Re: [PATCH qemu] m68k: virt: pass RNG seed via bootinfo block

[Laurent Vivier]

Le 25/06/2022 à 17:44, Jason A. Donenfeld a écrit :
> 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-Jason@zx2c4.com/
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> This requires this trivial cleanup commit first:
>      20220625152318.120849-1-Jason@zx2c4.com/">https://lore.kernel.org/qemu-devel/20220625152318.120849-1-Jason@zx2c4.com/

For patchew, the syntax is:

Based-on: <20220625152318.120849-1-Jason@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)
>   

Reviewed-by: Laurent Vivier <laurent@vivier.eu>