On Wed, Dec 11, 2024 at 09:08:43PM +0800, Baoquan He wrote:
On 10/29/24 at 01:52pm, Coiby Xu wrote:When there are CPU and memory hot un/plugs, the dm crypt keys may need to be reloaded again depending on the solution for crash hotplug support. Currently, there are two solutions. One is to utilizes udev to instruct user space to reload the kdump kernel image and initrd, elfcorehdr and etc again. The other is to only update the elfcorehdr segment introduced in commit 247262756121 ("crash: add generic infrastructure for crash hotplug support"). For the 1st solution, the dm crypt keys need to be reloaded again. The user space can write true to /sys/kernel/config/crash_dm_crypt_key/reuse so the stored keys can be re-used. For the 2nd solution, the dm crypt keys don't need to be reloaded. Currently, only x86 supports the 2nd solution. If the 2nd solution gets extended to all arches, this patch can be dropped. Signed-off-by: Coiby Xu <coxu@xxxxxxxxxx> --- kernel/crash_dump_dm_crypt.c | 52 +++++++++++++++++++++++++++++++++--- 1 file changed, 48 insertions(+), 4 deletions(-) diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c index ec2ec2967242..51431f93fc1e 100644 --- a/kernel/crash_dump_dm_crypt.c +++ b/kernel/crash_dump_dm_crypt.c @@ -28,6 +28,20 @@ static size_t get_keys_header_size(size_t total_keys) return struct_size(keys_header, keys, total_keys); } +static void get_keys_from_kdump_reserved_memory(void) +{ + struct keys_header *keys_header_loaded; + + arch_kexec_unprotect_crashkres(); + + keys_header_loaded = kmap_local_page(pfn_to_page( + kexec_crash_image->dm_crypt_keys_addr >> PAGE_SHIFT)); + + memcpy(keys_header, keys_header_loaded, get_keys_header_size(key_count)); + kunmap_local(keys_header_loaded); + arch_kexec_protect_crashkres(); +} + static int read_key_from_user_keying(struct dm_crypt_key *dm_key) { const struct user_key_payload *ukp; @@ -150,8 +164,36 @@ static ssize_t config_keys_count_show(struct config_item *item, char *page) CONFIGFS_ATTR_RO(config_keys_, count); +static bool reuse;Give it a meaningful name since it's a global variable, e.g is_dm_key_reused?
Sure, I'll use is_dm_key_reused in next version! Thanks for the suggestion to improve code readability! -- Best regards, Coiby
