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_vars> -pflash <smode_fw_code> -machine virt or qemu-system-riscv64 -bios <opensbi_fw> \ -pflash <smode_fw_vars> \ -pflash <smode_fw_code> \ -machine virt or qemu-system-riscv64 -bios <opensbi_fw> \ -drive file=<smode_fw_vars>,if=pflash,format=raw,unit=0 \ -drive file=<smode_fw_code>,if=pflash,format=raw,unit=1,readonly=on \ -machine virt Signed-off-by: Sunil V L <suni...@ventanamicro.com> Reported-by: Heinrich Schuchardt <xypron.g...@gmx.de> --- The issue is reported at https://salsa.debian.org/qemu-team/edk2/-/commit/c345655a0149f64c5020bfc1e53c619ce60587f6 The patch is based on Alistair's riscv-to-apply.next branch. Changes since v1: 1) Simplified the fix such that it doesn't break current EDK2. hw/riscv/virt.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c index 4e3efbee16..ca445d3d02 100644 --- a/hw/riscv/virt.c +++ b/hw/riscv/virt.c @@ -1296,10 +1296,11 @@ static void virt_machine_done(Notifier *notifier, void *data) kernel_entry = 0; } - if (drive_get(IF_PFLASH, 0, 0)) { + if (drive_get(IF_PFLASH, 0, 0) && + machine->firmware && !strcmp(machine->firmware, "none")) { /* - * Pflash was supplied, let's overwrite the address we jump to after - * reset to the base of the flash. + * Pflash0 was supplied with "-bios none", let's overwrite the address + * we jump to after reset to the base of the flash. */ start_addr = virt_memmap[VIRT_FLASH].base; } -- 2.34.1