[ Sasha's backport helper bot ]
Hi,
Summary of potential issues:
ℹ️ Patch is missing in 6.6.y (ignore if backport was sent)
ℹ️ Patch is missing in 6.1.y (ignore if backport was sent)
ℹ️ Patch is missing in 5.15.y (ignore if backport was sent)
ℹ️ Patch is missing in 5.4.y (ignore if backport was sent)
The upstream commit SHA1 provided is correct: 318e8c339c9a0891c389298bb328ed0762a9935e
Status in newer kernel trees:
6.13.y | Present (different SHA1: 0bdda736ef7f)
6.12.y | Present (different SHA1: eea6d16f56e9)
6.6.y | Not found
6.1.y | Not found
5.15.y | Not found
5.4.y | Not found
Note: The patch differs from the upstream commit:
---
1: 318e8c339c9a0 ! 1: 8b887b2a63b14 x86/cpu/kvm: SRSO: Fix possible missing IBPB on VM-Exit
@@ Metadata
## Commit message ##
x86/cpu/kvm: SRSO: Fix possible missing IBPB on VM-Exit
+ commit 318e8c339c9a0891c389298bb328ed0762a9935e upstream.
+
In [1] the meaning of the synthetic IBPB flags has been redefined for a
better separation of concerns:
- ENTRY_IBPB -- issue IBPB on entry only
@@ Commit message
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
## arch/x86/Kconfig ##
-@@ arch/x86/Kconfig: config MITIGATION_IBPB_ENTRY
+@@ arch/x86/Kconfig: config CPU_IBPB_ENTRY
depends on CPU_SUP_AMD && X86_64
default y
help
@@ arch/x86/Kconfig: config MITIGATION_IBPB_ENTRY
+ Compile the kernel with support for the retbleed=ibpb and
+ spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
- config MITIGATION_IBRS_ENTRY
+ config CPU_IBRS_ENTRY
bool "Enable IBRS on kernel entry"
## arch/x86/kernel/cpu/bugs.c ##
@@ arch/x86/kernel/cpu/bugs.c: static void __init retbleed_select_mitigation(void)
setup_clear_cpu_cap(X86_FEATURE_UNRET);
setup_clear_cpu_cap(X86_FEATURE_RETHUNK);
-- setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT);
- mitigate_smt = true;
-
/*
* There is no need for RSB filling: entry_ibpb() ensures
* all predictions, including the RSB, are invalidated,
@@ arch/x86/kernel/cpu/bugs.c: static void __init srso_select_mitigation(void)
- if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY)) {
+ if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) {
if (has_microcode) {
setup_force_cpu_cap(X86_FEATURE_ENTRY_IBPB);
+ setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT);
@@ arch/x86/kernel/cpu/bugs.c: static void __init srso_select_mitigation(void)
+ setup_clear_cpu_cap(X86_FEATURE_RSB_VMEXIT);
}
} else {
- pr_err("WARNING: kernel not compiled with MITIGATION_IBPB_ENTRY.\n");
+ pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n");
@@ arch/x86/kernel/cpu/bugs.c: static void __init srso_select_mitigation(void)
+ break;
- ibpb_on_vmexit:
case SRSO_CMD_IBPB_ON_VMEXIT:
-- if (IS_ENABLED(CONFIG_MITIGATION_SRSO)) {
+- if (IS_ENABLED(CONFIG_CPU_SRSO)) {
- if (!boot_cpu_has(X86_FEATURE_ENTRY_IBPB) && has_microcode) {
-+ if (IS_ENABLED(CONFIG_MITIGATION_IBPB_ENTRY)) {
++ if (IS_ENABLED(CONFIG_CPU_IBPB_ENTRY)) {
+ if (has_microcode) {
setup_force_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT);
srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT;
@@ arch/x86/kernel/cpu/bugs.c: static void __init srso_select_mitigation(void)
setup_clear_cpu_cap(X86_FEATURE_RSB_VMEXIT);
}
} else {
-- pr_err("WARNING: kernel not compiled with MITIGATION_SRSO.\n");
+- pr_err("WARNING: kernel not compiled with CPU_SRSO.\n");
++ pr_err("WARNING: kernel not compiled with CPU_IBPB_ENTRY.\n");
+ goto pred_cmd;
- }
-+ pr_err("WARNING: kernel not compiled with MITIGATION_IBPB_ENTRY.\n");
+ }
break;
+
default:
- break;
---
Results of testing on various branches:
| Branch | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.10.y | Success | Success |
