From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: x86@kernel.org
Cc: David Kaplan <david.kaplan@amd.com>,
linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Nikolay Borisov <nik.borisov@suse.com>
Subject: [PATCH v3 2/7] x86/retbleed: Simplify the =stuff checks
Date: Thu, 22 May 2025 18:20:47 -0700 [thread overview]
Message-ID: <20250522-eibrs-fix-v3-2-12704e291e1e@linux.intel.com> (raw)
In-Reply-To: <20250522-eibrs-fix-v3-0-12704e291e1e@linux.intel.com>
Simplify the nested checks, remove redundant print and comment.
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
---
arch/x86/kernel/cpu/bugs.c | 24 ++++++++----------------
1 file changed, 8 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 53649df2c4d66c6bd3aa34dec69af9df253bccfc..94d0de3e61aec32b3b67c8d21f89a8c67b93dff3 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1263,24 +1263,16 @@ static void __init retbleed_update_mitigation(void)
if (!boot_cpu_has_bug(X86_BUG_RETBLEED) || cpu_mitigations_off())
return;
- /*
- * retbleed=stuff is only allowed on Intel. If stuffing can't be used
- * then a different mitigation will be selected below.
- *
- * its=stuff will also attempt to enable stuffing.
- */
- if (retbleed_mitigation == RETBLEED_MITIGATION_STUFF ||
- its_mitigation == ITS_MITIGATION_RETPOLINE_STUFF) {
- if (spectre_v2_enabled != SPECTRE_V2_RETPOLINE) {
- pr_err("WARNING: retbleed=stuff depends on spectre_v2=retpoline\n");
- retbleed_mitigation = RETBLEED_MITIGATION_NONE;
- } else {
- if (retbleed_mitigation != RETBLEED_MITIGATION_STUFF)
- pr_info("Retbleed mitigation updated to stuffing\n");
+ /* ITS can also enable stuffing */
+ if (its_mitigation == ITS_MITIGATION_RETPOLINE_STUFF)
+ retbleed_mitigation = RETBLEED_MITIGATION_STUFF;
- retbleed_mitigation = RETBLEED_MITIGATION_STUFF;
- }
+ if (retbleed_mitigation == RETBLEED_MITIGATION_STUFF &&
+ spectre_v2_enabled != SPECTRE_V2_RETPOLINE) {
+ pr_err("WARNING: retbleed=stuff depends on spectre_v2=retpoline\n");
+ retbleed_mitigation = RETBLEED_MITIGATION_NONE;
}
+
/*
* Let IBRS trump all on Intel without affecting the effects of the
* retbleed= cmdline option except for call depth based stuffing
--
2.34.1
next prev parent reply other threads:[~2025-05-23 1:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-23 1:20 [PATCH v3 0/7] eIBRS fixes Pawan Gupta
2025-05-23 1:20 ` [PATCH v3 1/7] x86/retbleed: Avoid AUTO after the select step Pawan Gupta
2025-05-24 9:29 ` Borislav Petkov
2025-05-23 1:20 ` Pawan Gupta [this message]
2025-05-24 11:16 ` [PATCH v3 2/7] x86/retbleed: Simplify the =stuff checks Borislav Petkov
2025-05-23 1:21 ` [PATCH v3 3/7] x86/bugs: Exit early if return thunk is already set Pawan Gupta
2025-05-23 10:28 ` Nikolay Borisov
2025-05-24 11:27 ` Borislav Petkov
2025-05-28 21:55 ` Pawan Gupta
2025-05-23 1:21 ` [PATCH v3 4/7] x86/its: Use switch/case to apply mitigation Pawan Gupta
2025-05-23 1:21 ` [PATCH v3 5/7] x86/retbleed: Introduce cdt_possible() Pawan Gupta
2025-05-23 1:21 ` [PATCH v3 6/7] x86/its: Remove =stuff dependency on retbleed Pawan Gupta
2025-05-23 1:22 ` [PATCH v3 7/7] x86/its: Allow stuffing in eIBRS+retpoline mode also Pawan Gupta
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