From: Jan Kiszka Date: Fri, 24 Apr 2009 16:05:09 +0000 (+0000) Subject: KVM: Fix overlapping check for memory slots X-Git-Tag: v2.6.29.3~49 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d6ad1be8584fd05ba44539d2fba421564abb46b;p=thirdparty%2Fkernel%2Fstable.git KVM: Fix overlapping check for memory slots upstream commit: 4cd481f68dde99ac416003b825c835f71e364393 When checking for overlapping slots on registration of a new one, kvm currently also considers zero-length (ie. deleted) slots and rejects requests incorrectly. This finally denies user space from joining slots. Fix the check by skipping deleted slots and advertise this via a KVM_CAP_JOIN_MEMORY_REGIONS_WORKS. Cc: stable@kernel.org Signed-off-by: Jan Kiszka Signed-off-by: Avi Kivity Signed-off-by: Chris Wright --- diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 0424326f16796..c344599d1be0e 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -396,6 +396,8 @@ struct kvm_trace_rec { #ifdef __KVM_HAVE_USER_NMI #define KVM_CAP_USER_NMI 22 #endif +/* Another bug in KVM_SET_USER_MEMORY_REGION fixed: */ +#define KVM_CAP_JOIN_MEMORY_REGIONS_WORKS 30 /* * ioctls for VM fds diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e02c48ba22241..d85642e2c74d9 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1005,7 +1005,7 @@ int __kvm_set_memory_region(struct kvm *kvm, for (i = 0; i < KVM_MEMORY_SLOTS; ++i) { struct kvm_memory_slot *s = &kvm->memslots[i]; - if (s == memslot) + if (s == memslot || !s->npages) continue; if (!((base_gfn + npages <= s->base_gfn) || (base_gfn >= s->base_gfn + s->npages))) @@ -1997,6 +1997,7 @@ static long kvm_dev_ioctl_check_extension_generic(long arg) switch (arg) { case KVM_CAP_USER_MEMORY: case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: + case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS: return 1; default: break;