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From: Will Deacon <will@kernel.org>
To: kvmarm@lists.cs.columbia.edu
Cc: catalin.marinas@arm.com, kernel-team@android.com,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>
Subject: [PATCH v3 10/10] KVM: arm64: Remove redundant hyp vectors entry
Date: Fri, 13 Nov 2020 11:38:47 +0000	[thread overview]
Message-ID: <20201113113847.21619-11-will@kernel.org> (raw)
In-Reply-To: <20201113113847.21619-1-will@kernel.org>

The hyp vectors entry corresponding to HYP_VECTOR_DIRECT (i.e. when
neither Spectre-v2 nor Spectre-v3a are present) is unused, as we can
simply dispatch straight to __kvm_hyp_vector in this case.

Remove the redundant vector, and massage the logic for resolving a slot
to a vectors entry.

Reported-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/include/asm/spectre.h | 2 +-
 arch/arm64/kvm/arm.c             | 9 ++++++++-
 arch/arm64/kvm/hyp/hyp-entry.S   | 1 -
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h
index 12a4eb5e4e6b..4e6d90a4fbe0 100644
--- a/arch/arm64/include/asm/spectre.h
+++ b/arch/arm64/include/asm/spectre.h
@@ -10,7 +10,7 @@
 #define __ASM_SPECTRE_H
 
 #define BP_HARDEN_EL2_SLOTS 4
-#define __BP_HARDEN_HYP_VECS_SZ (BP_HARDEN_EL2_SLOTS * SZ_2K)
+#define __BP_HARDEN_HYP_VECS_SZ	((BP_HARDEN_EL2_SLOTS - 1) * SZ_2K)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index d94b12376d62..ef2c9433fadd 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1298,9 +1298,16 @@ static unsigned long nvhe_percpu_order(void)
 /* A lookup table holding the hypervisor VA for each vector slot */
 static void *hyp_spectre_vector_selector[BP_HARDEN_EL2_SLOTS];
 
+static int __kvm_vector_slot2idx(enum arm64_hyp_spectre_vector slot)
+{
+	return slot - (slot != HYP_VECTOR_DIRECT);
+}
+
 static void kvm_init_vector_slot(void *base, enum arm64_hyp_spectre_vector slot)
 {
-	hyp_spectre_vector_selector[slot] = base + (slot * SZ_2K);
+	int idx = __kvm_vector_slot2idx(slot);
+
+	hyp_spectre_vector_selector[slot] = base + (idx * SZ_2K);
 }
 
 static int kvm_init_vector_slots(void)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index e3249e2dda09..d179056e1af8 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -239,7 +239,6 @@ SYM_CODE_END(__kvm_hyp_vector)
 
 	.align	11
 SYM_CODE_START(__bp_harden_hyp_vecs)
-	generate_vectors indirect = 0, spectrev2 = 0 // HYP_VECTOR_DIRECT
 	generate_vectors indirect = 0, spectrev2 = 1 // HYP_VECTOR_SPECTRE_DIRECT
 	generate_vectors indirect = 1, spectrev2 = 0 // HYP_VECTOR_INDIRECT
 	generate_vectors indirect = 1, spectrev2 = 1 // HYP_VECTOR_SPECTRE_INDIRECT
-- 
2.29.2.299.gdc1121823c-goog

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      parent reply	other threads:[~2020-11-13 11:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-13 11:38 [PATCH v3 00/10] Rework hyp vector handling Will Deacon
2020-11-13 11:38 ` [PATCH v3 01/10] KVM: arm64: Remove redundant Spectre-v2 code from kvm_map_vector() Will Deacon
2020-11-13 11:38 ` [PATCH v3 02/10] KVM: arm64: Tidy up kvm_map_vector() Will Deacon
2020-11-13 11:38 ` [PATCH v3 03/10] KVM: arm64: Move kvm_get_hyp_vector() out of header file Will Deacon
2020-11-13 11:38 ` [PATCH v3 04/10] KVM: arm64: Make BP hardening globals static instead Will Deacon
2020-11-13 11:38 ` [PATCH v3 05/10] KVM: arm64: Move BP hardening helpers into spectre.h Will Deacon
2020-11-13 11:38 ` [PATCH v3 06/10] KVM: arm64: Re-jig logic when patching hardened hyp vectors Will Deacon
2020-11-13 11:38 ` [PATCH v3 07/10] KVM: arm64: Allocate hyp vectors statically Will Deacon
2020-11-13 12:02   ` Marc Zyngier
2020-11-13 12:10     ` Will Deacon
2020-11-13 11:38 ` [PATCH v3 08/10] arm64: spectre: Rename ARM64_HARDEN_EL2_VECTORS to ARM64_SPECTRE_V3A Will Deacon
2020-11-13 11:38 ` [PATCH v3 09/10] arm64: spectre: Consolidate spectre-v3a detection Will Deacon
2020-11-13 11:38 ` Will Deacon [this message]

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