| Message ID | 20170413201951.11939-5-rkrcmar@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/13/2017 10:19 PM, Radim Krčmář wrote: > The only user of KVM_MAX_VCPU is switched to kvm->max_vcpu. > > The limit could have been INT_MAX as it makes no difference, but there > is no point in making it bigger than KVM_MAX_VCPU_ID. > > Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/irq_comm.c | 4 ++-- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 2cc5ec7cc6f5..eeeb88eedabf 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -38,6 +38,7 @@ > #define KVM_MAX_VCPUS 288 > #define KVM_SOFT_MAX_VCPUS 240 > #define KVM_MAX_VCPU_ID 1023 > +#define KVM_CONFIGURABLE_MAX_VCPUS KVM_MAX_VCPU_ID > #define KVM_USER_MEM_SLOTS 509 > /* memory slots that are not exposed to userspace */ > #define KVM_PRIVATE_MEM_SLOTS 3 > diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c > index 4517a4c2ac3a..a7baeb44539a 100644 > --- a/arch/x86/kvm/irq_comm.c > +++ b/arch/x86/kvm/irq_comm.c > @@ -60,7 +60,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, > { > int i, r = -1; > struct kvm_vcpu *vcpu, *lowest = NULL; > - unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)]; > + unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(kvm->max_vcpus)]; Doesnt that allow unlimited stack usage?
2017-04-19 10:08+0200, Christian Borntraeger: > On 04/13/2017 10:19 PM, Radim Krčmář wrote: >> The only user of KVM_MAX_VCPU is switched to kvm->max_vcpu. >> >> The limit could have been INT_MAX as it makes no difference, but there >> is no point in making it bigger than KVM_MAX_VCPU_ID. >> >> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> >> --- >> arch/x86/include/asm/kvm_host.h | 1 + >> arch/x86/kvm/irq_comm.c | 4 ++-- >> 2 files changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index 2cc5ec7cc6f5..eeeb88eedabf 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -38,6 +38,7 @@ >> #define KVM_MAX_VCPUS 288 >> #define KVM_SOFT_MAX_VCPUS 240 >> #define KVM_MAX_VCPU_ID 1023 >> +#define KVM_CONFIGURABLE_MAX_VCPUS KVM_MAX_VCPU_ID >> #define KVM_USER_MEM_SLOTS 509 >> /* memory slots that are not exposed to userspace */ >> #define KVM_PRIVATE_MEM_SLOTS 3 >> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c >> index 4517a4c2ac3a..a7baeb44539a 100644 >> --- a/arch/x86/kvm/irq_comm.c >> +++ b/arch/x86/kvm/irq_comm.c >> @@ -60,7 +60,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, >> { >> int i, r = -1; >> struct kvm_vcpu *vcpu, *lowest = NULL; >> - unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)]; >> + unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(kvm->max_vcpus)]; > > Doesnt that allow unlimited stack usage? Right, it doesn't scale. kvm->max_vcpus is at most KVM_CONFIGURABLE_MAX_VCPUS, but that will be bigger than the stack. I'll allocate the bitmap in v2. Thanks.
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 2cc5ec7cc6f5..eeeb88eedabf 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -38,6 +38,7 @@ #define KVM_MAX_VCPUS 288 #define KVM_SOFT_MAX_VCPUS 240 #define KVM_MAX_VCPU_ID 1023 +#define KVM_CONFIGURABLE_MAX_VCPUS KVM_MAX_VCPU_ID #define KVM_USER_MEM_SLOTS 509 /* memory slots that are not exposed to userspace */ #define KVM_PRIVATE_MEM_SLOTS 3 diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c index 4517a4c2ac3a..a7baeb44539a 100644 --- a/arch/x86/kvm/irq_comm.c +++ b/arch/x86/kvm/irq_comm.c @@ -60,7 +60,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, { int i, r = -1; struct kvm_vcpu *vcpu, *lowest = NULL; - unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)]; + unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(kvm->max_vcpus)]; unsigned int dest_vcpus = 0; if (irq->dest_mode == 0 && irq->dest_id == 0xff && @@ -101,7 +101,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, if (dest_vcpus != 0) { int idx = kvm_vector_to_index(irq->vector, dest_vcpus, - dest_vcpu_bitmap, KVM_MAX_VCPUS); + dest_vcpu_bitmap, kvm->max_vcpus); lowest = kvm_get_vcpu(kvm, idx); }
The only user of KVM_MAX_VCPU is switched to kvm->max_vcpu. The limit could have been INT_MAX as it makes no difference, but there is no point in making it bigger than KVM_MAX_VCPU_ID. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/irq_comm.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-)