On Thu, Dec 06, 2018 at 05:31:24PM +0000, Marc Zyngier wrote:
> In order to ensure that slipping HCR_EL2.TGE is done at the right
> time when switching translation regime, let insert the required ISBs
> that will be patched in when erratum 1165522 is detected.
>
> Take this opportunity to add the missing include of asm/alternative.h
> which was getting there by pure luck.
>
> Reviewed-by: James Morse <james.morse@xxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> ---
> arch/arm64/include/asm/kvm_hyp.h | 8 ++++++++
> arch/arm64/kvm/hyp/switch.c | 19 +++++++++++++++++++
> 2 files changed, 27 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
> index 23aca66767f9..a80a7ef57325 100644
> --- a/arch/arm64/include/asm/kvm_hyp.h
> +++ b/arch/arm64/include/asm/kvm_hyp.h
> @@ -20,6 +20,7 @@
>
> #include <linux/compiler.h>
> #include <linux/kvm_host.h>
> +#include <asm/alternative.h>
> #include <asm/sysreg.h>
>
> #define __hyp_text __section(.hyp.text) notrace
> @@ -163,6 +164,13 @@ static __always_inline void __hyp_text __load_guest_stage2(struct kvm *kvm)
> {
> write_sysreg(kvm->arch.vtcr, vtcr_el2);
> write_sysreg(kvm->arch.vttbr, vttbr_el2);
> +
> + /*
> + * ARM erratum 1165522 requires the actual execution of the above
> + * before we can switch to the EL1/EL0 translation regime used by
> + * the guest.
> + */
> + asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522));
> }
>
> #endif /* __ARM64_KVM_HYP_H__ */
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index a8fa61c68c32..31ee0bfc432f 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -143,6 +143,14 @@ static void deactivate_traps_vhe(void)
> {
> extern char vectors[]; /* kernel exception vectors */
> write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
> +
> + /*
> + * ARM erratum 1165522 requires the actual execution of the above
> + * before we can switch to the EL2/EL0 translation regime used by
> + * the host.
> + */
> + asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522));
> +
> write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
> write_sysreg(vectors, vbar_el1);
> }
> @@ -499,6 +507,17 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
>
> sysreg_save_host_state_vhe(host_ctxt);
>
> + /*
> + * ARM erratum 1165522 requires us to configure both stage 1 and
> + * stage 2 translation for the guest context before we clear
> + * HCR_EL2.TGE.
> + *
> + * We have already configured the guest's stage 1 translation in
> + * kvm_vcpu_load_sysregs above. We must now call __activate_vm
> + * before __activate_traps, because __activate_vm configures
> + * stage 2 translation, and __activate_traps clear HCR_EL2.TGE
> + * (among other things).
> + */
> __activate_vm(vcpu->kvm);
> __activate_traps(vcpu);
>
> --
> 2.19.2
>
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxx>
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