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Re: [PULL 03/38] pflash: Only read non-zero parts of backend image
From: |
Cédric Le Goater |
Subject: |
Re: [PULL 03/38] pflash: Only read non-zero parts of backend image |
Date: |
Mon, 6 Feb 2023 16:54:46 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 |
Hello,
On 1/20/23 13:25, Kevin Wolf wrote:
From: Xiang Zheng <zhengxiang9@huawei.com>
Currently we fill the VIRT_FLASH memory space with two 64MB NOR images
when using persistent UEFI variables on virt board. Actually we only use
a very small(non-zero) part of the memory while the rest significant
large(zero) part of memory is wasted.
So this patch checks the block status and only writes the non-zero part
into memory. This requires pflash devices to use sparse files for
backends.
Signed-off-by: Xiang Zheng <zhengxiang9@huawei.com>
[ kraxel: rebased to latest master ]
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20221220084246.1984871-1-kraxel@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This newly merged patch introduces a "regression" when booting an Aspeed
machine. The following extra m25p80 patch (not yet merged) is required
for the issue to show:
https://lore.kernel.org/qemu-devel/20221115151000.2080833-1-clg@kaod.org/
U-Boot fails to find the filesystem in that case.
It can be easily reproduced with the witherspoon-bmc machine and seems
to be related to the use of a UBI filesystem. Other Aspeed machines not
using UBI are not impacted.
Here is a tentative fix. I don't know enough the block layer to explain
what is happening :/
Thanks,
C.
@@ -39,7 +39,7 @@ static int blk_pread_nonzeroes(BlockBack
return ret;
}
if (!(ret & BDRV_BLOCK_ZERO)) {
- ret = bdrv_pread(bs->file, offset, bytes,
+ ret = blk_pread(blk, offset, bytes,
(uint8_t *) buf + offset, 0);
if (ret < 0) {
return ret;
- Re: [PULL 03/38] pflash: Only read non-zero parts of backend image,
Cédric Le Goater <=