| Message ID | 20210701154105.23215-2-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/kvm: add boot parameters for max vcpu configs | expand |
On Thu, Jul 01, 2021 at 05:41:00PM +0200, Juergen Gross wrote: > KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number > of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1 > elements. I don't think that's true. kvm_vm_ioctl_create_vcpu() refuses to create a VCPU with id==KVM_MAX_VCPU_ID. Documentation/virt/kvm/api.rst also states that "The vcpu id is an integer in the range [0, max_vcpu_id)." > > Note that this is currently no real problem, as KVM_MAX_VCPU_ID is > an odd number, resulting in always enough padding being available at > the end of those arrays. > > Nevertheless this should be fixed in order to avoid rare problems in > case someone is using an even number for KVM_MAX_VCPU_ID. > > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > arch/x86/kvm/ioapic.c | 2 +- > arch/x86/kvm/ioapic.h | 4 ++-- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c > index 698969e18fe3..ff005fe738a4 100644 > --- a/arch/x86/kvm/ioapic.c > +++ b/arch/x86/kvm/ioapic.c > @@ -96,7 +96,7 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic, > static void rtc_irq_eoi_tracking_reset(struct kvm_ioapic *ioapic) > { > ioapic->rtc_status.pending_eoi = 0; > - bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID); > + bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID + 1); > } > > static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic); > diff --git a/arch/x86/kvm/ioapic.h b/arch/x86/kvm/ioapic.h > index 660401700075..11e4065e1617 100644 > --- a/arch/x86/kvm/ioapic.h > +++ b/arch/x86/kvm/ioapic.h > @@ -43,13 +43,13 @@ struct kvm_vcpu; > > struct dest_map { > /* vcpu bitmap where IRQ has been sent */ > - DECLARE_BITMAP(map, KVM_MAX_VCPU_ID); > + DECLARE_BITMAP(map, KVM_MAX_VCPU_ID + 1); > > /* > * Vector sent to a given vcpu, only valid when > * the vcpu's bit in map is set > */ > - u8 vectors[KVM_MAX_VCPU_ID]; > + u8 vectors[KVM_MAX_VCPU_ID + 1]; > }; > > > -- > 2.26.2 >
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c index 698969e18fe3..ff005fe738a4 100644 --- a/arch/x86/kvm/ioapic.c +++ b/arch/x86/kvm/ioapic.c @@ -96,7 +96,7 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic, static void rtc_irq_eoi_tracking_reset(struct kvm_ioapic *ioapic) { ioapic->rtc_status.pending_eoi = 0; - bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID); + bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID + 1); } static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic); diff --git a/arch/x86/kvm/ioapic.h b/arch/x86/kvm/ioapic.h index 660401700075..11e4065e1617 100644 --- a/arch/x86/kvm/ioapic.h +++ b/arch/x86/kvm/ioapic.h @@ -43,13 +43,13 @@ struct kvm_vcpu; struct dest_map { /* vcpu bitmap where IRQ has been sent */ - DECLARE_BITMAP(map, KVM_MAX_VCPU_ID); + DECLARE_BITMAP(map, KVM_MAX_VCPU_ID + 1); /* * Vector sent to a given vcpu, only valid when * the vcpu's bit in map is set */ - u8 vectors[KVM_MAX_VCPU_ID]; + u8 vectors[KVM_MAX_VCPU_ID + 1]; };
KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1 elements. Note that this is currently no real problem, as KVM_MAX_VCPU_ID is an odd number, resulting in always enough padding being available at the end of those arrays. Nevertheless this should be fixed in order to avoid rare problems in case someone is using an even number for KVM_MAX_VCPU_ID. Signed-off-by: Juergen Gross <jgross@suse.com> --- arch/x86/kvm/ioapic.c | 2 +- arch/x86/kvm/ioapic.h | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)