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RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback
From: |
Shameerali Kolothum Thodi |
Subject: |
RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback |
Date: |
Thu, 6 Feb 2020 11:28:22 +0000 |
> -----Original Message-----
> From: David Hildenbrand [mailto:address@hidden]
> Sent: 06 February 2020 10:56
> To: Shameerali Kolothum Thodi <address@hidden>;
> Igor Mammedov <address@hidden>
> Cc: address@hidden; address@hidden;
> address@hidden; address@hidden; address@hidden;
> xuwei (O) <address@hidden>; Linuxarm <address@hidden>;
> address@hidden; address@hidden; address@hidden
> Subject: Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback
[...]
> > root@ubuntu:/# cat /dev/pmem
> > pmem0 pmem1
> >
> > From the logs, it looks like the ram_load_precopy() --> qemu_ram_resize() is
> not
> > called as length == used_length and both seems to be page aligned values.
> > And from
> https://github.com/qemu/qemu/blob/master/migration/ram.c#L3421
> > qemu_ram_resize() is called with length if length != used_length.
>
> Assume on your source, the old size is 12345 bytes. So 16384 aligned up
> (4 pages).
>
> Assume on your target, the new size is 123456 bytes, so 126976 aligned
> up (31 pages).
>
> If you migrate from source to destination, the migration code would
> resize to 16384, although the "actual size" is 12345. The callback will
> be called with the aligned size, not the actual size. Same the other way
> around. That's what's inconsistent IMHO.
Thanks. You are right. I didn’t consider the case where the target can be
configured with a larger number of devices than the source. I can replicate
the scenario now,
Source:
fw_cfg_add_file_callback: filename etc/boot-fail-wait size 0x4
fw_cfg_add_file_callback: filename etc/acpi/nvdimm-mem size 0x1000
fw_cfg_add_file_callback: filename etc/acpi/tables size 0x6210
Target:
ram_load_precopy: Ram blk mem1 length 0x40000000 used_length 0x40000000
ram_load_precopy: Ram blk virt.flash0 length 0x4000000 used_length 0x4000000
ram_load_precopy: Ram blk virt.flash1 length 0x4000000 used_length 0x4000000
ram_load_precopy: Ram blk /rom@etc/acpi/tables length 0x7000 used_length 0x8000
fw_cfg_modify_file: filename etc/acpi/tables len 0x7000
Target updates FWCfgEntry with a page aligned size :(. I will look into this
and see how
we can solve this. Any pointers welcome.
Cheers,
Shameer
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Igor Mammedov, 2020/02/04
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/04
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/04
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Shameerali Kolothum Thodi, 2020/02/05
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/05
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Shameerali Kolothum Thodi, 2020/02/06
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/06
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback,
Shameerali Kolothum Thodi <=
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/06
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Shameerali Kolothum Thodi, 2020/02/07
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/10
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Shameerali Kolothum Thodi, 2020/02/10
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/10
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Shameerali Kolothum Thodi, 2020/02/12
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/12
- RE: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, Shameerali Kolothum Thodi, 2020/02/13
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/13
- Re: [PATCH v2 1/7] exec: Fix for qemu_ram_resize() callback, David Hildenbrand, 2020/02/13