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Message-ID: <20241105215455.359471-11-david.kaplan@amd.com>
Date: Tue, 5 Nov 2024 15:54:30 -0600
From: David Kaplan <david.kaplan@....com>
To: Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>,
Peter Zijlstra <peterz@...radead.org>, Josh Poimboeuf <jpoimboe@...nel.org>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, Ingo Molnar
<mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>,
<x86@...nel.org>, "H . Peter Anvin" <hpa@...or.com>
CC: <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 10/35] x86/bugs: Restructure gds mitigation
Restructure gds mitigation to use select/apply functions to create
consistent vulnerability handling.
Define new AUTO mitigation for gds.
Signed-off-by: David Kaplan <david.kaplan@....com>
---
arch/x86/kernel/cpu/bugs.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 452aa5994aac..37056bdd3a9b 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -76,6 +76,7 @@ static void __init srbds_apply_mitigation(void);
static void __init l1d_flush_select_mitigation(void);
static void __init srso_select_mitigation(void);
static void __init gds_select_mitigation(void);
+static void __init gds_apply_mitigation(void);
/* The base value of the SPEC_CTRL MSR without task-specific bits set */
u64 x86_spec_ctrl_base;
@@ -220,6 +221,7 @@ void __init cpu_select_mitigations(void)
mmio_apply_mitigation();
rfds_apply_mitigation();
srbds_apply_mitigation();
+ gds_apply_mitigation();
}
/*
@@ -801,6 +803,7 @@ early_param("l1d_flush", l1d_flush_parse_cmdline);
enum gds_mitigations {
GDS_MITIGATION_OFF,
+ GDS_MITIGATION_AUTO,
GDS_MITIGATION_UCODE_NEEDED,
GDS_MITIGATION_FORCE,
GDS_MITIGATION_FULL,
@@ -809,7 +812,7 @@ enum gds_mitigations {
};
static enum gds_mitigations gds_mitigation __ro_after_init =
- IS_ENABLED(CONFIG_MITIGATION_GDS) ? GDS_MITIGATION_FULL : GDS_MITIGATION_OFF;
+ IS_ENABLED(CONFIG_MITIGATION_GDS) ? GDS_MITIGATION_AUTO : GDS_MITIGATION_OFF;
static const char * const gds_strings[] = {
[GDS_MITIGATION_OFF] = "Vulnerable",
@@ -850,6 +853,7 @@ void update_gds_msr(void)
case GDS_MITIGATION_FORCE:
case GDS_MITIGATION_UCODE_NEEDED:
case GDS_MITIGATION_HYPERVISOR:
+ case GDS_MITIGATION_AUTO:
return;
}
@@ -873,13 +877,16 @@ static void __init gds_select_mitigation(void)
if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
gds_mitigation = GDS_MITIGATION_HYPERVISOR;
- goto out;
+ return;
}
if (cpu_mitigations_off())
gds_mitigation = GDS_MITIGATION_OFF;
/* Will verify below that mitigation _can_ be disabled */
+ if (gds_mitigation == GDS_MITIGATION_AUTO)
+ gds_mitigation = GDS_MITIGATION_FULL;
+
/* No microcode */
if (!(x86_arch_cap_msr & ARCH_CAP_GDS_CTRL)) {
if (gds_mitigation == GDS_MITIGATION_FORCE) {
@@ -892,7 +899,7 @@ static void __init gds_select_mitigation(void)
} else {
gds_mitigation = GDS_MITIGATION_UCODE_NEEDED;
}
- goto out;
+ return;
}
/* Microcode has mitigation, use it */
@@ -914,8 +921,14 @@ static void __init gds_select_mitigation(void)
gds_mitigation = GDS_MITIGATION_FULL_LOCKED;
}
+}
+
+static void __init gds_apply_mitigation(void)
+{
+ if (!boot_cpu_has_bug(X86_BUG_GDS))
+ return;
+
update_gds_msr();
-out:
pr_info("%s\n", gds_strings[gds_mitigation]);
}
--
2.34.1
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