Merge tag 'pull-target-arm-20240111' of https://git.linaro.org/people/pmaydell/qemu...

[mirror_qemu.git] / docs / system / riscv / virt.rst

diff --git a/docs/system/riscv/virt.rst b/docs/system/riscv/virt.rst
index 4b16e41d7f58a01519b0197f4ef6aefc2e24ea38..9a06f95a3444c1eb2e49b09d6821c3a943980687 100644 (file)
--- a/docs/system/riscv/virt.rst
+++ b/docs/system/riscv/virt.rst
@@ -12,7 +12,7 @@ Supported devices
 
 The ``virt`` machine supports the following devices:
 
-* Up to 8 generic RV32GC/RV64GC cores, with optional extensions
+* Up to 512 generic RV32GC/RV64GC cores, with optional extensions
 * Core Local Interruptor (CLINT)
 * Platform-Level Interrupt Controller (PLIC)
 * CFI parallel NOR flash memory
@@ -53,6 +53,37 @@ with the default OpenSBI firmware image as the -bios. It also supports
 the recommended RISC-V bootflow: U-Boot SPL (M-mode) loads OpenSBI fw_dynamic
 firmware and U-Boot proper (S-mode), using the standard -bios functionality.
 
+Using flash devices
+-------------------
+
+By default, the first flash device (pflash0) is expected to contain
+S-mode firmware code. It can be configured as read-only, with the
+second flash device (pflash1) available to store configuration data.
+
+For example, booting edk2 looks like
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 \
+     -blockdev node-name=pflash0,driver=file,read-only=on,filename=<edk2_code> \
+     -blockdev node-name=pflash1,driver=file,filename=<edk2_vars> \
+     -M virt,pflash0=pflash0,pflash1=pflash1 \
+     ... other args ....
+
+For TCG guests only, it is also possible to boot M-mode firmware from
+the first flash device (pflash0) by additionally passing ``-bios
+none``, as in
+
+.. code-block:: bash
+
+  $ qemu-system-riscv64 \
+     -bios none \
+     -blockdev node-name=pflash0,driver=file,read-only=on,filename=<m_mode_code> \
+     -M virt,pflash0=pflash0 \
+     ... other args ....
+
+Firmware images used for pflash must be exactly 32 MiB in size.
+
 Machine-specific options
 ------------------------
 
@@ -62,6 +93,12 @@ The following machine-specific options are supported:
 
   When this option is "on", ACLINT devices will be emulated instead of
   SiFive CLINT. When not specified, this option is assumed to be "off".
+  This option is restricted to the TCG accelerator.
+
+- acpi=[on|off|auto]
+
+  When this option is "on" (which is the default), ACPI tables are generated and
+  exposed as firmware tables etc/acpi/rsdp and etc/acpi/tables.
 
 - aia=[none|aplic|aplic-imsic]