Re: [PATCH RESEND] arm64: KVM: Add Kconfig option for max VCPUs per-Guest

On 12/12/13 16:12, Anup Patel wrote:

Current max VCPUs per-Guest is set to 4 which is preventing us from creating a Guest (or VM) with 8 VCPUs on Host (e.g. X-Gene Storm SOC) with 8 Host CPUs.

The correct value of max VCPUs per-Guest should be same as the max CPUs supported by GICv2 which is 8 but, increasing value of max VCPUs per-Guest can make things slower hence we add Kconfig option to let KVM users select appropriate max VCPUs per-Guest.

Signed-off-by: Anup Patel anup.patel@linaro.org Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org

Acked-by: Marc Zyngier marc.zyngier@arm.com

M.

---

arch/arm64/include/asm/kvm_host.h | 7 ++++++- arch/arm64/kvm/Kconfig | 11 +++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 5d85a02..0a1d697 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -26,7 +26,12 @@ #include <asm/kvm_asm.h> #include <asm/kvm_mmio.h> -#define KVM_MAX_VCPUS 4 +#if defined(CONFIG_KVM_ARM_MAX_VCPUS) +#define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS +#else +#define KVM_MAX_VCPUS 0 +#endif

#define KVM_USER_MEM_SLOTS 32 #define KVM_PRIVATE_MEM_SLOTS 4 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 4480ab3..8ba85e9 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -36,6 +36,17 @@ config KVM_ARM_HOST ---help--- Provides host support for ARM processors. +config KVM_ARM_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.
  

config KVM_ARM_VGIC bool depends on KVM_ARM_HOST && OF