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Commit 4cd481f6 authored by Jan Kiszka's avatar Jan Kiszka Committed by Avi Kivity
Browse files

KVM: Fix overlapping check for memory slots 



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: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent bf47a760

include/linux/kvm.h

+2 −0
Original line number Diff line number Diff line
@@ -409,6 +409,8 @@ struct kvm_trace_rec { 
#ifdef __KVM_HAVE_DEVICE_ASSIGNMENT

#define KVM_CAP_DEVICE_DEASSIGNMENT 27

#endif

/* Another bug in KVM_SET_USER_MEMORY_REGION fixed: */

#define KVM_CAP_JOIN_MEMORY_REGIONS_WORKS 30



#ifdef KVM_CAP_IRQ_ROUTING

virt/kvm/kvm_main.c

+2 −1
Original line number Diff line number Diff line
@@ -961,7 +961,7 @@ 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)))
@@ -1983,6 +1983,7 @@ 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;

#ifdef CONFIG_HAVE_KVM_IRQCHIP

	case KVM_CAP_IRQ_ROUTING: