Hi Baoquan,
On Thu, 21 Sep 2023 18:01:02 +0800 Baoquan He bhe@redhat.com wrote:
It's reported that kdump kernel failed to boot and can't dump vmcore when crashkernel=192M and SME/SEV is active.
This is because swiotlb will be enabled and reserves 64M memory by default on system with SME/SEV enabled. Then kdump kernel will be out of memory after taking 64M away for swiotlb init.
So here add extra 64M memory to default crashkernel value so that kdump kernel can function well as before. When doing that, search journalctl for the "Memory Encryption Features active: AMD" to check if SME or SEV is active. This line of log is printed out in kernel function as below and the type SME is mutual exclusive with type SEV. ***: arch/x86/mm/mem_encrypt.c:print_mem_encrypt_feature_info()
Note:
The conditional check is relying on journalctl log because I didn't find available system interface to check if SEV is active. Even though we can check if SME is active via /proc/cpuinfo. For consistency, I take the same check for both SME and SEV by searching journalctl.
The conditional check is relying on journalctl log, means it won't work for crashkernel setting in anoconda because the installation kernel doesn't have the SME/SEV setting. So customer need manually run 'kdumpctl reset-crashkernel' to reset crashkernel to add the extra 64M after OS installation.
We need watch the line of log printing in print_mem_encrypt_feature_info() in kernel just in case people may change it in the future.
Signed-off-by: Baoquan He bhe@redhat.com
v2->v3:
- Redirect the stdin|out to /dev/null since "journalctl -q" can't suppress output completely. Suggested by Coiby.
- Define local variable "_delta" to contain the value added on "$_ck_cmdline". This is suggested by Philipp.
kdump-lib.sh | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kdump-lib.sh b/kdump-lib.sh index 16238c508f65..89b6d39506fb 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -38,6 +38,11 @@ is_aws_aarch64() [[ "$(lscpu | grep "BIOS Model name")" =~ "AWS Graviton" ]] }
+is_sme_or_sev_active() +{
- journalctl -q --dmesg --grep "^Memory Encryption Features active: AMD (SME|SEV)$" >/dev/null 2>&1
You can use '&>' as short hand to redirect both stdout and stderr, i.e. s;>/dev/null 2>&1;&>/dev/null;
Anyway, that's just a very minor code cleanup and you don't need to include it.
Reviewed-by: Philipp Rudo prudo@redhat.com
+}
is_squash_available() { local _version kmodule @@ -917,6 +922,7 @@ _crashkernel_add() kdump_get_arch_recommend_crashkernel() { local _arch _ck_cmdline _dump_mode
local _delta=0
if [[ -z "$1" ]]; then if is_fadump_capable; then
@@ -932,9 +938,9 @@ kdump_get_arch_recommend_crashkernel()
if [[ $_arch == "x86_64" ]] || [[ $_arch == "s390x" ]]; then _ck_cmdline="1G-4G:192M,4G-64G:256M,64G-:512M"
elif [[ $_arch == "aarch64" ]]; then local _running_kernelis_sme_or_sev_active && ((_delta += 64))
local _delta=0
# Base line for 4K variant kernel. The formula is based on x86 plus extra = 64M _ck_cmdline="1G-4G:256M,4G-64G:320M,64G-:576M"
@@ -958,7 +964,6 @@ kdump_get_arch_recommend_crashkernel() #4k kernel, mlx5 consumes extra 124M memory, and choose 150M has_mlx5 && ((_delta += 150)) fi
elif [[ $_arch == "ppc64le" ]]; then if [[ $_dump_mode == "fadump" ]]; then _ck_cmdline="4G-16G:768M,16G-64G:1G,64G-128G:2G,128G-1T:4G,1T-2T:6G,2T-4T:12G,4T-8T:20G,8T-16T:36G,16T-32T:64G,32T-64T:128G,64T-:180G"_ck_cmdline=$(_crashkernel_add "$_ck_cmdline" "$_delta")
@@ -967,7 +972,7 @@ kdump_get_arch_recommend_crashkernel() fi fi
- echo -n "$_ck_cmdline"
- echo -n "$(_crashkernel_add "$_ck_cmdline" "$_delta")"
}
# return recommended size based on current system RAM size