This reverts 3824e25db1 ("x86: disable rng seeding via setup_data"), and
then makes the use of setup_data safe. It does so by checking the boot
protocol version. If it's sufficient, then it means EFI boots won't
crash. While we're at it, gate this on SEV too.Cc: Gerd Hoffmann <[email protected]> Cc: Laurent Vivier <[email protected]> Cc: Michael S. Tsirkin <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Peter Maydell <[email protected]> Cc: Philippe Mathieu-Daudé <[email protected]> Cc: Richard Henderson <[email protected]> Cc: Ard Biesheuvel <[email protected]> Signed-off-by: Jason A. Donenfeld <[email protected]> --- hw/i386/microvm.c | 2 +- hw/i386/pc_piix.c | 2 +- hw/i386/pc_q35.c | 2 +- hw/i386/x86.c | 11 +++++++++-- 4 files changed, 12 insertions(+), 5 deletions(-) diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c index 52cafa003d..7fe8cce03e 100644 --- a/hw/i386/microvm.c +++ b/hw/i386/microvm.c @@ -332,7 +332,7 @@ static void microvm_memory_init(MicrovmMachineState *mms) rom_set_fw(fw_cfg); if (machine->kernel_filename != NULL) { - x86_load_linux(x86ms, fw_cfg, 0, true, true); + x86_load_linux(x86ms, fw_cfg, 0, true, false); } if (mms->option_roms) { diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index 8043a250ad..ed7007672b 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -439,7 +439,6 @@ static void pc_i440fx_7_2_machine_options(MachineClass *m) m->alias = "pc"; m->is_default = true; pcmc->default_cpu_version = 1; - pcmc->legacy_no_rng_seed = true; } DEFINE_I440FX_MACHINE(v7_2, "pc-i440fx-7.2", NULL, @@ -463,6 +462,7 @@ static void pc_i440fx_7_0_machine_options(MachineClass *m) pc_i440fx_7_1_machine_options(m); m->alias = NULL; m->is_default = false; + pcmc->legacy_no_rng_seed = true; pcmc->enforce_amd_1tb_hole = false; compat_props_add(m->compat_props, hw_compat_7_0, hw_compat_7_0_len); compat_props_add(m->compat_props, pc_compat_7_0, pc_compat_7_0_len); diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index 53eda50e81..3ffb40f8f0 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -376,7 +376,6 @@ static void pc_q35_7_2_machine_options(MachineClass *m) pc_q35_machine_options(m); m->alias = "q35"; pcmc->default_cpu_version = 1; - pcmc->legacy_no_rng_seed = true; } DEFINE_Q35_MACHINE(v7_2, "pc-q35-7.2", NULL, @@ -398,6 +397,7 @@ static void pc_q35_7_0_machine_options(MachineClass *m) PCMachineClass *pcmc = PC_MACHINE_CLASS(m); pc_q35_7_1_machine_options(m); m->alias = NULL; + pcmc->legacy_no_rng_seed = true; pcmc->enforce_amd_1tb_hole = false; compat_props_add(m->compat_props, hw_compat_7_0, hw_compat_7_0_len); compat_props_add(m->compat_props, pc_compat_7_0, pc_compat_7_0_len); diff --git a/hw/i386/x86.c b/hw/i386/x86.c index 050eedc0c8..fddc20df03 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -1088,8 +1088,15 @@ void x86_load_linux(X86MachineState *x86ms, qemu_guest_getrandom_nofail(setup_data->data, RNG_SEED_LENGTH); } - /* Offset 0x250 is a pointer to the first setup_data link. */ - stq_p(header + 0x250, first_setup_data); + /* + * Only modify the header if doing so won't crash EFI boot, which is the + * case only for newer boot protocols, and don't do so either if SEV is + * enabled. + */ + if (protocol >= 0x210 && !sev_enabled()) { + /* Offset 0x250 is a pointer to the first setup_data link. */ + stq_p(header + 0x250, first_setup_data); + } /* * If we're starting an encrypted VM, it will be OVMF based, which uses the -- 2.37.3
