Hi Stefano, On 2/5/19 7:14 PM, Paolo Bonzini wrote: > From: Stefano Garzarella <sgarz...@redhat.com> > > The new pvh.bin option rom can be used with SeaBIOS to boot > uncompressed kernel using the x86/HVM direct boot ABI. > > pvh.S contains the entry point of the option rom. It runs > in real mode, loads the e820 table querying the BIOS, and > then it switches to 32bit protected mode and jumps to the > pvh_load_kernel() written in pvh_main.c. > pvh_load_kernel() loads the cmdline and kernel entry_point > using fw_cfg, then it looks for RSDP, fills the > hvm_start_info required by x86/HVM ABI, and finally jumps > to the kernel entry_point. > > Signed-off-by: Stefano Garzarella <sgarz...@redhat.com> > Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> > Reviewed-by: Liam Merwick <liam.merw...@oracle.com> > --- > .gitignore | 4 + > Makefile | 2 +- > pc-bios/optionrom/Makefile | 5 +- > pc-bios/optionrom/pvh.S | 200 > +++++++++++++++++++++++++++++++++++++++++++ > pc-bios/optionrom/pvh_main.c | 116 +++++++++++++++++++++++++ > pc-bios/pvh.bin | Bin 0 -> 1536 bytes > 6 files changed, 325 insertions(+), 2 deletions(-) > create mode 100644 pc-bios/optionrom/pvh.S > create mode 100644 pc-bios/optionrom/pvh_main.c > create mode 100644 pc-bios/pvh.bin
> +++ b/pc-bios/optionrom/Makefile > @@ -37,7 +37,7 @@ Wa = -Wa, > ASFLAGS += -32 > QEMU_CFLAGS += $(call cc-c-option, $(QEMU_CFLAGS), $(Wa)-32) > > -build-all: multiboot.bin linuxboot.bin linuxboot_dma.bin kvmvapic.bin > +build-all: multiboot.bin linuxboot.bin linuxboot_dma.bin kvmvapic.bin pvh.bin > > +++ b/pc-bios/optionrom/pvh_main.c > @@ -0,0 +1,116 @@ > +/* > + * PVH Option ROM for fw_cfg DMA > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, see <http://www.gnu.org/licenses/>. > + * > + * Copyright (c) 2019 Red Hat Inc. > + * Authors: > + * Stefano Garzarella <sgarz...@redhat.com> > + */ > + > +asm (".code32"); /* this code will be executed in protected mode */ > + > +#include <stddef.h> > +#include <stdint.h> > +#include "optrom.h" > +#include "optrom_fw_cfg.h" > +#include "../../include/hw/xen/start_info.h" > + > +#define RSDP_SIGNATURE 0x2052545020445352LL /* "RSD PTR " */ > +#define RSDP_AREA_ADDR 0x000E0000 > +#define RSDP_AREA_SIZE 2048 > +#define EBDA_BASE_ADDR 0x0000040E > +#define EBDA_SIZE 1024 > + > +#define E820_MAXENTRIES 128 > +#define CMDLINE_BUFSIZE 4096 > + > +/* e820 table filled in pvh.S using int 0x15 */ > +struct pvh_e820_table { > + uint32_t entries; > + uint32_t reserved; > + struct hvm_memmap_table_entry table[E820_MAXENTRIES]; > +}; > + > +struct pvh_e820_table pvh_e820 asm("pvh_e820") __attribute__ ((aligned)); > + > +static struct hvm_start_info start_info; > +static uint8_t cmdline_buffer[CMDLINE_BUFSIZE]; > + > + > +/* Search RSDP signature. */ > +static uintptr_t search_rsdp(uint32_t start_addr, uint32_t end_addr) > +{ > + uint64_t *rsdp_p; > + > + /* RSDP signature is always on a 16 byte boundary */ > + for (rsdp_p = (uint64_t *)start_addr; rsdp_p < (uint64_t *)end_addr; > + rsdp_p += 2) { > + if (*rsdp_p == RSDP_SIGNATURE) { > + return (uintptr_t)rsdp_p; > + } > + } > + > + return 0; > +} gcc 10.2.1 "cc (Alpine 10.2.1_pre2) 10.2.1 20210313" reports: pc-bios/optionrom/pvh_main.c: In function 'search_rsdp': pc-bios/optionrom/pvh_main.c:61:21: warning: comparison is always false due to limited range of data type [-Wtype-limits] 61 | if (*rsdp_p == RSDP_SIGNATURE) { | ^~ Can you have a look? Thanks, Phil.
