Nianyao,
Please do not send patches as HTML. Or any email as HTML. Please make
sure that you only send plain text emails on any mailing list (see point
#6 in Documentation/process/submitting-patches.rst).
On 12/03/2019 12:22, Tangnianyao (ICT) wrote:
> In gicv4, direct vlpi may be forward to PE without using LR or ap_list. If
>
> ICH_HCR_EL2.En is 0 in guest, direct vlpi cannot be accepted by PE.
>
> It will take long time for direct vlpi to be forwarded in some cases.
>
> Direct vlpi has to wait for ICH_HCR_EL2.En=1 where some other interrupts
>
> using LR need to be forwarded, because in kvm_vgic_flush_hwstate,
>
> if ap_list is empty, it will return quickly not setting ICH_HCR_EL2.En.
>
> To fix this, set ICH_HCR_EL2.En to 1 before returning to guest when
>
> using GICv4.
>
>
>
> Signed-off-by: Nianyao Tang <tangnianyao@xxxxxxxxxx>
>
> ---
>
> arch/arm64/include/asm/kvm_asm.h | 1 +
>
> virt/kvm/arm/hyp/vgic-v3-sr.c | 10 ++++++++++
>
> virt/kvm/arm/vgic/vgic-v4.c | 8 ++++++++
>
> 3 files changed, 19 insertions(+)
>
>
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h
> b/arch/arm64/include/asm/kvm_asm.h
>
> index f5b79e9..0581c4d 100644
>
> --- a/arch/arm64/include/asm/kvm_asm.h
>
> +++ b/arch/arm64/include/asm/kvm_asm.h
>
> @@ -79,6 +79,7 @@
>
> extern void __vgic_v3_init_lrs(void);
>
> extern u32 __kvm_get_mdcr_el2(void);
>
> +extern void __vgic_v3_write_hcr(u32 vmcr);
>
> /* Home-grown __this_cpu_{ptr,read} variants that always work at HYP */
>
> #define
> __hyp_this_cpu_ptr(sym)
> \
>
> diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
>
> index 264d92d..12027af 100644
>
> --- a/virt/kvm/arm/hyp/vgic-v3-sr.c
>
> +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
>
> @@ -434,6 +434,16 @@ void __hyp_text __vgic_v3_write_vmcr(u32 vmcr)
>
> write_gicreg(vmcr, ICH_VMCR_EL2);
>
> }
>
> +u64 __hyp_text __vgic_v3_read_hcr(void)
>
> +{
>
> + return read_gicreg(ICH_HCR_EL2);
>
> +}
>
> +
>
> +void __hyp_text __vgic_v3_write_hcr(u32 vmcr)
>
> +{
>
> + write_gicreg(vmcr, ICH_HCR_EL2);
>
> +}
This is HYP code...
>
> +
>
> #ifdef CONFIG_ARM64
>
> static int __hyp_text __vgic_v3_bpr_min(void)
>
> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
>
> index 1ed5f22..515171a 100644
>
> --- a/virt/kvm/arm/vgic/vgic-v4.c
>
> +++ b/virt/kvm/arm/vgic/vgic-v4.c
>
> @@ -208,6 +208,8 @@ int vgic_v4_sync_hwstate(struct kvm_vcpu *vcpu)
>
> if (!vgic_supports_direct_msis(vcpu->kvm))
>
> return 0;
>
> + __vgic_v3_write_hcr(vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr &
> ~ICH_HCR_EN);
And you've now crashed your non-VHE system by branching directly to code
that cannot be executed at EL1.
>
> +
>
> return its_schedule_vpe(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe, false);
>
> }
>
> @@ -220,6 +222,12 @@ int vgic_v4_flush_hwstate(struct kvm_vcpu *vcpu)
>
> return 0;
>
> /*
>
> + * Enable ICH_HCR_EL.En so that guest can accpet and handle direct
>
> + * vlpi.
>
> + */
>
> + __vgic_v3_write_hcr(vcpu->arch.vgic_cpu.vgic_v3.vgic_hcr);
>
> +
>
> + /*
>
> * Before making the VPE resident, make sure the redistributor
>
> * corresponding to our current CPU expects us here. See the
>
> * doc in drivers/irqchip/irq-gic-v4.c to understand how this
>
> --
>
> 1.9.1
>
>
>
>
>
Overall, this looks like the wrong approach. It is not the GICv4 code's
job to do this, but the low-level code (either the load/put code for VHE
or the save/restore code for non-VHE).
It would certainly help if you could describe which context you're in
(VHE, non-VHE). I suppose the former...
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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