Hi, Tianrui,
On Thu, Aug 31, 2023 at 4:30 PM Tianrui Zhao <zhaotianrui@xxxxxxxxxxx> wrote:
>
> Implement kvm check vmid and update vmid, the vmid should be checked before
> vcpu enter guest.
>
> Reviewed-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
> ---
> arch/loongarch/kvm/vmid.c | 66 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 66 insertions(+)
> create mode 100644 arch/loongarch/kvm/vmid.c
>
> diff --git a/arch/loongarch/kvm/vmid.c b/arch/loongarch/kvm/vmid.c
> new file mode 100644
> index 0000000000..fc25ddc3b7
> --- /dev/null
> +++ b/arch/loongarch/kvm/vmid.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
> + */
> +
> +#include <linux/kvm_host.h>
> +#include "trace.h"
> +
> +static void _kvm_update_vpid(struct kvm_vcpu *vcpu, int cpu)
> +{
> + struct kvm_context *context;
> + unsigned long vpid;
> +
> + context = per_cpu_ptr(vcpu->kvm->arch.vmcs, cpu);
> + vpid = context->vpid_cache + 1;
> + if (!(vpid & vpid_mask)) {
> + /* finish round of 64 bit loop */
> + if (unlikely(!vpid))
> + vpid = vpid_mask + 1;
> +
> + /* vpid 0 reserved for root */
> + ++vpid;
> +
> + /* start new vpid cycle */
> + kvm_flush_tlb_all();
> + }
> +
> + context->vpid_cache = vpid;
> + vcpu->arch.vpid = vpid;
> +}
> +
> +void _kvm_check_vmid(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_context *context;
> + bool migrated;
> + unsigned long ver, old, vpid;
> + int cpu;
> +
> + cpu = smp_processor_id();
> + /*
> + * Are we entering guest context on a different CPU to last time?
> + * If so, the vCPU's guest TLB state on this CPU may be stale.
> + */
> + context = per_cpu_ptr(vcpu->kvm->arch.vmcs, cpu);
> + migrated = (vcpu->cpu != cpu);
> +
> + /*
> + * Check if our vpid is of an older version
> + *
> + * We also discard the stored vpid if we've executed on
> + * another CPU, as the guest mappings may have changed without
> + * hypervisor knowledge.
> + */
> + ver = vcpu->arch.vpid & ~vpid_mask;
> + old = context->vpid_cache & ~vpid_mask;
> + if (migrated || (ver != old)) {
> + _kvm_update_vpid(vcpu, cpu);
> + trace_kvm_vpid_change(vcpu, vcpu->arch.vpid);
> + vcpu->cpu = cpu;
> + }
> +
> + /* Restore GSTAT(0x50).vpid */
> + vpid = (vcpu->arch.vpid & vpid_mask)
> + << CSR_GSTAT_GID_SHIFT;
> + change_csr_gstat(vpid_mask << CSR_GSTAT_GID_SHIFT, vpid);
> +}
I believe that vpid and vmid are both GID in the gstat register, so
please unify their names. And I think vpid is better than vmid.
Moreover, no need to create a vmid.c file, just putting them in main.c is OK.
Huacai
> --
> 2.27.0
>
