[PATCH -fixes v2] RISC-V: KVM: Require HAVE_KVM

[PATCH -fixes v2] RISC-V: KVM: Require HAVE_KVM

[Andrew Jones]

KVM requires EVENTFD, which is selected by HAVE_KVM. Other KVM
supporting architectures select HAVE_KVM and then their KVM
Kconfigs ensure its there with a depends on HAVE_KVM. Make RISCV
consistent with that approach which fixes configs which have KVM
but not EVENTFD, as was discovered with a randconfig test.

Fixes: 99cdc6c18c2d ("RISC-V: Add initial skeletal KVM support")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/all/44907c6b-c5bd-4e4a-a921-e4d3825539d8@infradead.org/
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---

v2:
 - Added Fixes tag and -fixes prefix [Alexandre/Anup]

 arch/riscv/Kconfig     | 1 +
 arch/riscv/kvm/Kconfig | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a935a5f736b9..daba06a3b76f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -128,6 +128,7 @@ config RISCV
 	select HAVE_KPROBES if !XIP_KERNEL
 	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
 	select HAVE_KRETPROBES if !XIP_KERNEL
+	select HAVE_KVM
 	# https://github.com/ClangBuiltLinux/linux/issues/1881
 	select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
 	select HAVE_MOVE_PMD
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 1fd76aee3b71..36fa8ec9e5ba 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -19,7 +19,7 @@ if VIRTUALIZATION
 
 config KVM
 	tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
-	depends on RISCV_SBI && MMU
+	depends on HAVE_KVM && RISCV_SBI && MMU
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_MSI
-- 
2.43.0

Re: [PATCH -fixes v2] RISC-V: KVM: Require HAVE_KVM

[Randy Dunlap]

On 1/4/24 04:37, Andrew Jones wrote:
> KVM requires EVENTFD, which is selected by HAVE_KVM. Other KVM
> supporting architectures select HAVE_KVM and then their KVM
> Kconfigs ensure its there with a depends on HAVE_KVM. Make RISCV
> consistent with that approach which fixes configs which have KVM
> but not EVENTFD, as was discovered with a randconfig test.
> 
> Fixes: 99cdc6c18c2d ("RISC-V: Add initial skeletal KVM support")
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Closes: https://lore.kernel.org/all/44907c6b-c5bd-4e4a-a921-e4d3825539d8@infradead.org/
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>


Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested

Thanks.


> ---
> 
> v2:
>  - Added Fixes tag and -fixes prefix [Alexandre/Anup]
> 
>  arch/riscv/Kconfig     | 1 +
>  arch/riscv/kvm/Kconfig | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index a935a5f736b9..daba06a3b76f 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -128,6 +128,7 @@ config RISCV
>  	select HAVE_KPROBES if !XIP_KERNEL
>  	select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
>  	select HAVE_KRETPROBES if !XIP_KERNEL
> +	select HAVE_KVM
>  	# https://github.com/ClangBuiltLinux/linux/issues/1881
>  	select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
>  	select HAVE_MOVE_PMD
> diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
> index 1fd76aee3b71..36fa8ec9e5ba 100644
> --- a/arch/riscv/kvm/Kconfig
> +++ b/arch/riscv/kvm/Kconfig
> @@ -19,7 +19,7 @@ if VIRTUALIZATION
>  
>  config KVM
>  	tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
> -	depends on RISCV_SBI && MMU
> +	depends on HAVE_KVM && RISCV_SBI && MMU
>  	select HAVE_KVM_IRQCHIP
>  	select HAVE_KVM_IRQ_ROUTING
>  	select HAVE_KVM_MSI

-- 
#Randy

Re: [PATCH -fixes v2] RISC-V: KVM: Require HAVE_KVM

[Anup Patel]

On Thu, Jan 4, 2024 at 6:07 PM Andrew Jones <ajones@ventanamicro.com> wrote:
>
> KVM requires EVENTFD, which is selected by HAVE_KVM. Other KVM
> supporting architectures select HAVE_KVM and then their KVM
> Kconfigs ensure its there with a depends on HAVE_KVM. Make RISCV
> consistent with that approach which fixes configs which have KVM
> but not EVENTFD, as was discovered with a randconfig test.
>
> Fixes: 99cdc6c18c2d ("RISC-V: Add initial skeletal KVM support")
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Closes: https://lore.kernel.org/all/44907c6b-c5bd-4e4a-a921-e4d3825539d8@infradead.org/
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>

Queued this patch for Linux-6.8

Regards,
Anup

> ---
>
> v2:
>  - Added Fixes tag and -fixes prefix [Alexandre/Anup]
>
>  arch/riscv/Kconfig     | 1 +
>  arch/riscv/kvm/Kconfig | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index a935a5f736b9..daba06a3b76f 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -128,6 +128,7 @@ config RISCV
>         select HAVE_KPROBES if !XIP_KERNEL
>         select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
>         select HAVE_KRETPROBES if !XIP_KERNEL
> +       select HAVE_KVM
>         # https://github.com/ClangBuiltLinux/linux/issues/1881
>         select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if !LD_IS_LLD
>         select HAVE_MOVE_PMD
> diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
> index 1fd76aee3b71..36fa8ec9e5ba 100644
> --- a/arch/riscv/kvm/Kconfig
> +++ b/arch/riscv/kvm/Kconfig
> @@ -19,7 +19,7 @@ if VIRTUALIZATION
>
>  config KVM
>         tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
> -       depends on RISCV_SBI && MMU
> +       depends on HAVE_KVM && RISCV_SBI && MMU
>         select HAVE_KVM_IRQCHIP
>         select HAVE_KVM_IRQ_ROUTING
>         select HAVE_KVM_MSI
> --
> 2.43.0
>

Re: [PATCH -fixes v2] RISC-V: KVM: Require HAVE_KVM

[Sean Christopherson]

On Thu, Jan 18, 2024, Anup Patel wrote:
> On Thu, Jan 4, 2024 at 6:07 PM Andrew Jones <ajones@ventanamicro.com> wrote:
> >
> > KVM requires EVENTFD, which is selected by HAVE_KVM. Other KVM
> > supporting architectures select HAVE_KVM and then their KVM
> > Kconfigs ensure its there with a depends on HAVE_KVM. Make RISCV
> > consistent with that approach which fixes configs which have KVM
> > but not EVENTFD, as was discovered with a randconfig test.
> >
> > Fixes: 99cdc6c18c2d ("RISC-V: Add initial skeletal KVM support")
> > Reported-by: Randy Dunlap <rdunlap@infradead.org>
> > Closes: https://lore.kernel.org/all/44907c6b-c5bd-4e4a-a921-e4d3825539d8@infradead.org/
> > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> 
> Queued this patch for Linux-6.8

That should be unnecessary.  Commit caadf876bb74 ("KVM: introduce CONFIG_KVM_COMMON"),
which is in Paolo's pull request for 6.8, addresses the EVENTFD issue.  And the
rest of Paolo's series[*], which presumably will get queued for 6.9, eliminates
HAVE_KVM entirely.

[*] https://lore.kernel.org/all/20240108124740.114453-6-pbonzini@redhat.com

Re: [PATCH -fixes v2] RISC-V: KVM: Require HAVE_KVM

[Anup Patel]

On Thu, Jan 18, 2024 at 11:10 PM Sean Christopherson <seanjc@google.com> wrote:
>
> On Thu, Jan 18, 2024, Anup Patel wrote:
> > On Thu, Jan 4, 2024 at 6:07 PM Andrew Jones <ajones@ventanamicro.com> wrote:
> > >
> > > KVM requires EVENTFD, which is selected by HAVE_KVM. Other KVM
> > > supporting architectures select HAVE_KVM and then their KVM
> > > Kconfigs ensure its there with a depends on HAVE_KVM. Make RISCV
> > > consistent with that approach which fixes configs which have KVM
> > > but not EVENTFD, as was discovered with a randconfig test.
> > >
> > > Fixes: 99cdc6c18c2d ("RISC-V: Add initial skeletal KVM support")
> > > Reported-by: Randy Dunlap <rdunlap@infradead.org>
> > > Closes: https://lore.kernel.org/all/44907c6b-c5bd-4e4a-a921-e4d3825539d8@infradead.org/
> > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> >
> > Queued this patch for Linux-6.8
>
> That should be unnecessary.  Commit caadf876bb74 ("KVM: introduce CONFIG_KVM_COMMON"),
> which is in Paolo's pull request for 6.8, addresses the EVENTFD issue.  And the
> rest of Paolo's series[*], which presumably will get queued for 6.9, eliminates
> HAVE_KVM entirely.
>
> [*] https://lore.kernel.org/all/20240108124740.114453-6-pbonzini@redhat.com

I was not sure about the timeline of when Paolo's series would be merged
hence thought of taking this patch as a fix.

For now, I will drop this patch from my queue. If required we can have it
as a 6.8-rc fix.

Regards,
Anup