[PATCH v2 4/6] x86/vmware: Add a bounded pre-kdump log sender

[sashiko-bot at kernel.org]

> Preserve the newest kernel log tail in the host's vmware.log, which can
> outlive a guest with no working userspace or persistent storage.
> 
> Allocate an 8 KiB buffer during early init and register on
> panic_pre_kdump_list. A 4 KiB buffer can omit useful stack-trace
> context. Use a fixed byte budget so transfer work does not scale
> with PAGE_SIZE.
> 
> Copy the newest records, prefix them with "log ", and send one RPC over
> the low-bandwidth register interface. Bound the transfer to 8 KiB and
> at most three checkpoint attempts; zero-fill a partial payload word and
> close the channel after every successful open.
> 
> The callback allocates nothing and emits no printk messages. Enable it
> for ordinary guests, leaving encrypted guests disabled until explicitly
> enabled by the sysctl. Skip initialization without printk support, and
> leave logging disabled after allocation or registration failure.
> 
> Suggested-by: Michael Kelley <mhklinux at outlook.com>
> Link: https://lore.kernel.org/r/SN6PR02MB41574A11D309A0530C63E0FED4842@SN6PR02MB4157.namprd02.prod.outlook.com
> Link: https://lore.kernel.org/r/20260309235250.2611115-3-alexey.makhalov@broadcom.com
> Co-developed-by: Bo Gan <bo.gan at broadcom.com>
> Signed-off-by: Bo Gan <bo.gan at broadcom.com>
> Co-developed-by: Alexey Makhalov <alexey.makhalov at broadcom.com>
> Signed-off-by: Alexey Makhalov <alexey.makhalov at broadcom.com>
> Signed-off-by: Zack Rusin <zack.rusin at broadcom.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1790014793.git.zack.rusin@broadcom.com?part=4