This patch allows the user to usefully specify -drive file=img_1,if=pflash,format=raw,readonly \ -drive file=img_2,if=pflash,format=raw
on the command line. The flash images will be mapped under 4G in their reverse unit order -- that is, with their base addresses progressing downwards, in increasing unit order. (The unit number increases with command line order if not explicitly specified.) This accommodates the following use case: suppose that OVMF is split in two parts, a writeable host file for non-volatile variable storage, and a read-only part for bootstrap and decompressible executable code. The binary code part would be read-only, centrally managed on the host system, and passed in as unit 0. The variable store would be writeable, VM-specific, and passed in as unit 1. 00000000ffe00000-00000000ffe1ffff (prio 0, R-): system.flash1 00000000ffe20000-00000000ffffffff (prio 0, R-): system.flash0 (If the guest tries to write to the flash range that is backed by the read-only drive, bdrv_write() in pflash_update() will correctly deny the write with -EACCES, and pflash_update() won't care, which suits us well.) Signed-off-by: Laszlo Ersek <ler...@redhat.com> --- hw/i386/pc_sysfw.c | 60 ++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 45 insertions(+), 15 deletions(-) diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c index e917c83..1c3e3d6 100644 --- a/hw/i386/pc_sysfw.c +++ b/hw/i386/pc_sysfw.c @@ -72,35 +72,65 @@ static void pc_isa_bios_init(MemoryRegion *rom_memory, memory_region_set_readonly(isa_bios, true); } +/* This function maps flash drives from 4G downward, in order of their unit + * numbers. Addressing within one flash drive is of course not reversed. + * + * The drive with unit number 0 is mapped at the highest address, and it is + * passed to pc_isa_bios_init(). Merging severral drives for isa-bios is not + * supported. + * + * The caller is responsible to pass in the non-NULL @pflash_drv that + * corresponds to the flash drive with unit number 0. + */ static void pc_system_flash_init(MemoryRegion *rom_memory, DriveInfo *pflash_drv) { + int unit = 0; BlockDriverState *bdrv; int64_t size; - hwaddr phys_addr; + hwaddr phys_addr = 0x100000000ULL; int sector_bits, sector_size; pflash_t *system_flash; MemoryRegion *flash_mem; + char name[64]; - bdrv = pflash_drv->bdrv; - size = bdrv_getlength(pflash_drv->bdrv); sector_bits = 12; sector_size = 1 << sector_bits; - if ((size % sector_size) != 0) { - fprintf(stderr, - "qemu: PC system firmware (pflash) must be a multiple of 0x%x\n", - sector_size); - exit(1); - } + do { + bdrv = pflash_drv->bdrv; + size = bdrv_getlength(bdrv); + if ((size % sector_size) != 0) { + fprintf(stderr, + "qemu: PC system firmware (pflash segment %d) must be a " + "multiple of 0x%x\n", unit, sector_size); + exit(1); + } + if (size > phys_addr) { + fprintf(stderr, "qemu: pflash segments must fit under 4G " + "cumulatively\n"); + exit(1); + } - phys_addr = 0x100000000ULL - size; - system_flash = pflash_cfi01_register(phys_addr, NULL, "system.flash", size, - bdrv, sector_size, size >> sector_bits, - 1, 0x0000, 0x0000, 0x0000, 0x0000, 0); - flash_mem = pflash_cfi01_get_memory(system_flash); + phys_addr -= size; - pc_isa_bios_init(rom_memory, flash_mem, size); + /* pflash_cfi01_register() creates a deep copy of the name */ + snprintf(name, sizeof name, "system.flash%d", unit); + system_flash = pflash_cfi01_register(phys_addr, NULL /* qdev */, name, + size, bdrv, sector_size, + size >> sector_bits, + 1 /* width */, + 0x0000 /* id0 */, + 0x0000 /* id1 */, + 0x0000 /* id2 */, + 0x0000 /* id3 */, + 0 /* be */); + if (unit == 0) { + flash_mem = pflash_cfi01_get_memory(system_flash); + pc_isa_bios_init(rom_memory, flash_mem, size); + } + pflash_drv = drive_get(IF_PFLASH, 0, ++unit); + } while (pflash_drv != NULL); } static void old_pc_system_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw) -- 1.8.3.1