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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: kernel-team@android.com, Will Deacon <will@kernel.org>
Subject: [PATCH 1/2] arm64: Make the Meltdown mitigation state available
Date: Sat, 28 Nov 2020 12:46:58 +0000	[thread overview]
Message-ID: <20201128124659.669578-2-maz@kernel.org> (raw)
In-Reply-To: <20201128124659.669578-1-maz@kernel.org>

Our Meltdown mitigation state isn't exposed outside of cpufeature.c,
contrary to the rest of the Spectre mitigation state. As we are going
to use it in KVM, expose a arm64_get_meltdown_state() helper which
returns the same possible values as arm64_get_spectre_v?_state().

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/spectre.h |  2 ++
 arch/arm64/kernel/cpufeature.c   | 20 +++++++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h
index fcdfbce302bd..52e788981f4a 100644
--- a/arch/arm64/include/asm/spectre.h
+++ b/arch/arm64/include/asm/spectre.h
@@ -29,4 +29,6 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope);
 void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 void spectre_v4_enable_task_mitigation(struct task_struct *tsk);
 
+enum mitigation_state arm64_get_meltdown_state(void);
+
 #endif	/* __ASM_SPECTRE_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6f36c4f62f69..280b10762f6b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2846,14 +2846,28 @@ static int __init enable_mrs_emulation(void)
 
 core_initcall(enable_mrs_emulation);
 
+enum mitigation_state arm64_get_meltdown_state(void)
+{
+	if (__meltdown_safe)
+		return SPECTRE_UNAFFECTED;
+
+	if (arm64_kernel_unmapped_at_el0())
+		return SPECTRE_MITIGATED;
+
+	return SPECTRE_VULNERABLE;
+}
+
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
-	if (__meltdown_safe)
+	switch (arm64_get_meltdown_state()) {
+	case SPECTRE_UNAFFECTED:
 		return sprintf(buf, "Not affected\n");
 
-	if (arm64_kernel_unmapped_at_el0())
+	case SPECTRE_MITIGATED:
 		return sprintf(buf, "Mitigation: PTI\n");
 
-	return sprintf(buf, "Vulnerable\n");
+	default:
+		return sprintf(buf, "Vulnerable\n");
+	}
 }
-- 
2.28.0

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: James Morse <james.morse@arm.com>,
	kernel-team@android.com, Will Deacon <will@kernel.org>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 1/2] arm64: Make the Meltdown mitigation state available
Date: Sat, 28 Nov 2020 12:46:58 +0000	[thread overview]
Message-ID: <20201128124659.669578-2-maz@kernel.org> (raw)
In-Reply-To: <20201128124659.669578-1-maz@kernel.org>

Our Meltdown mitigation state isn't exposed outside of cpufeature.c,
contrary to the rest of the Spectre mitigation state. As we are going
to use it in KVM, expose a arm64_get_meltdown_state() helper which
returns the same possible values as arm64_get_spectre_v?_state().

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/spectre.h |  2 ++
 arch/arm64/kernel/cpufeature.c   | 20 +++++++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h
index fcdfbce302bd..52e788981f4a 100644
--- a/arch/arm64/include/asm/spectre.h
+++ b/arch/arm64/include/asm/spectre.h
@@ -29,4 +29,6 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope);
 void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 void spectre_v4_enable_task_mitigation(struct task_struct *tsk);
 
+enum mitigation_state arm64_get_meltdown_state(void);
+
 #endif	/* __ASM_SPECTRE_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6f36c4f62f69..280b10762f6b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2846,14 +2846,28 @@ static int __init enable_mrs_emulation(void)
 
 core_initcall(enable_mrs_emulation);
 
+enum mitigation_state arm64_get_meltdown_state(void)
+{
+	if (__meltdown_safe)
+		return SPECTRE_UNAFFECTED;
+
+	if (arm64_kernel_unmapped_at_el0())
+		return SPECTRE_MITIGATED;
+
+	return SPECTRE_VULNERABLE;
+}
+
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
-	if (__meltdown_safe)
+	switch (arm64_get_meltdown_state()) {
+	case SPECTRE_UNAFFECTED:
 		return sprintf(buf, "Not affected\n");
 
-	if (arm64_kernel_unmapped_at_el0())
+	case SPECTRE_MITIGATED:
 		return sprintf(buf, "Mitigation: PTI\n");
 
-	return sprintf(buf, "Vulnerable\n");
+	default:
+		return sprintf(buf, "Vulnerable\n");
+	}
 }
-- 
2.28.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Will Deacon <will@kernel.org>, James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	kernel-team@android.com
Subject: [PATCH 1/2] arm64: Make the Meltdown mitigation state available
Date: Sat, 28 Nov 2020 12:46:58 +0000	[thread overview]
Message-ID: <20201128124659.669578-2-maz@kernel.org> (raw)
In-Reply-To: <20201128124659.669578-1-maz@kernel.org>

Our Meltdown mitigation state isn't exposed outside of cpufeature.c,
contrary to the rest of the Spectre mitigation state. As we are going
to use it in KVM, expose a arm64_get_meltdown_state() helper which
returns the same possible values as arm64_get_spectre_v?_state().

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/spectre.h |  2 ++
 arch/arm64/kernel/cpufeature.c   | 20 +++++++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h
index fcdfbce302bd..52e788981f4a 100644
--- a/arch/arm64/include/asm/spectre.h
+++ b/arch/arm64/include/asm/spectre.h
@@ -29,4 +29,6 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope);
 void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 void spectre_v4_enable_task_mitigation(struct task_struct *tsk);
 
+enum mitigation_state arm64_get_meltdown_state(void);
+
 #endif	/* __ASM_SPECTRE_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6f36c4f62f69..280b10762f6b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2846,14 +2846,28 @@ static int __init enable_mrs_emulation(void)
 
 core_initcall(enable_mrs_emulation);
 
+enum mitigation_state arm64_get_meltdown_state(void)
+{
+	if (__meltdown_safe)
+		return SPECTRE_UNAFFECTED;
+
+	if (arm64_kernel_unmapped_at_el0())
+		return SPECTRE_MITIGATED;
+
+	return SPECTRE_VULNERABLE;
+}
+
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
-	if (__meltdown_safe)
+	switch (arm64_get_meltdown_state()) {
+	case SPECTRE_UNAFFECTED:
 		return sprintf(buf, "Not affected\n");
 
-	if (arm64_kernel_unmapped_at_el0())
+	case SPECTRE_MITIGATED:
 		return sprintf(buf, "Mitigation: PTI\n");
 
-	return sprintf(buf, "Vulnerable\n");
+	default:
+		return sprintf(buf, "Vulnerable\n");
+	}
 }
-- 
2.28.0


  reply	other threads:[~2020-11-28 12:47 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-28 12:46 [PATCH 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW Marc Zyngier
2020-11-28 12:46 ` Marc Zyngier
2020-11-28 12:46 ` Marc Zyngier
2020-11-28 12:46 ` Marc Zyngier [this message]
2020-11-28 12:46   ` [PATCH 1/2] arm64: Make the Meltdown mitigation state available Marc Zyngier
2020-11-28 12:46   ` Marc Zyngier
2020-11-28 12:46 ` [PATCH 2/2] KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are Meltdown-safe Marc Zyngier
2020-11-28 12:46   ` Marc Zyngier
2020-11-28 12:46   ` Marc Zyngier
2020-11-30 15:26   ` David Brazdil
2020-11-30 15:26     ` David Brazdil
2020-11-30 15:26     ` David Brazdil
2020-11-30 15:40     ` Marc Zyngier
2020-11-30 15:40       ` Marc Zyngier
2020-11-30 15:40       ` Marc Zyngier

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