diff mbox series

[RFC,v2,3/3] riscv: KVM: Add Svukte extension support for Guest/VM

Message ID 20240927-dev-maxh-svukte-rebase-2-v2-3-9afe57c33aee@sifive.com (mailing list archive)
State New, archived
Headers show
Series riscv: add Svukte extension | expand

Commit Message

Max Hsu Sept. 27, 2024, 1:41 p.m. UTC 
Add KVM ISA extension ONE_REG interface to allow VMM tools to
detect and enable Svukte extension for Guest/VM.

Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Signed-off-by: Max Hsu <max.hsu@sifive.com>
---
 arch/riscv/include/uapi/asm/kvm.h | 1 +
 arch/riscv/kvm/vcpu_onereg.c      | 1 +
 2 files changed, 2 insertions(+)

Comments

Anup Patel Oct. 24, 2024, 7:16 p.m. UTC | #1 
On Fri, Sep 27, 2024 at 7:12 PM Max Hsu <max.hsu@sifive.com> wrote:
>
> Add KVM ISA extension ONE_REG interface to allow VMM tools to
> detect and enable Svukte extension for Guest/VM.
>
> Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
> Signed-off-by: Max Hsu <max.hsu@sifive.com>
> ---
>  arch/riscv/include/uapi/asm/kvm.h | 1 +
>  arch/riscv/kvm/vcpu_onereg.c      | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index e97db3296456e19f79ca02e4c4f70ae1b4abb48b..41b466b7ffaec421e8389d3f5b178580091a2c98 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -175,6 +175,7 @@ enum KVM_RISCV_ISA_EXT_ID {
>         KVM_RISCV_ISA_EXT_ZCF,
>         KVM_RISCV_ISA_EXT_ZCMOP,
>         KVM_RISCV_ISA_EXT_ZAWRS,
> +       KVM_RISCV_ISA_EXT_SVUKTE,
>         KVM_RISCV_ISA_EXT_MAX,
>  };
>
> diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> index b319c4c13c54ce22d2a7552f4c9f256a0c50780e..67237d6e53882a9fcd2cf265aa1704f25cc4a701 100644
> --- a/arch/riscv/kvm/vcpu_onereg.c
> +++ b/arch/riscv/kvm/vcpu_onereg.c
> @@ -41,6 +41,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
>         KVM_ISA_EXT_ARR(SVINVAL),
>         KVM_ISA_EXT_ARR(SVNAPOT),
>         KVM_ISA_EXT_ARR(SVPBMT),
> +       KVM_ISA_EXT_ARR(SVUKTE),
>         KVM_ISA_EXT_ARR(ZACAS),
>         KVM_ISA_EXT_ARR(ZAWRS),
>         KVM_ISA_EXT_ARR(ZBA),

The KVM_RISCV_ISA_EXT_SVUKTE should be added to the
switch-case in kvm_riscv_vcpu_isa_disable_allowed() because
hypervisor seems to have no way to disable Svukte for the Guest
when it's available on the Host.

Regards,
Anup
Max Hsu Nov. 4, 2024, 7:44 a.m. UTC | #2 
Hi Anup,

Thank you for the suggestion.

I’m not entirely sure if I fully understand it, but I believe the
hypervisor should be able to disable the Svukte extension.

Inside the switch-case of kvm_riscv_vcpu_isa_disable_allowed(),
the default case breaks and returns true.

So that means when the KVM_RISCV_ISA_EXT_SVUKTE passed into
kvm_riscv_vcpu_isa_disable_allowed() it will return true.

If I've misunderstood, please let me know.

Best regards,
Max Hsu

On Fri, Oct 25, 2024 at 3:17 AM Anup Patel <anup@brainfault.org> wrote:
>
> On Fri, Sep 27, 2024 at 7:12 PM Max Hsu <max.hsu@sifive.com> wrote:
> >
> > Add KVM ISA extension ONE_REG interface to allow VMM tools to
> > detect and enable Svukte extension for Guest/VM.
> >
> > Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
> > Signed-off-by: Max Hsu <max.hsu@sifive.com>
> > ---
> >  arch/riscv/include/uapi/asm/kvm.h | 1 +
> >  arch/riscv/kvm/vcpu_onereg.c      | 1 +
> >  2 files changed, 2 insertions(+)
> >
> > diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> > index e97db3296456e19f79ca02e4c4f70ae1b4abb48b..41b466b7ffaec421e8389d3f5b178580091a2c98 100644
> > --- a/arch/riscv/include/uapi/asm/kvm.h
> > +++ b/arch/riscv/include/uapi/asm/kvm.h
> > @@ -175,6 +175,7 @@ enum KVM_RISCV_ISA_EXT_ID {
> >         KVM_RISCV_ISA_EXT_ZCF,
> >         KVM_RISCV_ISA_EXT_ZCMOP,
> >         KVM_RISCV_ISA_EXT_ZAWRS,
> > +       KVM_RISCV_ISA_EXT_SVUKTE,
> >         KVM_RISCV_ISA_EXT_MAX,
> >  };
> >
> > diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> > index b319c4c13c54ce22d2a7552f4c9f256a0c50780e..67237d6e53882a9fcd2cf265aa1704f25cc4a701 100644
> > --- a/arch/riscv/kvm/vcpu_onereg.c
> > +++ b/arch/riscv/kvm/vcpu_onereg.c
> > @@ -41,6 +41,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
> >         KVM_ISA_EXT_ARR(SVINVAL),
> >         KVM_ISA_EXT_ARR(SVNAPOT),
> >         KVM_ISA_EXT_ARR(SVPBMT),
> > +       KVM_ISA_EXT_ARR(SVUKTE),
> >         KVM_ISA_EXT_ARR(ZACAS),
> >         KVM_ISA_EXT_ARR(ZAWRS),
> >         KVM_ISA_EXT_ARR(ZBA),
>
> The KVM_RISCV_ISA_EXT_SVUKTE should be added to the
> switch-case in kvm_riscv_vcpu_isa_disable_allowed() because
> hypervisor seems to have no way to disable Svukte for the Guest
> when it's available on the Host.
>
> Regards,
> Anup
Anup Patel Nov. 4, 2024, 1:19 p.m. UTC | #3 
On Mon, Nov 4, 2024 at 1:14 PM Max Hsu <max.hsu@sifive.com> wrote:
>
> Hi Anup,
>
> Thank you for the suggestion.
>
> I’m not entirely sure if I fully understand it, but I believe the
> hypervisor should be able to disable the Svukte extension.
>
> Inside the switch-case of kvm_riscv_vcpu_isa_disable_allowed(),
> the default case breaks and returns true.
>
> So that means when the KVM_RISCV_ISA_EXT_SVUKTE passed into
> kvm_riscv_vcpu_isa_disable_allowed() it will return true.
>
> If I've misunderstood, please let me know.

I don't see any code in this patch which disables/enables Svukte for
Guest based on KVM ONE_REG interface.

Regards,
Anup

>
> Best regards,
> Max Hsu
>
> On Fri, Oct 25, 2024 at 3:17 AM Anup Patel <anup@brainfault.org> wrote:
> >
> > On Fri, Sep 27, 2024 at 7:12 PM Max Hsu <max.hsu@sifive.com> wrote:
> > >
> > > Add KVM ISA extension ONE_REG interface to allow VMM tools to
> > > detect and enable Svukte extension for Guest/VM.
> > >
> > > Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
> > > Signed-off-by: Max Hsu <max.hsu@sifive.com>
> > > ---
> > >  arch/riscv/include/uapi/asm/kvm.h | 1 +
> > >  arch/riscv/kvm/vcpu_onereg.c      | 1 +
> > >  2 files changed, 2 insertions(+)
> > >
> > > diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> > > index e97db3296456e19f79ca02e4c4f70ae1b4abb48b..41b466b7ffaec421e8389d3f5b178580091a2c98 100644
> > > --- a/arch/riscv/include/uapi/asm/kvm.h
> > > +++ b/arch/riscv/include/uapi/asm/kvm.h
> > > @@ -175,6 +175,7 @@ enum KVM_RISCV_ISA_EXT_ID {
> > >         KVM_RISCV_ISA_EXT_ZCF,
> > >         KVM_RISCV_ISA_EXT_ZCMOP,
> > >         KVM_RISCV_ISA_EXT_ZAWRS,
> > > +       KVM_RISCV_ISA_EXT_SVUKTE,
> > >         KVM_RISCV_ISA_EXT_MAX,
> > >  };
> > >
> > > diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
> > > index b319c4c13c54ce22d2a7552f4c9f256a0c50780e..67237d6e53882a9fcd2cf265aa1704f25cc4a701 100644
> > > --- a/arch/riscv/kvm/vcpu_onereg.c
> > > +++ b/arch/riscv/kvm/vcpu_onereg.c
> > > @@ -41,6 +41,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
> > >         KVM_ISA_EXT_ARR(SVINVAL),
> > >         KVM_ISA_EXT_ARR(SVNAPOT),
> > >         KVM_ISA_EXT_ARR(SVPBMT),
> > > +       KVM_ISA_EXT_ARR(SVUKTE),
> > >         KVM_ISA_EXT_ARR(ZACAS),
> > >         KVM_ISA_EXT_ARR(ZAWRS),
> > >         KVM_ISA_EXT_ARR(ZBA),
> >
> > The KVM_RISCV_ISA_EXT_SVUKTE should be added to the
> > switch-case in kvm_riscv_vcpu_isa_disable_allowed() because
> > hypervisor seems to have no way to disable Svukte for the Guest
> > when it's available on the Host.
> >
> > Regards,
> > Anup
>
diff mbox series

Patch

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index e97db3296456e19f79ca02e4c4f70ae1b4abb48b..41b466b7ffaec421e8389d3f5b178580091a2c98 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -175,6 +175,7 @@  enum KVM_RISCV_ISA_EXT_ID {
 	KVM_RISCV_ISA_EXT_ZCF,
 	KVM_RISCV_ISA_EXT_ZCMOP,
 	KVM_RISCV_ISA_EXT_ZAWRS,
+	KVM_RISCV_ISA_EXT_SVUKTE,
 	KVM_RISCV_ISA_EXT_MAX,
 };
 
diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
index b319c4c13c54ce22d2a7552f4c9f256a0c50780e..67237d6e53882a9fcd2cf265aa1704f25cc4a701 100644
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
@@ -41,6 +41,7 @@  static const unsigned long kvm_isa_ext_arr[] = {
 	KVM_ISA_EXT_ARR(SVINVAL),
 	KVM_ISA_EXT_ARR(SVNAPOT),
 	KVM_ISA_EXT_ARR(SVPBMT),
+	KVM_ISA_EXT_ARR(SVUKTE),
 	KVM_ISA_EXT_ARR(ZACAS),
 	KVM_ISA_EXT_ARR(ZAWRS),
 	KVM_ISA_EXT_ARR(ZBA),