diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/vhe/switch.c | 21 |
2 files changed, 20 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index e98cfe7855a6..12adab97e7f2 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -654,6 +654,7 @@ struct kvm_host_data { #define KVM_HOST_DATA_FLAG_HAS_TRBE 1 #define KVM_HOST_DATA_FLAG_TRBE_ENABLED 4 #define KVM_HOST_DATA_FLAG_EL1_TRACING_CONFIGURED 5 +#define KVM_HOST_DATA_FLAG_VCPU_IN_HYP_CONTEXT 6 unsigned long flags; struct kvm_cpu_context host_ctxt; diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 731a0378ed13..220dee8a45e0 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -53,13 +53,23 @@ static u64 __compute_hcr(struct kvm_vcpu *vcpu) if (!vcpu_has_nv(vcpu)) return hcr; + /* + * We rely on the invariant that a vcpu entered from HYP + * context must also exit in the same context, as only an ERET + * instruction can kick us out of it, and we obviously trap + * that sucker. PSTATE.M will get fixed-up on exit. + */ if (is_hyp_ctxt(vcpu)) { + host_data_set_flag(VCPU_IN_HYP_CONTEXT); + hcr |= HCR_NV | HCR_NV2 | HCR_AT | HCR_TTLB; if (!vcpu_el2_e2h_is_set(vcpu)) hcr |= HCR_NV1; write_sysreg_s(vcpu->arch.ctxt.vncr_array, SYS_VNCR_EL2); + } else { + host_data_clear_flag(VCPU_IN_HYP_CONTEXT); } return hcr | (__vcpu_sys_reg(vcpu, HCR_EL2) & ~NV_HCR_GUEST_EXCLUDE); @@ -568,9 +578,12 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) /* * If we were in HYP context on entry, adjust the PSTATE view - * so that the usual helpers work correctly. + * so that the usual helpers work correctly. This enforces our + * invariant that the guest's HYP context status is preserved + * across a run. */ - if (vcpu_has_nv(vcpu) && (read_sysreg(hcr_el2) & HCR_NV)) { + if (vcpu_has_nv(vcpu) && + unlikely(host_data_test_flag(VCPU_IN_HYP_CONTEXT))) { u64 mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT); switch (mode) { @@ -586,6 +599,10 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) *vcpu_cpsr(vcpu) |= mode; } + /* Apply extreme paranoia! */ + BUG_ON(vcpu_has_nv(vcpu) && + !!host_data_test_flag(VCPU_IN_HYP_CONTEXT) != is_hyp_ctxt(vcpu)); + return __fixup_guest_exit(vcpu, exit_code, hyp_exit_handlers); } |