Michael S. Tsirkin <m...@redhat.com> 于2023年1月30日周一 23:07写道：
>
> On Mon, Jan 30, 2023 at 10:47:25PM +0800, Feng Sun wrote:
> > Igor Mammedov <imamm...@redhat.com> 于2023年1月24日周二 18:30写道：
> > >
> > > On Tue, 17 Jan 2023 19:15:21 +0800
> > > Sun Feng <loyo...@gmail.com> wrote:
> > >
> > > > Migrate from aarch64 host with PAGE_SIZE 64k to 4k failed with
> > > > following errors:
> > > >
> > > > qmp_cmd_name: migrate-incoming, arguments: {"uri": "tcp:[::]:49152"}
> > > > {"timestamp": {"seconds": 1673922775, "microseconds": 534702}, "event":
> > > > "MIGRATION", "data": {"status": "setup"}}
> > > > {"timestamp": {"seconds": 1673922776, "microseconds": 53003}, "event":
> > > > "MIGRATION", "data": {"status": "active"}}
> > > > 2023-01-17T02:32:56.058827Z qemu-system-aarch64: Length too large:
> > > > /rom@etc/acpi/rsdp: 0x10000 > 0x1000: Invalid argument
> > >
> > > this should mention/explain why it's happening.
> > >
> > > i.e we now have 4k limit for RSDP, but then source somehow managed to
> > > start with 64k
> > > allocated to for RSDP. It looks like limit isn't working as expected to
> > > me.
> >
> > 4k limit should be romsize limit. I can see Rom '/rom@etc/acpi/rsdp'
> > with romsize:4096, datasize:36.
> > RAMBlock's used_length is set with datasize aligned to PAGE_SIZE, so
> > it become 64k when PAGE_SIZE is 64k.
> > ```
> > static
> > RAMBlock *qemu_ram_alloc_internal(ram_addr_t size, ram_addr_t max_size,
> > void (*resized)(const char*,
> > uint64_t length,
> > void *host),
> > void *host, uint32_t ram_flags,
> > MemoryRegion *mr, Error **errp)
> > {
> > RAMBlock *new_block;
> > Error *local_err = NULL;
> >
> > assert((ram_flags & ~(RAM_SHARED | RAM_RESIZEABLE | RAM_PREALLOC |
> > RAM_NORESERVE)) == 0);
> > assert(!host ^ (ram_flags & RAM_PREALLOC));
> >
> > size = HOST_PAGE_ALIGN(size);
> > max_size = HOST_PAGE_ALIGN(max_size);
> > new_block = g_malloc0(sizeof(*new_block));
> > new_block->mr = mr;
> > new_block->resized = resized;
> > new_block->used_length = size;
> > ```
> > So when migrate to 4k PAGE_SIZE, it will report the errors.
> >
> > ramblock information for PAGE_SIZE 64k and 4k.
> > ```
> > # getconf PAGE_SIZE
> > 65536
> > # virsh qemu-monitor-command testvm --hmp 'info ramblock'
> > Block Name PSize Offset
> > Used Total
> > mach-virt.ram 64 KiB 0x0000000000000000
> > 0x0000000040000000 0x0000000040000000
> > virt.flash0 64 KiB 0x0000000040000000
> > 0x0000000004000000 0x0000000004000000
> > virt.flash1 64 KiB 0x0000000044000000
> > 0x0000000004000000 0x0000000004000000
> > /rom@etc/acpi/tables 64 KiB 0x0000000048040000
> > 0x0000000000020000 0x0000000000200000
> > 0000:00:01.2:00.0/virtio-net-pci.rom 64 KiB 0x0000000048000000
> > 0x0000000000040000 0x0000000000040000
> > /rom@etc/table-loader 64 KiB 0x0000000048240000
> > 0x0000000000010000 0x0000000000010000
> > /rom@etc/acpi/rsdp 64 KiB 0x0000000048280000
> > 0x0000000000010000 0x0000000000010000
> >
> > # getconf PAGE_SIZE
> > 4096
> > # virsh qemu-monitor-command testvm --hmp 'info ramblock'
> > Block Name PSize Offset
> > Used Total
> > mach-virt.ram 4 KiB 0x0000000000000000
> > 0x0000000800000000 0x0000000800000000
> > virt.flash0 4 KiB 0x0000000800000000
> > 0x0000000004000000 0x0000000004000000
> > virt.flash1 4 KiB 0x0000000804000000
> > 0x0000000004000000 0x0000000004000000
> > /rom@etc/acpi/tables 4 KiB 0x0000000808000000
> > 0x0000000000020000 0x0000000000200000
> > /rom@etc/table-loader 4 KiB 0x0000000808200000
> > 0x0000000000001000 0x0000000000010000
> > /rom@etc/acpi/rsdp 4 KiB 0x0000000808240000
> > 0x0000000000001000 0x0000000000001000
> > ```
>
> Oh interesting. I don't remember why I decided to align in.
> What does the following do (warning: completely untested):
>
>
> diff --git a/softmmu/physmem.c b/softmmu/physmem.c
> index cb998cdf23..5c732101b9 100644
> --- a/softmmu/physmem.c
> +++ b/softmmu/physmem.c
> @@ -2154,7 +2154,7 @@ RAMBlock *qemu_ram_alloc_internal(ram_addr_t size,
> ram_addr_t max_size,
> RAM_NORESERVE)) == 0);
> assert(!host ^ (ram_flags & RAM_PREALLOC));
>
> - size = HOST_PAGE_ALIGN(size);
> + // size = HOST_PAGE_ALIGN(size);
> max_size = HOST_PAGE_ALIGN(max_size);
> new_block = g_malloc0(sizeof(*new_block));
> new_block->mr = mr;
>
With additional change we can see actually used size with 'info ramblock',
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1837,7 +1837,7 @@ int qemu_ram_resize(RAMBlock *block, ram_addr_t
newsize, Error **errp)
assert(block);
- newsize = HOST_PAGE_ALIGN(newsize);
+ //newsize = HOST_PAGE_ALIGN(newsize);
if (block->used_length == newsize) {
/*
# virsh qemu-monitor-command testvm --hmp 'info ramblock'
Block Name PSize Offset
Used Total
mach-virt.ram 64 KiB 0x0000000000000000
0x0000000800000000 0x0000000800000000
virt.flash0 64 KiB 0x0000000800000000
0x0000000004000000 0x0000000004000000
virt.flash1 64 KiB 0x0000000804000000
0x0000000004000000 0x0000000004000000
/rom@etc/acpi/tables 64 KiB 0x0000000808000000
0x0000000000020000 0x0000000000200000
/rom@etc/table-loader 64 KiB 0x0000000808200000
0x0000000000000b00 0x0000000000010000
/rom@etc/acpi/rsdp 64 KiB 0x0000000808240000
0x0000000000000024 0x0000000000010000
but migration needs more changes. I fixed the following error during migration:
qemu-system-aarch64: ../softmmu/physmem.c:1059:
cpu_physical_memory_test_and_clear_dirty: Assertion `start >=
ramblock->offset && start + length <= ramblock->offset +
ramblock->used_length' failed.
2023-01-31 04:09:40.934+0000: shutting down, reason=crashed
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1055,7 +1055,7 @@ bool
cpu_physical_memory_test_and_clear_dirty(ram_addr_t start,
ramblock = qemu_get_ram_block(start);
/* Range sanity check on the ramblock */
assert(start >= ramblock->offset &&
- start + length <= ramblock->offset + ramblock->used_length);
+ start + length <= ramblock->offset + ramblock->max_length);
while (page < end) {
unsigned long idx = page / DIRTY_MEMORY_BLOCK_SIZE;
but more issues still exist,
source:
2023-01-31T05:23:28.051615Z qemu-system-aarch64: failed to save
SaveStateEntry with id(name): 3(ram): -5
2023-01-31T05:23:28.053256Z qemu-system-aarch64: Unable to write to
socket: Bad file descriptor
target:
2023-01-31T05:23:28.049659Z qemu-system-aarch64: Received an
unexpected compressed page
2023-01-31T05:23:28.049709Z qemu-system-aarch64: error while loading
state for instance 0x0 of device 'ram'
2023-01-31T05:23:28.050095Z qemu-system-aarch64: load of migration
failed: Invalid argument
In my opinion, it would be a tricky way to set 64k and would not have
migration compatibility problems.
Of course, the best and appropriate way is to migrate with actual data size.
I am not quite familiar with migration codes, if needed, I can help to
do more migration patch tests.
