From: James Morse james.morse@arm.com
commit 5bdf3437603d4af87f9c7f424b0c8aeed2420745 upstream.
CPUs vulnerable to Spectre-BHB either need to make an SMC-CC firmware call from the vectors, or run a sequence of branches. This gets added to the hyp vectors. If there is no support for arch-workaround-1 in firmware, the indirect vector will be used.
kvm_init_vector_slots() only initialises the two indirect slots if the platform is vulnerable to Spectre-v3a. pKVM's hyp_map_vectors() only initialises __hyp_bp_vect_base if the platform is vulnerable to Spectre-v3a.
As there are about to more users of the indirect vectors, ensure their entries in hyp_spectre_vector_selector[] are always initialised, and __hyp_bp_vect_base defaults to the regular VA mapping.
The Spectre-v3a check is moved to a helper kvm_system_needs_idmapped_vectors(), and merged with the code that creates the hyp mappings.
Reviewed-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/include/asm/kvm_host.h | 5 +++++ arch/arm64/kvm/arm.c | 5 +---- arch/arm64/kvm/hyp/nvhe/mm.c | 4 +++- 3 files changed, 9 insertions(+), 5 deletions(-)
--- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -711,6 +711,11 @@ static inline void kvm_init_host_cpu_con ctxt_sys_reg(cpu_ctxt, MPIDR_EL1) = read_cpuid_mpidr(); }
+static inline bool kvm_system_needs_idmapped_vectors(void) +{ + return cpus_have_const_cap(ARM64_SPECTRE_V3A); +} + void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu);
static inline void kvm_arch_hardware_unsetup(void) {} --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1458,10 +1458,7 @@ static int kvm_init_vector_slots(void) base = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs)); kvm_init_vector_slot(base, HYP_VECTOR_SPECTRE_DIRECT);
- if (!cpus_have_const_cap(ARM64_SPECTRE_V3A)) - return 0; - - if (!has_vhe()) { + if (kvm_system_needs_idmapped_vectors() && !has_vhe()) { err = create_hyp_exec_mappings(__pa_symbol(__bp_harden_hyp_vecs), __BP_HARDEN_HYP_VECS_SZ, &base); if (err) --- a/arch/arm64/kvm/hyp/nvhe/mm.c +++ b/arch/arm64/kvm/hyp/nvhe/mm.c @@ -146,8 +146,10 @@ int hyp_map_vectors(void) phys_addr_t phys; void *bp_base;
- if (!cpus_have_const_cap(ARM64_SPECTRE_V3A)) + if (!kvm_system_needs_idmapped_vectors()) { + __hyp_bp_vect_base = __bp_harden_hyp_vecs; return 0; + }
phys = __hyp_pa(__bp_harden_hyp_vecs); bp_base = (void *)__pkvm_create_private_mapping(phys,