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Re: [Qemu-trivial] [Qemu-devel] [PATCH] Fix pflash_cfi01 to restore flas
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-trivial] [Qemu-devel] [PATCH] Fix pflash_cfi01 to restore flash command/array state after migration |
Date: |
Thu, 21 Aug 2014 11:48:08 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
I'm afraid this is *not* trivial. Migration stuff rarely is :)
Johny Mattsson <address@hidden> writes:
> When using snapshots on e.g. the VersatilePB board, the pflash driver
> would report an error and get reset at times after resuming the snapshot.
> This was traced down to the 'romd' flag in the pflash emulation which was
> not being persisted in the snapshot.
>
> Author: Bernd Meyer <address@hidden>
> Signed-off-by: Johny Mattsson <address@hidden>
>
> ---
> hw/block/pflash_cfi01.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
> index f9507b4..83cb1d3 100644
> --- a/hw/block/pflash_cfi01.c
> +++ b/hw/block/pflash_cfi01.c
> @@ -80,6 +80,7 @@ struct pflash_t {
> int ro;
> uint8_t cmd;
> uint8_t status;
> + uint8_t romd;
> uint16_t ident0;
> uint16_t ident1;
> uint16_t ident2;
> @@ -94,14 +95,25 @@ struct pflash_t {
> void *storage;
> };
>
> +static int sync_romd(void* opaque, int version_id)
> +{
> + (void)version_id;
> + pflash_t *pfl = opaque;
> +
> + memory_region_rom_device_set_romd(&pfl->mem,!!pfl->romd);
> + return 0;
> +}
> +
> static const VMStateDescription vmstate_pflash = {
> .name = "pflash_cfi01",
> .version_id = 1,
> .minimum_version_id = 1,
> + .post_load = sync_romd,
> .fields = (VMStateField[]) {
> VMSTATE_UINT8(wcycle, pflash_t),
> VMSTATE_UINT8(cmd, pflash_t),
> VMSTATE_UINT8(status, pflash_t),
> + VMSTATE_UINT8(romd, pflash_t),
> VMSTATE_UINT64(counter, pflash_t),
> VMSTATE_END_OF_LIST()
> }
Doesn't this break migration to/from unfixed versions?
> @@ -114,6 +126,7 @@ static void pflash_timer (void *opaque)
> DPRINTF("%s: command %02x done\n", __func__, pfl->cmd);
> /* Reset flash */
> pfl->status ^= 0x80;
> + pfl->romd=1;
> memory_region_rom_device_set_romd(&pfl->mem, true);
> pfl->wcycle = 0;
> pfl->cmd = 0;
> @@ -453,6 +466,7 @@ static void pflash_write(pflash_t *pfl, hwaddr offset,
>
> if (!pfl->wcycle) {
> /* Set the device in I/O access mode */
> + pfl->romd=0;
> memory_region_rom_device_set_romd(&pfl->mem, false);
> }
>
> @@ -638,6 +652,7 @@ static void pflash_write(pflash_t *pfl, hwaddr offset,
> "\n", __func__, offset, pfl->wcycle, pfl->cmd, value);
>
> reset_flash:
> + pfl->romd=1;
> memory_region_rom_device_set_romd(&pfl->mem, true);
>
> pfl->wcycle = 0;
> @@ -804,6 +819,7 @@ static void pflash_cfi01_realize(DeviceState *dev,
> Error **errp)
> pfl->wcycle = 0;
> pfl->cmd = 0;
> pfl->status = 0;
> + pfl->romd = 1;
> /* Hardcoded CFI table */
> pfl->cfi_len = 0x52;
> /* Standard "QRY" string */
> --
> 2.0.0
I suspect you need a subsection. Initialize ->romd = 1, then let the
subsection override it.