* Re: [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-14 12:10 ` [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS Andrew Jones
@ 2013-09-15 9:30 ` Gleb Natapov
2013-09-16 8:09 ` Marc Zyngier
2013-09-17 21:42 ` Christoffer Dall
2013-09-24 14:09 ` [PATCH v2] " Andrew Jones
2 siblings, 1 reply; 17+ messages in thread
From: Gleb Natapov @ 2013-09-15 9:30 UTC (permalink / raw)
To: Andrew Jones
Cc: kvmarm, kvm, catalin.marinas, christoffer.dall, linux-arm-kernel,
linux-kernel, marc.zyngier, pbonzini, linux, will.deacon
On Sat, Sep 14, 2013 at 02:10:55PM +0200, Andrew Jones wrote:
> Drop the _ARM_ part of the name. We can then introduce a config option
> like this to aarch64 and other arches using the same name - allowing
> grep to show them all. Also update the help text to describe the option
> more completely.
>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
> arch/arm/include/asm/kvm_host.h | 4 ++--
> arch/arm/kvm/Kconfig | 8 ++++----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 7d22517d80711..c614d3eb176c6 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -25,8 +25,8 @@
> #include <asm/fpstate.h>
> #include <kvm/arm_arch_timer.h>
>
> -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> +#if defined(CONFIG_KVM_MAX_VCPUS)
> +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
> #else
> #define KVM_MAX_VCPUS 0
> #endif
> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> index ebf5015508b52..de63bfccb3eb5 100644
> --- a/arch/arm/kvm/Kconfig
> +++ b/arch/arm/kvm/Kconfig
> @@ -40,16 +40,16 @@ config KVM_ARM_HOST
> ---help---
> Provides host support for ARM processors.
>
> -config KVM_ARM_MAX_VCPUS
> +config KVM_MAX_VCPUS
> int "Number maximum supported virtual CPUs per VM"
> depends on KVM_ARM_HOST
> default 4
> help
> Static number of max supported virtual CPUs per VM.
>
> - If you choose a high number, the vcpu structures will be quite
> - large, so only choose a reasonable number that you expect to
> - actually use.
I do no see why on ARM vcpu structure size depends on KVM_ARM_MAX_VCPUS.
Can somebody point me to it.
> + The default is set to the highest number of vcpus that
> + current hardware supports. Set to a lower number to save
> + some resources. Set to a higher number to test scalability.
>
> config KVM_ARM_VGIC
> bool "KVM support for Virtual GIC"
> --
> 1.8.1.4
--
Gleb.
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-15 9:30 ` Gleb Natapov
@ 2013-09-16 8:09 ` Marc Zyngier
2013-09-16 8:32 ` Gleb Natapov
0 siblings, 1 reply; 17+ messages in thread
From: Marc Zyngier @ 2013-09-16 8:09 UTC (permalink / raw)
To: Gleb Natapov
Cc: Andrew Jones, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Catalin Marinas, christoffer.dall@linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, pbonzini@redhat.com,
linux@arm.linux.org.uk, Will Deacon
On 15/09/13 10:30, Gleb Natapov wrote:
> On Sat, Sep 14, 2013 at 02:10:55PM +0200, Andrew Jones wrote:
>> Drop the _ARM_ part of the name. We can then introduce a config option
>> like this to aarch64 and other arches using the same name - allowing
>> grep to show them all. Also update the help text to describe the option
>> more completely.
>>
>> Signed-off-by: Andrew Jones <drjones@redhat.com>
>> ---
>> arch/arm/include/asm/kvm_host.h | 4 ++--
>> arch/arm/kvm/Kconfig | 8 ++++----
>> 2 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>> index 7d22517d80711..c614d3eb176c6 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -25,8 +25,8 @@
>> #include <asm/fpstate.h>
>> #include <kvm/arm_arch_timer.h>
>>
>> -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
>> -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
>> +#if defined(CONFIG_KVM_MAX_VCPUS)
>> +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
>> #else
>> #define KVM_MAX_VCPUS 0
>> #endif
>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>> index ebf5015508b52..de63bfccb3eb5 100644
>> --- a/arch/arm/kvm/Kconfig
>> +++ b/arch/arm/kvm/Kconfig
>> @@ -40,16 +40,16 @@ config KVM_ARM_HOST
>> ---help---
>> Provides host support for ARM processors.
>>
>> -config KVM_ARM_MAX_VCPUS
>> +config KVM_MAX_VCPUS
>> int "Number maximum supported virtual CPUs per VM"
>> depends on KVM_ARM_HOST
>> default 4
>> help
>> Static number of max supported virtual CPUs per VM.
>>
>> - If you choose a high number, the vcpu structures will be quite
>> - large, so only choose a reasonable number that you expect to
>> - actually use.
> I do no see why on ARM vcpu structure size depends on KVM_ARM_MAX_VCPUS.
> Can somebody point me to it.
There's a number of indirections, but here you go:
arch/arm/include/asm/kvm_host.h:#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
include/kvm/arm_vgic.h:#define VGIC_MAX_CPUS KVM_MAX_VCPUS
include/kvm/arm_vgic.h:#if (VGIC_MAX_CPUS > 8)
include/kvm/arm_vgic.h: } percpu[VGIC_MAX_CPUS];
include/kvm/arm_vgic.h: u32 percpu[VGIC_MAX_CPUS][VGIC_NR_PRIVATE_IRQS / 4];
include/kvm/arm_vgic.h: u8 irq_sgi_sources[VGIC_MAX_CPUS][VGIC_NR_SGIS];
include/kvm/arm_vgic.h: struct vgic_bitmap irq_spi_target[VGIC_MAX_CPUS];
Basically, the GIC emulation data structures are sized on the number of VCPUs
(as well as the number of supported interrupts).
M.
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-16 8:09 ` Marc Zyngier
@ 2013-09-16 8:32 ` Gleb Natapov
2013-09-16 8:49 ` Marc Zyngier
0 siblings, 1 reply; 17+ messages in thread
From: Gleb Natapov @ 2013-09-16 8:32 UTC (permalink / raw)
To: Marc Zyngier
Cc: Andrew Jones, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Catalin Marinas, christoffer.dall@linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, pbonzini@redhat.com,
linux@arm.linux.org.uk, Will Deacon
On Mon, Sep 16, 2013 at 09:09:27AM +0100, Marc Zyngier wrote:
> On 15/09/13 10:30, Gleb Natapov wrote:
> > On Sat, Sep 14, 2013 at 02:10:55PM +0200, Andrew Jones wrote:
> >> Drop the _ARM_ part of the name. We can then introduce a config option
> >> like this to aarch64 and other arches using the same name - allowing
> >> grep to show them all. Also update the help text to describe the option
> >> more completely.
> >>
> >> Signed-off-by: Andrew Jones <drjones@redhat.com>
> >> ---
> >> arch/arm/include/asm/kvm_host.h | 4 ++--
> >> arch/arm/kvm/Kconfig | 8 ++++----
> >> 2 files changed, 6 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> >> index 7d22517d80711..c614d3eb176c6 100644
> >> --- a/arch/arm/include/asm/kvm_host.h
> >> +++ b/arch/arm/include/asm/kvm_host.h
> >> @@ -25,8 +25,8 @@
> >> #include <asm/fpstate.h>
> >> #include <kvm/arm_arch_timer.h>
> >>
> >> -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> >> -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> >> +#if defined(CONFIG_KVM_MAX_VCPUS)
> >> +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
> >> #else
> >> #define KVM_MAX_VCPUS 0
> >> #endif
> >> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> >> index ebf5015508b52..de63bfccb3eb5 100644
> >> --- a/arch/arm/kvm/Kconfig
> >> +++ b/arch/arm/kvm/Kconfig
> >> @@ -40,16 +40,16 @@ config KVM_ARM_HOST
> >> ---help---
> >> Provides host support for ARM processors.
> >>
> >> -config KVM_ARM_MAX_VCPUS
> >> +config KVM_MAX_VCPUS
> >> int "Number maximum supported virtual CPUs per VM"
> >> depends on KVM_ARM_HOST
> >> default 4
> >> help
> >> Static number of max supported virtual CPUs per VM.
> >>
> >> - If you choose a high number, the vcpu structures will be quite
> >> - large, so only choose a reasonable number that you expect to
> >> - actually use.
> > I do no see why on ARM vcpu structure size depends on KVM_ARM_MAX_VCPUS.
> > Can somebody point me to it.
>
> There's a number of indirections, but here you go:
> arch/arm/include/asm/kvm_host.h:#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
>
> include/kvm/arm_vgic.h:#define VGIC_MAX_CPUS KVM_MAX_VCPUS
>
> include/kvm/arm_vgic.h:#if (VGIC_MAX_CPUS > 8)
> include/kvm/arm_vgic.h: } percpu[VGIC_MAX_CPUS];
> include/kvm/arm_vgic.h: u32 percpu[VGIC_MAX_CPUS][VGIC_NR_PRIVATE_IRQS / 4];
> include/kvm/arm_vgic.h: u8 irq_sgi_sources[VGIC_MAX_CPUS][VGIC_NR_SGIS];
> include/kvm/arm_vgic.h: struct vgic_bitmap irq_spi_target[VGIC_MAX_CPUS];
>
> Basically, the GIC emulation data structures are sized on the number of VCPUs
> (as well as the number of supported interrupts).
>
But vgic is per VM though, not per cpu as far as I can see, so the
overhead is also per VM, no? Is VGIC_MAX_CPUS limit architectural or
juts an implementation detail?
--
Gleb.
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-16 8:32 ` Gleb Natapov
@ 2013-09-16 8:49 ` Marc Zyngier
0 siblings, 0 replies; 17+ messages in thread
From: Marc Zyngier @ 2013-09-16 8:49 UTC (permalink / raw)
To: Gleb Natapov
Cc: Andrew Jones, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Catalin Marinas, christoffer.dall@linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, pbonzini@redhat.com,
linux@arm.linux.org.uk, Will Deacon
On 16/09/13 09:32, Gleb Natapov wrote:
> On Mon, Sep 16, 2013 at 09:09:27AM +0100, Marc Zyngier wrote:
>> On 15/09/13 10:30, Gleb Natapov wrote:
>>> On Sat, Sep 14, 2013 at 02:10:55PM +0200, Andrew Jones wrote:
>>>> Drop the _ARM_ part of the name. We can then introduce a config option
>>>> like this to aarch64 and other arches using the same name - allowing
>>>> grep to show them all. Also update the help text to describe the option
>>>> more completely.
>>>>
>>>> Signed-off-by: Andrew Jones <drjones@redhat.com>
>>>> ---
>>>> arch/arm/include/asm/kvm_host.h | 4 ++--
>>>> arch/arm/kvm/Kconfig | 8 ++++----
>>>> 2 files changed, 6 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
>>>> index 7d22517d80711..c614d3eb176c6 100644
>>>> --- a/arch/arm/include/asm/kvm_host.h
>>>> +++ b/arch/arm/include/asm/kvm_host.h
>>>> @@ -25,8 +25,8 @@
>>>> #include <asm/fpstate.h>
>>>> #include <kvm/arm_arch_timer.h>
>>>>
>>>> -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
>>>> -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
>>>> +#if defined(CONFIG_KVM_MAX_VCPUS)
>>>> +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
>>>> #else
>>>> #define KVM_MAX_VCPUS 0
>>>> #endif
>>>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>>>> index ebf5015508b52..de63bfccb3eb5 100644
>>>> --- a/arch/arm/kvm/Kconfig
>>>> +++ b/arch/arm/kvm/Kconfig
>>>> @@ -40,16 +40,16 @@ config KVM_ARM_HOST
>>>> ---help---
>>>> Provides host support for ARM processors.
>>>>
>>>> -config KVM_ARM_MAX_VCPUS
>>>> +config KVM_MAX_VCPUS
>>>> int "Number maximum supported virtual CPUs per VM"
>>>> depends on KVM_ARM_HOST
>>>> default 4
>>>> help
>>>> Static number of max supported virtual CPUs per VM.
>>>>
>>>> - If you choose a high number, the vcpu structures will be quite
>>>> - large, so only choose a reasonable number that you expect to
>>>> - actually use.
>>> I do no see why on ARM vcpu structure size depends on KVM_ARM_MAX_VCPUS.
>>> Can somebody point me to it.
>>
>> There's a number of indirections, but here you go:
>> arch/arm/include/asm/kvm_host.h:#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
>>
>> include/kvm/arm_vgic.h:#define VGIC_MAX_CPUS KVM_MAX_VCPUS
>>
>> include/kvm/arm_vgic.h:#if (VGIC_MAX_CPUS > 8)
>> include/kvm/arm_vgic.h: } percpu[VGIC_MAX_CPUS];
>> include/kvm/arm_vgic.h: u32 percpu[VGIC_MAX_CPUS][VGIC_NR_PRIVATE_IRQS / 4];
>> include/kvm/arm_vgic.h: u8 irq_sgi_sources[VGIC_MAX_CPUS][VGIC_NR_SGIS];
>> include/kvm/arm_vgic.h: struct vgic_bitmap irq_spi_target[VGIC_MAX_CPUS];
>>
>> Basically, the GIC emulation data structures are sized on the number of VCPUs
>> (as well as the number of supported interrupts).
>>
> But vgic is per VM though, not per cpu as far as I can see, so the
> overhead is also per VM, no? Is VGIC_MAX_CPUS limit architectural or
> juts an implementation detail?
Indeed, the MAX_VCPU overhead is per VM. The MAX_IRQS overhead is both
per-vm and per-vcpu.
The GICv2 architecture has a limit of 8 CPUs - not at all an
implementation detail. GICv3 remove this limitation.
M.
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-14 12:10 ` [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS Andrew Jones
2013-09-15 9:30 ` Gleb Natapov
@ 2013-09-17 21:42 ` Christoffer Dall
2013-09-24 14:09 ` [PATCH v2] " Andrew Jones
2 siblings, 0 replies; 17+ messages in thread
From: Christoffer Dall @ 2013-09-17 21:42 UTC (permalink / raw)
To: Andrew Jones
Cc: kvmarm, kvm, catalin.marinas, gleb, linux-arm-kernel,
linux-kernel, marc.zyngier, pbonzini, linux, will.deacon
On Sat, Sep 14, 2013 at 02:10:55PM +0200, Andrew Jones wrote:
> Drop the _ARM_ part of the name. We can then introduce a config option
> like this to aarch64 and other arches using the same name - allowing
> grep to show them all. Also update the help text to describe the option
> more completely.
>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
> arch/arm/include/asm/kvm_host.h | 4 ++--
> arch/arm/kvm/Kconfig | 8 ++++----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 7d22517d80711..c614d3eb176c6 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -25,8 +25,8 @@
> #include <asm/fpstate.h>
> #include <kvm/arm_arch_timer.h>
>
> -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> +#if defined(CONFIG_KVM_MAX_VCPUS)
> +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
> #else
> #define KVM_MAX_VCPUS 0
> #endif
> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> index ebf5015508b52..de63bfccb3eb5 100644
> --- a/arch/arm/kvm/Kconfig
> +++ b/arch/arm/kvm/Kconfig
> @@ -40,16 +40,16 @@ config KVM_ARM_HOST
> ---help---
> Provides host support for ARM processors.
>
> -config KVM_ARM_MAX_VCPUS
> +config KVM_MAX_VCPUS
> int "Number maximum supported virtual CPUs per VM"
> depends on KVM_ARM_HOST
> default 4
> help
> Static number of max supported virtual CPUs per VM.
>
> - If you choose a high number, the vcpu structures will be quite
> - large, so only choose a reasonable number that you expect to
> - actually use.
> + The default is set to the highest number of vcpus that
> + current hardware supports. Set to a lower number to save
> + some resources. Set to a higher number to test scalability.
Consider rephrasing the "Set to a lower number..." sentence to something
like "Choosing a lower number decreases the size of the VM data
structure.".
Also, please rephrase or get rid of the "Set to a higher number to test
scalability." sentence; you increase this value to be able to be able to
run more VCPUs (for whatever reason).
--
Christoffer
^ permalink raw reply [flat|nested] 17+ messages in thread
* [PATCH v2] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-14 12:10 ` [PATCH 2/3] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS Andrew Jones
2013-09-15 9:30 ` Gleb Natapov
2013-09-17 21:42 ` Christoffer Dall
@ 2013-09-24 14:09 ` Andrew Jones
2013-09-25 19:31 ` Christoffer Dall
2 siblings, 1 reply; 17+ messages in thread
From: Andrew Jones @ 2013-09-24 14:09 UTC (permalink / raw)
To: kvmarm, kvm
Cc: catalin.marinas, christoffer.dall, gleb, linux-arm-kernel,
linux-kernel, marc.zyngier, pbonzini, linux, will.deacon
Drop the _ARM_ part of the name. We can then introduce a config option
like this to aarch64 and other arches using the same name - allowing
grep to show them all. Also update the help text to describe the option
more completely.
Signed-off-by: Andrew Jones <drjones@redhat.com>
---
v2: reword help text some more
---
arch/arm/include/asm/kvm_host.h | 4 ++--
arch/arm/kvm/Kconfig | 9 +++++----
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 7d22517d80711..c614d3eb176c6 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -25,8 +25,8 @@
#include <asm/fpstate.h>
#include <kvm/arm_arch_timer.h>
-#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
-#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
+#if defined(CONFIG_KVM_MAX_VCPUS)
+#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
#else
#define KVM_MAX_VCPUS 0
#endif
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index ebf5015508b52..8e56ccf45edce 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -40,16 +40,17 @@ config KVM_ARM_HOST
---help---
Provides host support for ARM processors.
-config KVM_ARM_MAX_VCPUS
+config KVM_MAX_VCPUS
int "Number maximum supported virtual CPUs per VM"
depends on KVM_ARM_HOST
default 4
help
Static number of max supported virtual CPUs per VM.
- If you choose a high number, the vcpu structures will be quite
- large, so only choose a reasonable number that you expect to
- actually use.
+ The default is set to the highest number of vcpus that
+ current hardware supports. Choosing a lower number decreases
+ the size of the VM data structure. This number may also be
+ increased.
config KVM_ARM_VGIC
bool "KVM support for Virtual GIC"
--
1.8.1.4
^ permalink raw reply related [flat|nested] 17+ messages in thread
* Re: [PATCH v2] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-24 14:09 ` [PATCH v2] " Andrew Jones
@ 2013-09-25 19:31 ` Christoffer Dall
2013-09-26 7:54 ` Andrew Jones
0 siblings, 1 reply; 17+ messages in thread
From: Christoffer Dall @ 2013-09-25 19:31 UTC (permalink / raw)
To: Andrew Jones
Cc: kvmarm, kvm, catalin.marinas, gleb, linux-arm-kernel,
linux-kernel, marc.zyngier, pbonzini, linux, will.deacon
On Tue, Sep 24, 2013 at 04:09:28PM +0200, Andrew Jones wrote:
> Drop the _ARM_ part of the name. We can then introduce a config option
> like this to aarch64 and other arches using the same name - allowing
> grep to show them all. Also update the help text to describe the option
> more completely.
>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
>
> ---
> v2: reword help text some more
> ---
> arch/arm/include/asm/kvm_host.h | 4 ++--
> arch/arm/kvm/Kconfig | 9 +++++----
> 2 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 7d22517d80711..c614d3eb176c6 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -25,8 +25,8 @@
> #include <asm/fpstate.h>
> #include <kvm/arm_arch_timer.h>
>
> -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> +#if defined(CONFIG_KVM_MAX_VCPUS)
> +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
> #else
> #define KVM_MAX_VCPUS 0
> #endif
> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> index ebf5015508b52..8e56ccf45edce 100644
> --- a/arch/arm/kvm/Kconfig
> +++ b/arch/arm/kvm/Kconfig
> @@ -40,16 +40,17 @@ config KVM_ARM_HOST
> ---help---
> Provides host support for ARM processors.
>
> -config KVM_ARM_MAX_VCPUS
> +config KVM_MAX_VCPUS
> int "Number maximum supported virtual CPUs per VM"
> depends on KVM_ARM_HOST
> default 4
> help
> Static number of max supported virtual CPUs per VM.
>
> - If you choose a high number, the vcpu structures will be quite
> - large, so only choose a reasonable number that you expect to
> - actually use.
> + The default is set to the highest number of vcpus that
> + current hardware supports. Choosing a lower number decreases
> + the size of the VM data structure. This number may also be
> + increased.
>
Maybe I'm being forgetful, but what do you mean by "This number may also
be increased" ?
-Christoffer
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v2] arm32: kvm: rename CONFIG_KVM_ARM_MAX_VCPUS
2013-09-25 19:31 ` Christoffer Dall
@ 2013-09-26 7:54 ` Andrew Jones
0 siblings, 0 replies; 17+ messages in thread
From: Andrew Jones @ 2013-09-26 7:54 UTC (permalink / raw)
To: Christoffer Dall
Cc: kvmarm, kvm, catalin.marinas, gleb, linux-arm-kernel,
linux-kernel, marc.zyngier, pbonzini, linux, will.deacon
On Wed, Sep 25, 2013 at 12:31:27PM -0700, Christoffer Dall wrote:
> On Tue, Sep 24, 2013 at 04:09:28PM +0200, Andrew Jones wrote:
> > Drop the _ARM_ part of the name. We can then introduce a config option
> > like this to aarch64 and other arches using the same name - allowing
> > grep to show them all. Also update the help text to describe the option
> > more completely.
> >
> > Signed-off-by: Andrew Jones <drjones@redhat.com>
> >
> > ---
> > v2: reword help text some more
> > ---
> > arch/arm/include/asm/kvm_host.h | 4 ++--
> > arch/arm/kvm/Kconfig | 9 +++++----
> > 2 files changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> > index 7d22517d80711..c614d3eb176c6 100644
> > --- a/arch/arm/include/asm/kvm_host.h
> > +++ b/arch/arm/include/asm/kvm_host.h
> > @@ -25,8 +25,8 @@
> > #include <asm/fpstate.h>
> > #include <kvm/arm_arch_timer.h>
> >
> > -#if defined(CONFIG_KVM_ARM_MAX_VCPUS)
> > -#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
> > +#if defined(CONFIG_KVM_MAX_VCPUS)
> > +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
> > #else
> > #define KVM_MAX_VCPUS 0
> > #endif
> > diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> > index ebf5015508b52..8e56ccf45edce 100644
> > --- a/arch/arm/kvm/Kconfig
> > +++ b/arch/arm/kvm/Kconfig
> > @@ -40,16 +40,17 @@ config KVM_ARM_HOST
> > ---help---
> > Provides host support for ARM processors.
> >
> > -config KVM_ARM_MAX_VCPUS
> > +config KVM_MAX_VCPUS
> > int "Number maximum supported virtual CPUs per VM"
> > depends on KVM_ARM_HOST
> > default 4
> > help
> > Static number of max supported virtual CPUs per VM.
> >
> > - If you choose a high number, the vcpu structures will be quite
> > - large, so only choose a reasonable number that you expect to
> > - actually use.
> > + The default is set to the highest number of vcpus that
> > + current hardware supports. Choosing a lower number decreases
> > + the size of the VM data structure. This number may also be
> > + increased.
> >
> Maybe I'm being forgetful, but what do you mean by "This number may also
> be increased" ?
Originally I was proposing we write 'increase for scalability testing',
as would be the purpose on the x86 side. However, you suggested it can
be increased for other purposes, although you didn't mention what. I just
dropped the 'scalability testing' to allow users to fill the blank in
themselves. If it doesn't really make sense on arm to increase this
beyond what hardware supports, then we can drop the 'increase' completely
and add a
range 1 <same-as-default>
to the Kconfig entry instead.
drew
^ permalink raw reply [flat|nested] 17+ messages in thread