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)); +}