[PATCH v12 1/6] KVM: Add architecture-defined TLB flush support

[PATCH v12 1/6] KVM: Add architecture-defined TLB flush support

[Mario Smarduch]

This patch adds support for architecture implemented VM TLB flush, currently
ARMv7 defines HAVE_KVM_ARCH_TLB_FLUSH_ALL. This leaves other architectures 
unaffected using the generic version. In subsequent patch ARMv7 defines
HAVE_KVM_ARCH_TLB_FLUSH_ALL and it's own TLB flush interface.

Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
---
 virt/kvm/Kconfig    |    3 +++
 virt/kvm/kvm_main.c |    2 ++
 2 files changed, 5 insertions(+)

diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index fc0c5e6..3796a21 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -37,3 +37,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT
 
 config KVM_VFIO
        bool
+
+config HAVE_KVM_ARCH_TLB_FLUSH_ALL
+       bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 33712fb..887df87 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -184,6 +184,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
 	return called;
 }
 
+#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
 void kvm_flush_remote_tlbs(struct kvm *kvm)
 {
 	long dirty_count = kvm->tlbs_dirty;
@@ -194,6 +195,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
 	cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
+#endif
 
 void kvm_reload_remote_mmus(struct kvm *kvm)
 {
-- 
1.7.9.5

Re: [PATCH v12 1/6] KVM: Add architecture-defined TLB flush support

[Cornelia Huck]

On Wed, 22 Oct 2014 15:34:06 -0700
Mario Smarduch <m.smarduch@samsung.com> wrote:

> This patch adds support for architecture implemented VM TLB flush, currently
> ARMv7 defines HAVE_KVM_ARCH_TLB_FLUSH_ALL. This leaves other architectures 
> unaffected using the generic version. In subsequent patch ARMv7 defines
> HAVE_KVM_ARCH_TLB_FLUSH_ALL and it's own TLB flush interface.

Can you reword this a bit?

"Allow architectures to override the generic kvm_flush_remote_tlbs()
function via HAVE_KVM_ARCH_TLB_FLUSH_ALL. ARMv7 will need this to
provide its own TLB flush interface."

> 
> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
> ---
>  virt/kvm/Kconfig    |    3 +++
>  virt/kvm/kvm_main.c |    2 ++
>  2 files changed, 5 insertions(+)

Providing an override for the special cases looks sane to me.

Re: [PATCH v12 1/6] KVM: Add architecture-defined TLB flush support

[Paolo Bonzini]

On 23/10/2014 00:34, Mario Smarduch wrote:
> This patch adds support for architecture implemented VM TLB flush, currently
> ARMv7 defines HAVE_KVM_ARCH_TLB_FLUSH_ALL. This leaves other architectures 
> unaffected using the generic version. In subsequent patch ARMv7 defines
> HAVE_KVM_ARCH_TLB_FLUSH_ALL and it's own TLB flush interface.
> 
> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
> ---
>  virt/kvm/Kconfig    |    3 +++
>  virt/kvm/kvm_main.c |    2 ++
>  2 files changed, 5 insertions(+)
> 
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index fc0c5e6..3796a21 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -37,3 +37,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT
>  
>  config KVM_VFIO
>         bool
> +
> +config HAVE_KVM_ARCH_TLB_FLUSH_ALL
> +       bool
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 33712fb..887df87 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -184,6 +184,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
>  	return called;
>  }
>  
> +#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
>  void kvm_flush_remote_tlbs(struct kvm *kvm)
>  {
>  	long dirty_count = kvm->tlbs_dirty;
> @@ -194,6 +195,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
>  	cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
>  }
>  EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
> +#endif
>  
>  void kvm_reload_remote_mmus(struct kvm *kvm)
>  {
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>