The run struct affects how hyp handles the guest's state so it needs to
be kept safe from the host in protected mode. Copy the relevant values
into hyp-private memory while running a vcpu to achieve this.
In the traditional, non-protected, mode, there's no need to protect the
values from the host so the run struct in host memory is used directly.
Signed-off-by: Andrew Scull <ascull@xxxxxxxxxx>
---
arch/arm64/kvm/hyp/nvhe/switch.c | 33 +++++++++++++++++++++++++++++---
1 file changed, 30 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 076c2200324f..a0fbaf0ee309 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -165,9 +165,26 @@ static void __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
write_sysreg(pmu->events_host, pmcntenset_el0);
}
+/* Snapshot state from the host to private memory and sanitize them. */
+void __sync_vcpu_before_run(struct kvm_vcpu *vcpu, struct kvm_vcpu_arch_run *run)
+{
+ run->flags = vcpu->arch.run.flags;
+
+ /* Clear host state to make misuse apparent. */
+ vcpu->arch.run.flags = 0;
+}
+
+/* Sanitize the run state before writing it back to the host. */
+void __sync_vcpu_after_run(struct kvm_vcpu *vcpu, struct kvm_vcpu_arch_run *run)
+{
+ vcpu->arch.run.flags = run->flags;
+}
+
/* Switch to the guest for legacy non-VHE systems */
int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
{
+ struct kvm_vcpu_arch_run protected_run;
+ struct kvm_vcpu_arch_run *run;
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
bool pmu_switch_needed;
@@ -184,6 +201,13 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
pmr_sync();
}
+ if (is_protected_kvm_enabled()) {
+ run = &protected_run;
+ __sync_vcpu_before_run(vcpu, run);
+ } else {
+ run = &vcpu->arch.run;
+ }
+
host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;
@@ -206,7 +230,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
__sysreg_restore_state_nvhe(guest_ctxt);
__load_guest_stage2(kern_hyp_va(vcpu->arch.hw_mmu));
- __activate_traps(vcpu, &vcpu->arch.run);
+ __activate_traps(vcpu, run);
__hyp_vgic_restore_state(vcpu);
__timer_enable_traps(vcpu);
@@ -218,7 +242,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
exit_code = __guest_enter(vcpu);
/* And we're baaack! */
- } while (fixup_guest_exit(vcpu, &vcpu->arch.run, &exit_code));
+ } while (fixup_guest_exit(vcpu, run, &exit_code));
__sysreg_save_state_nvhe(guest_ctxt);
__sysreg32_save_state(vcpu);
@@ -230,7 +254,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
__sysreg_restore_state_nvhe(host_ctxt);
- if (vcpu->arch.run.flags & KVM_ARM64_RUN_FP_ENABLED)
+ if (run->flags & KVM_ARM64_RUN_FP_ENABLED)
__fpsimd_save_fpexc32(vcpu);
/*
@@ -248,6 +272,9 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
host_ctxt->__hyp_running_vcpu = NULL;
+ if (is_protected_kvm_enabled())
+ __sync_vcpu_after_run(vcpu, run);
+
return exit_code;
}
--
2.30.1.766.gb4fecdf3b7-goog
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