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authorStefan Hajnoczi <stefanha@redhat.com>2024-12-21 08:13:16 -0500
committerStefan Hajnoczi <stefanha@redhat.com>2024-12-21 08:13:16 -0500
commit60a07d4a6e65f51916a417adb5e56b3f7b38ed22 (patch)
treea656637054bb172bdb07bb51fe3abb66d8efcf8b /docs/specs
parente3a207722b783675b362db4ae22a449f42a26b24 (diff)
parent2fc8f50eadad5dcc99bc5de1333808b9de47a097 (diff)
downloadfocaccia-qemu-60a07d4a6e65f51916a417adb5e56b3f7b38ed22.tar.gz
focaccia-qemu-60a07d4a6e65f51916a417adb5e56b3f7b38ed22.zip
Merge tag 'pull-riscv-to-apply-20241220' of https://github.com/alistair23/qemu into staging
RISC-V PR for 10.0

* Correct the validness check of iova
* Fix APLIC in_clrip and clripnum write emulation
* Support riscv-iommu-sys device
* Add Tenstorrent Ascalon CPU
* Add AIA userspace irqchip_split support
* Add Microblaze V generic board
* Upgrade ACPI SPCR table to support SPCR table revision 4 format
* Remove tswap64() calls from HTIF
* Support 64-bit address of initrd
* Introduce svukte ISA extension
* Support ssstateen extension
* Support for RV64 Xiangshan Nanhu CPU

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* tag 'pull-riscv-to-apply-20241220' of https://github.com/alistair23/qemu: (39 commits)
  target/riscv: add support for RV64 Xiangshan Nanhu CPU
  target/riscv: add ssstateen
  target/riscv/tcg: hide warn for named feats when disabling via priv_ver
  target/riscv: Include missing headers in 'internals.h'
  target/riscv: Include missing headers in 'vector_internals.h'
  target/riscv: Check svukte is not enabled in RV32
  target/riscv: Expose svukte ISA extension
  target/riscv: Check memory access to meet svukte rule
  target/riscv: Support hstatus[HUKTE] bit when svukte extension is enabled
  target/riscv: Support senvcfg[UKTE] bit when svukte extension is enabled
  target/riscv: Add svukte extension capability variable
  hw/riscv: Add the checking if DTB overlaps to kernel or initrd
  hw/riscv: Add a new struct RISCVBootInfo
  hw/riscv: Support to load DTB after 3GB memory on 64-bit system.
  hw/char/riscv_htif: Clarify MemoryRegionOps expect 32-bit accesses
  hw/char/riscv_htif: Explicit little-endian implementation
  MAINTAINERS: Cover RISC-V HTIF interface
  tests/qtest/bios-tables-test: Update virt SPCR golden reference for RISC-V
  hw/acpi: Upgrade ACPI SPCR table to support SPCR table revision 4 format
  qtest: allow SPCR acpi table changes
  ...

Conflicts:
  target/riscv/cpu.c

  Merge conflict with DEFINE_PROP_END_OF_LIST() removal. No Property
  array terminator is needed anymore.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'docs/specs')
-rw-r--r--docs/specs/index.rst1
-rw-r--r--docs/specs/riscv-aia.rst83
-rw-r--r--docs/specs/riscv-iommu.rst30
3 files changed, 111 insertions, 3 deletions
diff --git a/docs/specs/index.rst b/docs/specs/index.rst
index ff5a1f03da..d7675cebc2 100644
--- a/docs/specs/index.rst
+++ b/docs/specs/index.rst
@@ -37,3 +37,4 @@ guest hardware that is specific to QEMU.
    rapl-msr
    rocker
    riscv-iommu
+   riscv-aia
diff --git a/docs/specs/riscv-aia.rst b/docs/specs/riscv-aia.rst
new file mode 100644
index 0000000000..8097e2f897
--- /dev/null
+++ b/docs/specs/riscv-aia.rst
@@ -0,0 +1,83 @@
+.. _riscv-aia:
+
+RISC-V AIA support for RISC-V machines
+======================================
+
+AIA (Advanced Interrupt Architecture) support is implemented in the ``virt``
+RISC-V machine for TCG and KVM accelerators.
+
+The support consists of two main modes:
+
+- "aia=aplic": adds one or more APLIC (Advanced Platform Level Interrupt Controller)
+  devices
+- "aia=aplic-imsic": adds one or more APLIC device and an IMSIC (Incoming MSI
+   Controller) device for each CPU
+
+From an user standpoint, these modes will behave the same regardless of the accelerator
+used.  From a developer standpoint the accelerator settings will change what it being
+emulated in userspace versus what is being emulated by an in-kernel irqchip.
+
+When running TCG, all controllers are emulated in userspace, including machine mode
+(m-mode) APLIC and IMSIC (when applicable).
+
+When running KVM:
+
+- no m-mode is provided, so there is no m-mode APLIC or IMSIC emulation regardless of
+  the AIA mode chosen
+- with "aia=aplic", s-mode APLIC will be emulated by userspace
+- with "aia=aplic-imsic" there are two possibilities.  If no additional KVM option
+  is provided there will be no APLIC or IMSIC emulation in userspace, and the virtual
+  machine will use the provided in-kernel APLIC and IMSIC controllers.  If the user
+  chooses to use the irqchip in split mode via "-accel kvm,kernel-irqchip=split",
+  s-mode APLIC will be emulated while using the s-mode IMSIC from the irqchip
+
+The following table summarizes how the AIA and accelerator options defines what
+we will emulate in userspace:
+
+
+.. list-table:: How AIA and accel options changes controller emulation
+   :widths: 25 25 25 25 25 25 25
+   :header-rows: 1
+
+   * - Accel
+     - Accel props
+     - AIA type
+     - APLIC m-mode
+     - IMSIC m-mode
+     - APLIC s-mode
+     - IMSIC s-mode
+   * - tcg
+     - ---
+     - aplic
+     - emul
+     - n/a
+     - emul
+     - n/a
+   * - tcg
+     - ---
+     - aplic-imsic
+     - emul
+     - emul
+     - emul
+     - emul
+   * - kvm
+     - ---
+     - aplic
+     - n/a
+     - n/a
+     - emul
+     - n/a
+   * - kvm
+     - none
+     - aplic-imsic
+     - n/a
+     - n/a
+     - in-kernel
+     - in-kernel
+   * - kvm
+     - irqchip=split
+     - aplic-imsic
+     - n/a
+     - n/a
+     - emul
+     - in-kernel
diff --git a/docs/specs/riscv-iommu.rst b/docs/specs/riscv-iommu.rst
index 463f4cffb6..b1538c9ead 100644
--- a/docs/specs/riscv-iommu.rst
+++ b/docs/specs/riscv-iommu.rst
@@ -6,9 +6,9 @@ RISC-V IOMMU support for RISC-V machines
 QEMU implements a RISC-V IOMMU emulation based on the RISC-V IOMMU spec
 version 1.0 `iommu1.0`_.
 
-The emulation includes a PCI reference device, riscv-iommu-pci, that QEMU
-RISC-V boards can use.  The 'virt' RISC-V machine is compatible with this
-device.
+The emulation includes a PCI reference device (riscv-iommu-pci) and a platform
+bus device (riscv-iommu-sys) that QEMU RISC-V boards can use.  The 'virt'
+RISC-V machine is compatible with both devices.
 
 riscv-iommu-pci reference device
 --------------------------------
@@ -83,6 +83,30 @@ Several options are available to control the capabilities of the device, namely:
 - "s-stage": enable s-stage support
 - "g-stage": enable g-stage support
 
+riscv-iommu-sys device
+----------------------
+
+This device implements the RISC-V IOMMU emulation as a platform bus device that
+RISC-V boards can use.
+
+For the 'virt' board the device is disabled by default.  To enable it use the
+'iommu-sys' machine option:
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 -M virt,iommu-sys=on (...)
+
+There is no options to configure the capabilities of this device in the 'virt'
+board using the QEMU command line.  The device is configured with the following
+riscv-iommu options:
+
+- "ioatc-limit": default value (2Mb)
+- "intremap": enabled
+- "ats": enabled
+- "off": on (DMA disabled)
+- "s-stage": enabled
+- "g-stage": enabled
+
 .. _iommu1.0: https://github.com/riscv-non-isa/riscv-iommu/releases/download/v1.0/riscv-iommu.pdf
 
 .. _linux-v8: https://lore.kernel.org/linux-riscv/cover.1718388908.git.tjeznach@rivosinc.com/