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Re: [PATCH v3 03/10] exec: Fix for qemu_ram_resize() callback
From: |
David Hildenbrand |
Subject: |
Re: [PATCH v3 03/10] exec: Fix for qemu_ram_resize() callback |
Date: |
Wed, 11 Mar 2020 18:44:59 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 |
On 11.03.20 18:20, Shameer Kolothum wrote:
> From: David Hildenbrand <address@hidden>
>
> 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 <address@hidden>
> [Shameer: added commit log]
> Signed-off-by: Shameer Kolothum <address@hidden>
> ---
> 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
- RE: [PATCH v3 02/10] fw_cfg: Migrate ACPI table mr sizes separately, (continued)
Re: [PATCH v3 02/10] fw_cfg: Migrate ACPI table mr sizes separately, Igor Mammedov, 2020/03/23
[PATCH v3 01/10] acpi: Use macro for table-loader file name, Shameer Kolothum, 2020/03/11
[PATCH v3 04/10] hw/acpi/nvdimm: Fix for NVDIMM incorrect DSM output buffer length, Shameer Kolothum, 2020/03/11
[PATCH v3 03/10] exec: Fix for qemu_ram_resize() callback, Shameer Kolothum, 2020/03/11
[PATCH v3 05/10] nvdimm: Use configurable ACPI IO base and size, Shameer Kolothum, 2020/03/11
[PATCH v3 06/10] hw/arm/virt: Add nvdimm hot-plug infrastructure, Shameer Kolothum, 2020/03/11
[PATCH v3 08/10] tests: Update ACPI tables list for upcoming arm/virt test changes, Shameer Kolothum, 2020/03/11
[PATCH v3 07/10] hw/arm/virt: Add nvdimm hotplug support, Shameer Kolothum, 2020/03/11
[PATCH v3 09/10] tests/bios-tables-test: Update arm/virt memhp test, Shameer Kolothum, 2020/03/11