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authorMing Lei <ming.lei@canonical.com>2015-09-02 09:31:21 +0300
committerMarc Zyngier <marc.zyngier@arm.com>2015-09-17 15:13:27 +0300
commitef748917b529847277f07c98c55e1c0ce416449f (patch)
treef121d6fefff690152f4e8257c67ad7d807fa991b /include/kvm
parent34c3faa353db8f5d3ce9966cf854d5643c64c4db (diff)
downloadlinux-ef748917b529847277f07c98c55e1c0ce416449f.tar.xz
arm/arm64: KVM: Remove 'config KVM_ARM_MAX_VCPUS'
This patch removes config option of KVM_ARM_MAX_VCPUS, and like other ARCHs, just choose the maximum allowed value from hardware, and follows the reasons: 1) from distribution view, the option has to be defined as the max allowed value because it need to meet all kinds of virtulization applications and need to support most of SoCs; 2) using a bigger value doesn't introduce extra memory consumption, and the help text in Kconfig isn't accurate because kvm_vpu structure isn't allocated until request of creating VCPU is sent from QEMU; 3) the main effect is that the field of vcpus[] in 'struct kvm' becomes a bit bigger(sizeof(void *) per vcpu) and need more cache lines to hold the structure, but 'struct kvm' is one generic struct, and it has worked well on other ARCHs already in this way. Also, the world switch frequecy is often low, for example, it is ~2000 when running kernel building load in VM from APM xgene KVM host, so the effect is very small, and the difference can't be observed in my test at all. Cc: Dann Frazier <dann.frazier@canonical.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'include/kvm')
-rw-r--r--include/kvm/arm_vgic.h6
1 files changed, 1 insertions, 5 deletions
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index d901f1a47be6..4e14dac282bb 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -35,11 +35,7 @@
#define VGIC_V3_MAX_LRS 16
#define VGIC_MAX_IRQS 1024
#define VGIC_V2_MAX_CPUS 8
-
-/* Sanity checks... */
-#if (KVM_MAX_VCPUS > 255)
-#error Too many KVM VCPUs, the VGIC only supports up to 255 VCPUs for now
-#endif
+#define VGIC_V3_MAX_CPUS 255
#if (VGIC_NR_IRQS_LEGACY & 31)
#error "VGIC_NR_IRQS must be a multiple of 32"