struct kvm_memory_slot is currently 52 bytes (LP64), not counting the
arch data. On x86 this means the memslot array to support a tiny 32+3
entries (user+private) is over 2k. We'd like to support more slots
so that we can support more assigned devices, but it doesn't make
sense to penalize everyone by using a statically allocated array.
This allows us to start introducing a grow-able array.
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
arch/ia64/kvm/kvm-ia64.c | 2 +-
arch/powerpc/kvm/book3s_hv.c | 2 +-
arch/x86/kvm/vmx.c | 1 +
arch/x86/kvm/x86.c | 4 +++-
include/linux/kvm_host.h | 9 ++++++---
virt/kvm/kvm_main.c | 10 ++++++----
6 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 012e5dd..96401b5 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1836,7 +1836,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
memslot = id_to_memslot(kvm->memslots, log->slot);
r = -ENOENT;
- if (!memslot->dirty_bitmap)
+ if (!memslots || !memslot->dirty_bitmap)
goto out;
kvm_ia64_sync_dirty_log(kvm, memslot);
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 56067db..0417190 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1267,7 +1267,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
memslot = id_to_memslot(kvm->memslots, log->slot);
r = -ENOENT;
- if (!memslot->dirty_bitmap)
+ if (!memslot || !memslot->dirty_bitmap)
goto out;
n = kvm_dirty_bitmap_bytes(memslot);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2bb9157..07fdd90 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2751,6 +2751,7 @@ static gva_t rmode_tss_base(struct kvm *kvm)
slots = kvm_memslots(kvm);
slot = id_to_memslot(slots, KVM_PRIVATE_MEM_SLOTS);
+ BUG_ON(!slot);
base_gfn = slot->base_gfn + slot->npages - 3;
return base_gfn << PAGE_SHIFT;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8765485..53fe9b2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3139,9 +3139,11 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
goto out;
memslot = id_to_memslot(kvm->memslots, log->slot);
+ r = -ENOENT;
+ if (!memslot)
+ goto out;
dirty_bitmap = memslot->dirty_bitmap;
- r = -ENOENT;
if (!dirty_bitmap)
goto out;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7b3d5c4..1955a4e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -313,6 +313,7 @@ struct kvm_irq_routing_table {};
* to get the memslot by its id.
*/
struct kvm_memslots {
+ int nmemslots;
u64 generation;
struct kvm_memory_slot memslots[KVM_MEM_SLOTS_NUM];
};
@@ -397,7 +398,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
#define kvm_for_each_memslot(memslot, slots) \
for (memslot = &slots->memslots[0]; \
- memslot < slots->memslots + KVM_MEM_SLOTS_NUM && memslot->npages;\
+ memslot < slots->memslots + slots->nmemslots && memslot->npages;\
memslot++)
int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id);
@@ -424,10 +425,12 @@ static inline struct kvm_memslots *kvm_memslots(struct kvm *kvm)
static inline struct kvm_memory_slot *
id_to_memslot(struct kvm_memslots *slots, int id)
{
- int index = slots->memslots[id].id_to_index;
struct kvm_memory_slot *slot;
- slot = &slots->memslots[index];
+ if (id >= slots->nmemslots)
+ return NULL;
+
+ slot = &slots->memslots[slots->memslots[id].id_to_index];
WARN_ON(slot->id != id);
return slot;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3ce2664..ebd3960 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -444,7 +444,9 @@ static void kvm_init_memslots_id(struct kvm *kvm)
int i;
struct kvm_memslots *slots = kvm->memslots;
- for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+ slots->nmemslots = KVM_MEM_SLOTS_NUM;
+
+ for (i = 0; i < kvm->memslots->nmemslots; i++)
slots->memslots[i].id_to_index = slots->memslots[i].id = i;
}
@@ -658,10 +660,10 @@ static void sort_memslots(struct kvm_memslots *slots)
{
int i;
- sort(slots->memslots, KVM_MEM_SLOTS_NUM,
+ sort(slots->memslots, slots->nmemslots,
sizeof(struct kvm_memory_slot), cmp_memslot, NULL);
- for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+ for (i = 0; i < slots->nmemslots; i++)
slots->memslots[slots->memslots[i].id].id_to_index = i;
}
@@ -898,7 +900,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
memslot = id_to_memslot(kvm->memslots, log->slot);
r = -ENOENT;
- if (!memslot->dirty_bitmap)
+ if (!memslot || !memslot->dirty_bitmap)
goto out;
n = kvm_dirty_bitmap_bytes(memslot);
--
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