From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Thu, 30 Aug 2018 17:16:06 +0100 Subject: [PATCH 6/7] KVM: arm64: Set SCTLR_EL2.DSSBS if SSBD is forcefully disabled and !vhe In-Reply-To: <1535645767-9901-1-git-send-email-will.deacon@arm.com> References: <1535645767-9901-1-git-send-email-will.deacon@arm.com> Message-ID: <1535645767-9901-7-git-send-email-will.deacon@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org When running without VHE, it is necessary to set SCTLR_EL2.DSSBS if SSBD has been forcefully disabled on the kernel command-line. Signed-off-by: Will Deacon --- arch/arm64/include/asm/kvm_host.h | 11 +++++++++++ arch/arm64/kvm/hyp/sysreg-sr.c | 11 +++++++++++ 2 files changed, 22 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index f26055f2306e..15501921fc75 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -389,6 +389,8 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr); 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) @@ -409,6 +411,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr, */ 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) diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c index 9ce223944983..76d016b446b2 100644 --- a/arch/arm64/kvm/hyp/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/sysreg-sr.c @@ -288,3 +288,14 @@ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) 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)); +} -- 2.1.4