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
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
------------------------
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]
To test 32-bit U-Boot images, switch to use qemu-riscv32_smode_defconfig and
riscv32_spl_defconfig builds, and replace ``qemu-system-riscv64`` with
``qemu-system-riscv32`` in the command lines above to boot the 32-bit U-Boot.
+
+Enabling TPM
+------------
+
+A TPM device can be connected to the virt board by following the steps below.
+
+First launch the TPM emulator:
+
+.. code-block:: bash
+
+ $ swtpm socket --tpm2 -t -d --tpmstate dir=/tmp/tpm \
+ --ctrl type=unixio,path=swtpm-sock
+
+Then launch QEMU with some additional arguments to link a TPM device to the backend:
+
+.. code-block:: bash
+
+ $ qemu-system-riscv64 \
+ ... other args .... \
+ -chardev socket,id=chrtpm,path=swtpm-sock \
+ -tpmdev emulator,id=tpm0,chardev=chrtpm \
+ -device tpm-tis-device,tpmdev=tpm0
+
+The TPM device can be seen in the memory tree and the generated device
+tree and should be accessible from the guest software.