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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will.deacon@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	stable@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>
Subject: [PATCH 4.19 090/114] KVM: arm64: Set SCTLR_EL2.DSSBS if SSBD is forcefully disabled and !vhe
Date: Thu, 10 Oct 2019 10:36:37 +0200	[thread overview]
Message-ID: <20191010083612.834026878@linuxfoundation.org> (raw)
In-Reply-To: <20191010083544.711104709@linuxfoundation.org>

From: Will Deacon <will.deacon@arm.com>

[ Upstream commit 7c36447ae5a090729e7b129f24705bb231a07e0b ]

When running without VHE, it is necessary to set SCTLR_EL2.DSSBS if SSBD
has been forcefully disabled on the kernel command-line.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/include/asm/kvm_host.h |   11 +++++++++++
 arch/arm64/kvm/hyp/sysreg-sr.c    |   11 +++++++++++
 2 files changed, 22 insertions(+)

--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -398,6 +398,8 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struc
 
 DECLARE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
 
+void __kvm_enable_ssbs(void);
+
 static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 				       unsigned long hyp_stack_ptr,
 				       unsigned long vector_ptr)
@@ -418,6 +420,15 @@ static inline void __cpu_init_hyp_mode(p
 	 */
 	BUG_ON(!static_branch_likely(&arm64_const_caps_ready));
 	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr, tpidr_el2);
+
+	/*
+	 * Disabling SSBD on a non-VHE system requires us to enable SSBS
+	 * at EL2.
+	 */
+	if (!has_vhe() && this_cpu_has_cap(ARM64_SSBS) &&
+	    arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) {
+		kvm_call_hyp(__kvm_enable_ssbs);
+	}
 }
 
 static inline bool kvm_arch_check_sve_has_vhe(void)
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -293,3 +293,14 @@ void kvm_vcpu_put_sysregs(struct kvm_vcp
 
 	vcpu->arch.sysregs_loaded_on_cpu = false;
 }
+
+void __hyp_text __kvm_enable_ssbs(void)
+{
+	u64 tmp;
+
+	asm volatile(
+	"mrs	%0, sctlr_el2\n"
+	"orr	%0, %0, %1\n"
+	"msr	sctlr_el2, %0"
+	: "=&r" (tmp) : "L" (SCTLR_ELx_DSSBS));
+}



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  parent reply	other threads:[~2019-10-10  8:51 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191010083544.711104709@linuxfoundation.org>
2019-10-10  8:36 ` [PATCH 4.19 089/114] arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3 Greg Kroah-Hartman
2019-10-10  8:36 ` Greg Kroah-Hartman [this message]
2019-10-10  8:36 ` [PATCH 4.19 091/114] arm64: docs: Document SSBS HWCAP Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 092/114] arm64: fix SSBS sanitization Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 093/114] arm64: Add sysfs vulnerability show for spectre-v1 Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 094/114] arm64: add sysfs vulnerability show for meltdown Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 095/114] arm64: enable generic CPU vulnerabilites support Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 096/114] arm64: Always enable ssb vulnerability detection Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 097/114] arm64: Provide a command line to disable spectre_v2 mitigation Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 098/114] arm64: Advertise mitigation of Spectre-v2, or lack thereof Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 099/114] arm64: Always enable spectre-v2 vulnerability detection Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 100/114] arm64: add sysfs vulnerability show for spectre-v2 Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 101/114] arm64: add sysfs vulnerability show for speculative store bypass Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 102/114] arm64: ssbs: Dont treat CPUs with SSBS as unaffected by SSB Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 103/114] arm64: Force SSBS on context switch Greg Kroah-Hartman

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