The VHE hyp code has recently gained a few ISBs. Simplify this to one unconditional ISB in __kvm_vcpu_run_vhe(), and remove the unnecessary ISB from the kvm_call_hyp_ret() macro.
While kvm_call_hyp_ret() is also used to invoke __vgic_v3_get_gic_config(), but no ISB is necessary in that case either.
For the moment, an ISB is left in kvm_call_hyp(), as there are many more users, and removign the ISB would require a more thorough audit.
Suggested-by: Marc Zyngier maz@kernel.org Signed-off-by: Mark Rutland mark.rutland@arm.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Fuad Tabba tabba@google.com Cc: Marc Zyngier maz@kernel.org Cc: Mark Brown broonie@kernel.org Cc: Oliver Upton oliver.upton@linux.dev Cc: Will Deacon will@kernel.org --- arch/arm64/include/asm/kvm_host.h | 6 ++---- arch/arm64/kvm/hyp/include/hyp/debug-sr.h | 3 --- arch/arm64/kvm/hyp/vhe/switch.c | 25 +++++++++++------------ 3 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 382b382d14dac..2e3c152668eb8 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1289,9 +1289,8 @@ void kvm_arm_resume_guest(struct kvm *kvm); })
/* - * The couple of isb() below are there to guarantee the same behaviour - * on VHE as on !VHE, where the eret to EL1 acts as a context - * synchronization event. + * The isb() below is there to guarantee the same behaviour on VHE as on !VHE, + * where the eret to EL1 acts as a context synchronization event. */ #define kvm_call_hyp(f, ...) \ do { \ @@ -1309,7 +1308,6 @@ void kvm_arm_resume_guest(struct kvm *kvm); \ if (has_vhe()) { \ ret = f(__VA_ARGS__); \ - isb(); \ } else { \ ret = kvm_call_hyp_nvhe(f, ##__VA_ARGS__); \ } \ diff --git a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h index 73881e1dc2679..502a5b73ee70c 100644 --- a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h +++ b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h @@ -167,9 +167,6 @@ static inline void __debug_switch_to_host_common(struct kvm_vcpu *vcpu)
__debug_save_state(guest_dbg, guest_ctxt); __debug_restore_state(host_dbg, host_ctxt); - - if (has_vhe()) - isb(); }
#endif /* __ARM64_KVM_HYP_DEBUG_SR_H__ */ diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 32b4814eb2b7a..477f1580ffeaa 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -558,10 +558,10 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) host_ctxt = host_data_ptr(host_ctxt); guest_ctxt = &vcpu->arch.ctxt;
- sysreg_save_host_state_vhe(host_ctxt); - fpsimd_lazy_switch_to_guest(vcpu);
+ sysreg_save_host_state_vhe(host_ctxt); + /* * Note that ARM erratum 1165522 requires us to configure both stage 1 * and stage 2 translation for the guest context before we clear @@ -586,18 +586,23 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
__deactivate_traps(vcpu);
- /* Ensure CPTR trap deactivation has taken effect */ + sysreg_restore_host_state_vhe(host_ctxt); + + __debug_switch_to_host(vcpu); + + /* + * Ensure that all system register writes above have taken effect + * before returning to the host. In VHE mode, CPTR traps for + * FPSIMD/SVE/SME also apply to EL2, so FPSIMD/SVE/SME state must be + * manipulated after the ISB. + */ isb();
fpsimd_lazy_switch_to_host(vcpu);
- sysreg_restore_host_state_vhe(host_ctxt); - if (guest_owns_fp_regs()) __fpsimd_save_fpexc32(vcpu);
- __debug_switch_to_host(vcpu); - return exit_code; } NOKPROBE_SYMBOL(__kvm_vcpu_run_vhe); @@ -627,12 +632,6 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu) */ local_daif_restore(DAIF_PROCCTX_NOIRQ);
- /* - * When we exit from the guest we change a number of CPU configuration - * parameters, such as traps. We rely on the isb() in kvm_call_hyp*() - * to make sure these changes take effect before running the host or - * additional guests. - */ return ret; }