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Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size
From: |
Xiang Zheng |
Subject: |
Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory |
Date: |
Fri, 12 Apr 2019 09:52:44 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:64.0) Gecko/20100101 Thunderbird/64.0 |
On 2019/4/11 20:22, Kevin Wolf wrote:
> Okay, so your problem is that blk_pread() writes to the whole buffer,
> writing explicit zeroes for unallocated parts of the image, while you
> would like to leave those parts of the buffer untouched so that we don't
> actually allocate the memory, but can just use the shared zero page.
>
> If you just want to read the non-zero parts of the image, that can be
> done by using a loop that calls bdrv_block_status() and only reads from
> the image if the BDRV_BLOCK_ZERO bit is clear.
>
> Would this solve your problem?
Sounds good! What if guest tried to read/write the zero parts?
--
Thanks,
Xiang
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Markus Armbruster, 2019/04/09
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Kevin Wolf, 2019/04/09
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Xiang Zheng, 2019/04/10
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Kevin Wolf, 2019/04/11
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory,
Xiang Zheng <=
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Xiang Zheng, 2019/04/12
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Kevin Wolf, 2019/04/12
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Xiang Zheng, 2019/04/14
- Re: [Qemu-block] [Qemu-devel] [RFC PATCH] hw/arm/virt: use variable size of flash device to save memory, Xiang Zheng, 2019/04/21