On 11.03.20 18:20, Shameer Kolothum wrote:
> From: David Hildenbrand <[email protected]>
>
> Summarizing the issue:
> 1. Memory regions contain ram blocks with a different size, if the
> size is not properly aligned. While memory regions can have an
> unaligned size, ram blocks can't. This is true when creating
> resizable memory region with an unaligned size.
> 2. When resizing a ram block/memory region, the size of the memory
> region is set to the aligned size. The callback is called with
> the aligned size. The unaligned piece is lost.
>
> Because of the above, if ACPI blob length modifications happens
> after the initial virt_acpi_build() call, and the changed blob
> length is within the PAGE size boundary, then the revised size
> is not seen by the firmware on Guest reboot.
>
> Hence make sure callback is called if memory region size is changed,
> irrespective of aligned or not.
>
> Signed-off-by: David Hildenbrand <[email protected]>
> [Shameer: added commit log]
> Signed-off-by: Shameer Kolothum <[email protected]>
> ---
> Please find the discussion here,
> https://patchwork.kernel.org/patch/11339591/
> ---
> exec.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 0cc500d53a..f8974cd303 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -2073,11 +2073,21 @@ static int memory_try_enable_merging(void *addr,
> size_t len)
> */
> int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
> {
> + const ram_addr_t unaligned_size = newsize;
> +
> assert(block);
>
> newsize = HOST_PAGE_ALIGN(newsize);
>
> if (block->used_length == newsize) {
> + /*
> + * We don't have to resize the ram block (which only knows aligned
> + * sizes), however, we have to notify if the unaligned size changed.
> + */
> + if (block->resized && unaligned_size !=
> memory_region_size(block->mr)) {
> + block->resized(block->idstr, unaligned_size, block->host);
> + memory_region_set_size(block->mr, unaligned_size);
> + }
I guess we should do
if (unaligned_size != memory_region_size(block->mr)) {
memory_region_set_size(block->mr, unaligned_size);
if (block->resized) {
block->resized(block->idstr, unaligned_size, block->host);
}
}
Instead - like in the case below.
Note: This is not completely clean, the RAM block code should'n have to
care about unaligned stuff. Also, the resized() callback for the RAM
block is ugly, it should be a resized callback for the memory region.
But these things imply requires bigger refactorings, so I guess this is
good and simple enough for now.
--
Thanks,
David / dhildenb
