Re: [PATCH v7 16/30] LoongArch: KVM: Implement update VM id function

[Tianrui Zhao]

在 2023年04月19日 10:01, Huacai Chen 写道:
> Hi, Tianrui,
>
> On Mon, Apr 17, 2023 at 5:47 PM Tianrui Zhao <zhaotianrui@xxxxxxxxxxx> wrote:
> > Implement kvm check vmid and update vmid, the vmid should be checked before
> > vcpu enter guest.
> >
> > Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
> > ---
> >   arch/loongarch/kvm/vmid.c | 65 +++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 65 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 000000000000..7d9688c24184
> > --- /dev/null
> > +++ b/arch/loongarch/kvm/vmid.c
> > @@ -0,0 +1,65 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
> > + */
> > +
> > +#include <linux/kvm_host.h>
> > +#include <asm/kvm_host.h>
> linux/kvm_host.h already include asm/kvm_host.h
>
> Huacai
Thanks, I will remove the asm/kvm_host.h.

Thanks
Tianrui Zhao
> > +#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, int cpu)
> > +{
> > +       struct kvm_context *context;
> > +       bool migrated;
> > +       unsigned long ver, old, vpid;
> > +
> > +       /*
> > +        * 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->arch.last_exec_cpu != cpu);
> > +       vcpu->arch.last_exec_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);
> > +       }
> > +
> > +       /* Restore GSTAT(0x50).vpid */
> > +       vpid = (vcpu->arch.vpid & vpid_mask)
> > +               << CSR_GSTAT_GID_SHIFT;
> > +       change_csr_gstat(vpid_mask << CSR_GSTAT_GID_SHIFT, vpid);
> > +}
> > --
> > 2.31.1