On Fri, Apr 21, 2023 at 12:39:46PM +0800, Bin Meng wrote: > On Fri, Apr 21, 2023 at 12:34 PM Sunil V L <suni...@ventanamicro.com> wrote: > > > > Currently, virt machine supports two pflash instances each with > > 32MB size. However, the first pflash is always assumed to > > contain M-mode firmware and reset vector is set to this if > > enabled. Hence, for S-mode payloads like EDK2, only one pflash > > instance is available for use. This means both code and NV variables > > of EDK2 will need to use the same pflash. > > > > The OS distros keep the EDK2 FW code as readonly. When non-volatile > > variables also need to share the same pflash, it is not possible > > to keep it as readonly since variables need write access. > > > > To resolve this issue, the code and NV variables need to be separated. > > But in that case we need an extra flash. Hence, modify the convention > > such that pflash0 will contain the M-mode FW only when "-bios none" > > option is used. Otherwise, pflash0 will contain the S-mode payload FW. > > This enables both pflash instances available for EDK2 use. > > > > Example usage: > > 1) pflash0 containing M-mode FW > > qemu-system-riscv64 -bios none -pflash <mmode_fw> -machine virt > > or > > qemu-system-riscv64 -bios none \ > > -drive file=<mmode_fw>,if=pflash,format=raw,unit=0 -machine virt > > > > 2) pflash0 containing S-mode payload like EDK2 > > qemu-system-riscv64 -pflash <smode_fw_code> -pflash <smode_vars> -machine > > virt > > or > > qemu-system-riscv64 -bios <opensbi_fw> \ > > -pflash <smode_fw_code> \ > > -pflash <smode_vars> \ > > -machine virt > > or > > qemu-system-riscv64 -bios <opensbi_fw> \ > > -drive file=<smode_fw_code>,if=pflash,format=raw,unit=0,readonly=on \ > > -drive file=<smode_fw_vars>,if=pflash,format=raw,unit=1 \ > > -machine virt > > Please update the docs in docs/system/riscv/virt.rst to include how to > run EDK2 bios with these settings. > Thanks Bin. Shall I do it as a separate patch after this gets approved? The reason is, I need to make changes in EDK2 to work with this. Once EDK2 changes are also in place, will send a patch to update this documentation. Does it make sense?
Thanks, Sunil