This commit wires up bootinfo's RNG seed attribute so that Linux VMs can have their RNG seeded from the earliest possible time in boot, just like the "rng-seed" device tree property on those platforms. The link contains the corresponding Linux patch.
Link: https://lore.kernel.org/lkml/20220625153841.143928-1-ja...@zx2c4.com/ Signed-off-by: Jason A. Donenfeld <ja...@zx2c4.com> --- This requires this trivial cleanup commit first: https://lore.kernel.org/qemu-devel/20220625152318.120849-1-ja...@zx2c4.com/ hw/m68k/bootinfo.h | 16 ++++++++++++++++ hw/m68k/virt.c | 7 +++++++ .../standard-headers/asm-m68k/bootinfo-virt.h | 1 + 3 files changed, 24 insertions(+) diff --git a/hw/m68k/bootinfo.h b/hw/m68k/bootinfo.h index ff4e155a3c..2f31c13b6e 100644 --- a/hw/m68k/bootinfo.h +++ b/hw/m68k/bootinfo.h @@ -56,4 +56,20 @@ stb_phys(as, base++, 0); \ base = (base + 1) & ~1; \ } while (0) + +#define BOOTINFODATA(as, base, id, data, len) \ + do { \ + int i; \ + stw_phys(as, base, id); \ + base += 2; \ + stw_phys(as, base, \ + (sizeof(struct bi_record) + len + 5) & ~1); \ + base += 2; \ + stl_phys(as, base, len); \ + base += 4; \ + for (i = 0; i < len; ++i) { \ + stb_phys(as, base++, data[i]); \ + } \ + base = (base + 1) & ~1; \ + } while (0) #endif diff --git a/hw/m68k/virt.c b/hw/m68k/virt.c index e215aa3d42..0aa383fa6b 100644 --- a/hw/m68k/virt.c +++ b/hw/m68k/virt.c @@ -9,6 +9,7 @@ #include "qemu/osdep.h" #include "qemu/units.h" +#include "qemu/guest-random.h" #include "sysemu/sysemu.h" #include "cpu.h" #include "hw/boards.h" @@ -120,6 +121,7 @@ static void virt_init(MachineState *machine) hwaddr io_base; int i; ResetInfo *reset_info; + uint8_t rng_seed[32]; if (ram_size > 3399672 * KiB) { /* @@ -245,6 +247,11 @@ static void virt_init(MachineState *machine) kernel_cmdline); } + /* Pass seed to RNG. */ + qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed)); + BOOTINFODATA(cs->as, parameters_base, BI_VIRT_RNG_SEED, + rng_seed, sizeof(rng_seed)); + /* load initrd */ if (initrd_filename) { initrd_size = get_image_size(initrd_filename); diff --git a/include/standard-headers/asm-m68k/bootinfo-virt.h b/include/standard-headers/asm-m68k/bootinfo-virt.h index 81be1e0924..1b1ffd4705 100644 --- a/include/standard-headers/asm-m68k/bootinfo-virt.h +++ b/include/standard-headers/asm-m68k/bootinfo-virt.h @@ -12,6 +12,7 @@ #define BI_VIRT_GF_TTY_BASE 0x8003 #define BI_VIRT_VIRTIO_BASE 0x8004 #define BI_VIRT_CTRL_BASE 0x8005 +#define BI_VIRT_RNG_SEED 0x8006 #define VIRT_BOOTI_VERSION MK_BI_VERSION(2, 0) -- 2.35.1
