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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	David Brazdil <dbrazdil@google.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 10/19] KVM: arm64: Set CSV2 for guests on hardware unaffected by Spectre-v2
Date: Fri, 18 Sep 2020 17:47:20 +0100	[thread overview]
Message-ID: <20200918164729.31994-11-will@kernel.org> (raw)
In-Reply-To: <20200918164729.31994-1-will@kernel.org>

From: Marc Zyngier <maz@kernel.org>

If the system is not affected by Spectre-v2, then advertise to the KVM
guest that it is not affected, without the need for a safelist in the
guest.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 077293b5115f..7b8a8f6169d0 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1131,6 +1131,9 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
 		if (!vcpu_has_sve(vcpu))
 			val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
 		val &= ~(0xfUL << ID_AA64PFR0_AMU_SHIFT);
+		if (!(val & (0xfUL << ID_AA64PFR0_CSV2_SHIFT)) &&
+		    arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED)
+			val |= (1UL << ID_AA64PFR0_CSV2_SHIFT);
 	} else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) {
 		val &= ~((0xfUL << ID_AA64ISAR1_APA_SHIFT) |
 			 (0xfUL << ID_AA64ISAR1_API_SHIFT) |
-- 
2.28.0.681.g6f77f65b4e-goog


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  parent reply	other threads:[~2020-09-18 16:52 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-18 16:47 [PATCH 00/19] Fix and rewrite arm64 spectre mitigations Will Deacon
2020-09-18 16:47 ` [PATCH 01/19] arm64: Make use of ARCH_WORKAROUND_1 even when KVM is not enabled Will Deacon
2020-09-18 16:47   ` Will Deacon
2020-09-18 16:47 ` [PATCH 02/19] arm64: Run ARCH_WORKAROUND_1 enabling code on all CPUs Will Deacon
2020-09-18 16:47   ` Will Deacon
2020-09-21 12:54   ` Sasha Levin
2020-09-21 12:54     ` Sasha Levin
2020-09-18 16:47 ` [PATCH 03/19] arm64: Run ARCH_WORKAROUND_2 " Will Deacon
2020-09-18 16:47   ` Will Deacon
2020-09-18 17:13   ` Suzuki K Poulose
2020-09-18 17:13     ` Suzuki K Poulose
2020-09-18 16:47 ` [PATCH 04/19] arm64: Remove Spectre-related CONFIG_* options Will Deacon
2020-09-18 16:47 ` [PATCH 05/19] KVM: arm64: Replace CONFIG_KVM_INDIRECT_VECTORS with CONFIG_RANDOMIZE_BASE Will Deacon
2020-09-18 16:47 ` [PATCH 06/19] KVM: arm64: Simplify install_bp_hardening_cb() Will Deacon
2020-09-18 16:47 ` [PATCH 07/19] arm64: Rename ARM64_HARDEN_BRANCH_PREDICTOR to ARM64_SPECTRE_V2 Will Deacon
2020-09-18 16:47 ` [PATCH 08/19] arm64: Introduce separate file for spectre mitigations and reporting Will Deacon
2020-09-18 16:47 ` [PATCH 09/19] arm64: Rewrite Spectre-v2 mitigation code Will Deacon
2020-09-18 16:47 ` Will Deacon [this message]
2020-09-18 16:47 ` [PATCH 11/19] arm64: Group start_thread() functions together Will Deacon
2020-09-18 16:47 ` [PATCH 12/19] arm64: Treat SSBS as a non-strict system feature Will Deacon
2020-09-18 16:47 ` [PATCH 13/19] arm64: Rename ARM64_SSBD to ARM64_SPECTRE_V4 Will Deacon
2020-09-18 16:47 ` [PATCH 14/19] arm64: Move SSBD prctl() handler alongside other spectre mitigation code Will Deacon
2020-09-18 16:47 ` [PATCH 15/19] arm64: Rewrite Spectre-v4 " Will Deacon
2020-09-18 16:47 ` [PATCH 16/19] KVM: arm64: Simplify handling of ARCH_WORKAROUND_2 Will Deacon
2020-09-18 16:47 ` [PATCH 17/19] KVM: arm64: Get rid of kvm_arm_have_ssbd() Will Deacon
2020-09-18 16:47 ` [PATCH 18/19] KVM: arm64: Convert ARCH_WORKAROUND_2 to arm64_get_spectre_v4_state() Will Deacon
2020-09-18 16:47 ` [PATCH 19/19] arm64: Get rid of arm64_ssbd_state Will Deacon
2020-09-18 16:59 ` [PATCH 00/19] Fix and rewrite arm64 spectre mitigations Will Deacon

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