv: resolve the faulting guest physical address
xen/riscv: add guest memory read helper
xen/riscv: add helpers for decoding a trapped load or store
xen/riscv: add guest load emulation for trapped MMIO accesses
xen/riscv: add guest store emulation for trapped MMIO accesses
xen/riscv: set the guest's XLEN explicitly in hstatus.VSXL
xen/riscv: implement continue_new_vcpu()
xen/riscv: add basic VGEIN management for AIA guests
xen/riscv: map IMSIC interrupt file for vCPUs
xen/riscv: introduce vaplic_reconfigure_target()
xen/riscv: introduce IMSIC h/w interrupt file attaching to vcpu
xen/riscv: wake up a descheduled vCPU on a guest external interrupt
xen/riscv: implement APLIC-IMSIC-hart sync barrier for vCPU migration
xen/riscv: introduce imsic_migrate_vcpu()
xen/riscv: remap interrupts to new IMSIC VS-file
xen/riscv: save and clear the old IMSIC VS-file on vCPU migration
xen/riscv: restore register state in the new IMSIC VS-file
xen/riscv: move a vCPU's guest interrupt file on its way to the guest
xen/riscv: send MSIs to a vCPU's guest interrupt file
xen/riscv: sync with IMSIC VS-file injections on vCPU migration
xen/riscv: emulate the vAPLIC genmsi register
xen/riscv: emulate vAPLIC sourcecfg[], setie[] and domaincfg.IE
xen/riscv: emulate target[] of virtual vAPLIC sources
xen/riscv: emulate the pending bits and MSIs of virtual vAPLIC sources
xen/riscv: drive the line of a virtual vAPLIC source
docs/misc/riscv/booting.txt | 11 +
xen/arch/riscv/Makefile | 2 +
xen/arch/riscv/aia.c | 180 +++
xen/arch/riscv/aplic-priv.h | 2 +
xen/arch/riscv/aplic.c | 243 +++-
xen/arch/riscv/cpufeature.c | 1 +
xen/arch/riscv/device.c | 17 +-
xen/arch/riscv/domain-build.c | 8 +
xen/arch/riscv/domain.c | 341 +++++-
xen/arch/riscv/emulate.c | 582 +++++++++
xen/arch/riscv/entry.S | 87 ++
xen/arch/riscv/extable.c | 48 +-
xen/arch/riscv/guestcopy.c | 68 ++
xen/arch/riscv/imsic.c | 900 +++++++++++++-
xen/arch/riscv/include/asm/aia.h | 7 +
xen/arch/riscv/include/asm/aplic.h | 47 +-
xen/arch/riscv/include/asm/config.h | 3 +
xen/arch/riscv/include/asm/cpufeature.h | 1 +
xen/arch/riscv/include/asm/csr.h | 47 +-
xen/arch/riscv/include/asm/current.h | 6 +
xen/arch/riscv/include/asm/domain.h | 22 +-
xen/arch/riscv/include/asm/emulate.h | 10 +
xen/arch/riscv/include/asm/extable.h | 61 +-
xen/arch/riscv/include/asm/gpr-num.h | 53 +
xen/arch/riscv/include/asm/guest_access.h | 28 +
xen/arch/riscv/include/asm/imsic.h | 58 +-
xen/arch/riscv/include/asm/intc.h | 34 +-
xen/arch/riscv/include/asm/irq.h | 5 +-
xen/arch/riscv/include/asm/mmio.h | 48 +
xen/arch/riscv/include/asm/p2m.h | 1 -
xen/arch/riscv/include/asm/processor.h | 14 +-
xen/arch/riscv/include/asm/regs.h | 23 +-
xen/arch/riscv/include/asm/riscv_encoding.h | 28 +-
xen/arch/riscv/include/asm/setup.h | 2 +
xen/arch/riscv/include/asm/smp.h | 2 +-
xen/arch/riscv/include/asm/system.h | 3 +
xen/arch/riscv/include/asm/time.h | 4 +-
xen/arch/riscv/include/asm/traps.h | 9 +
xen/arch/riscv/include/asm/vaplic.h | 66 +
xen/arch/riscv/intc.c | 76 +-
xen/arch/riscv/irq.c | 2 +-
xen/arch/riscv/mmio.c | 205 ++++
xen/arch/riscv/p2m.c | 157 ++-
xen/arch/riscv/riscv64/asm-offsets.c | 19 +-
xen/arch/riscv/setup.c | 2 +
xen/arch/riscv/smp.c | 4 +-
xen/arch/riscv/stubs.c | 5 -
xen/arch/riscv/time.c | 4 +-
xen/arch/riscv/traps.c | 91 +-
xen/arch/riscv/vaplic.c | 1201 ++++++++++++++++++-
50 files changed, 4659 insertions(+), 179 deletions(-)
create mode 100644 xen/arch/riscv/emulate.c
create mode 100644 xen/arch/riscv/include/asm/emulate.h
create mode 100644 xen/arch/riscv/include/asm/gpr-num.h
create mode 100644 xen/arch/riscv/include/asm/mmio.h
create mode 100644 xen/arch/riscv/mmio.c
--
2.56.0
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |