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UPSTREAM: KVM: arm64: Allow indirect vectors to be used without SPECTRE_V3A

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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.

Bug: 215557547
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
(cherry picked from commit 5bdf343760)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6ad747d012e2d9965a9450e62bebd5bfe1605316
This commit is contained in:
James Morse 2021-11-16 15:06:19 +00:00 committed by Greg Kroah-Hartman
parent fee1ae7c7c
commit e9a39a642c
3 changed files with 9 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/arm64/include/asm/kvm_host.h
View File

@ -705,6 +705,11 @@ static inline void kvm_init_host_cpu_context(struct kvm_cpu_context *cpu_ctxt)
ctxt_sys_reg(cpu_ctxt, MPIDR_EL1) = read_cpuid_mpidr(); 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); void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu);
static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_hardware_unsetup(void) {}

5
arch/arm64/kvm/arm.c
View File

@ -1388,10 +1388,7 @@ static int kvm_init_vector_slots(void)
base = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs)); base = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs));
kvm_init_vector_slot(base, HYP_VECTOR_SPECTRE_DIRECT); kvm_init_vector_slot(base, HYP_VECTOR_SPECTRE_DIRECT);
if (!cpus_have_const_cap(ARM64_SPECTRE_V3A)) if (kvm_system_needs_idmapped_vectors() && !has_vhe()) {
return 0;
if (!has_vhe()) {
err = create_hyp_exec_mappings(__pa_symbol(__bp_harden_hyp_vecs), err = create_hyp_exec_mappings(__pa_symbol(__bp_harden_hyp_vecs),
__BP_HARDEN_HYP_VECS_SZ, &base); __BP_HARDEN_HYP_VECS_SZ, &base);
if (err) if (err)

4
arch/arm64/kvm/hyp/nvhe/mm.c
View File

@ -132,8 +132,10 @@ int hyp_map_vectors(void)
phys_addr_t phys; phys_addr_t phys;
void *bp_base; 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; return 0;
}
phys = __hyp_pa(__bp_harden_hyp_vecs); phys = __hyp_pa(__bp_harden_hyp_vecs);
bp_base = (void *)__pkvm_create_private_mapping(phys, bp_base = (void *)__pkvm_create_private_mapping(phys,