Re: [PATCH 1/2] riscv: kvm: Add KVM_GET_REG_LIST API support

Haibo Xu
2023-05-15T06:23:34Z

On Fri, May 12, 2023 at 12:40 AM Andrew Jones <ajones@ventanamicro.com> wrote:
>
> On Thu, May 11, 2023 at 05:22:48PM +0800, Haibo Xu wrote:
> > KVM_GET_REG_LIST API will return all registers that are available to
> > KVM_GET/SET_ONE_REG APIs. It's very useful to identify some platform
> > regression issue during VM migration.
> >
> > Since this API was already supported on arm64, it'd be straightforward
> > to enable it on riscv with similar code structure.
> >
> > Signed-off-by: Haibo Xu <haibo1.xu@intel.com>
> > ---
> > Documentation/virt/kvm/api.rst | 2 +-
> > arch/riscv/kvm/vcpu.c | 346 +++++++++++++++++++++++++++++++++
> > 2 files changed, 347 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> > index add067793b90..280e89abd004 100644
> > --- a/Documentation/virt/kvm/api.rst
> > +++ b/Documentation/virt/kvm/api.rst
> > @@ -3499,7 +3499,7 @@ VCPU matching underlying host.
> > ---------------------
> >
> > :Capability: basic
> > -:Architectures: arm64, mips
> > +:Architectures: arm64, mips, riscv
> > :Type: vcpu ioctl
> > :Parameters: struct kvm_reg_list (in/out)
> > :Returns: 0 on success; -1 on error
> > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> > index 8bd9f2a8a0b9..fb8834e4fa15 100644
> > --- a/arch/riscv/kvm/vcpu.c
> > +++ b/arch/riscv/kvm/vcpu.c
> > @@ -657,6 +657,334 @@ static int kvm_riscv_vcpu_set_reg_isa_ext(struct kvm_vcpu *vcpu,
> > return 0;
> > }
> >
> > +static inline unsigned long num_config_regs(void)
> > +{
> > + return sizeof(struct kvm_riscv_config) / sizeof(unsigned long);
>
> We can't assume all config registers are present. For example,
> zicbom and zicboz block size registers are only present when their
> respective extensions are available.
>
> Thanks,
> drew

Yes, I will filter out these kinds of registers in the next version.

Thanks,
Haibo