kvm defines memory in "slots", more or less corresponding to the DIMM slots.
this allows us to:
- avoid the VGA hole at 640K
- add a pci framebuffer at runtime
- hotplug memory
Signed-off-by: Yaniv Kamay <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
Index: linux-2.6/drivers/kvm/kvm_main.c
===================================================================
--- linux-2.6.orig/drivers/kvm/kvm_main.c
+++ linux-2.6/drivers/kvm/kvm_main.c
@@ -1039,6 +1039,211 @@ static void vcpu_put_rsp_rip(struct kvm_
vmcs_writel(GUEST_RIP, vcpu->rip);
}
+/*
+ * Allocate some memory and give it an address in the guest physical address
+ * space.
+ *
+ * Discontiguous memory is allowed, mostly for framebuffers.
+ */
+static int kvm_dev_ioctl_set_memory_region(struct kvm *kvm,
+ struct kvm_memory_region *mem)
+{
+ int r;
+ gfn_t base_gfn;
+ unsigned long npages;
+ unsigned long i;
+ struct kvm_memory_slot *memslot;
+ struct kvm_memory_slot old, new;
+ int memory_config_version;
+
+ r = -EINVAL;
+ /* General sanity checks */
+ if (mem->memory_size & (PAGE_SIZE - 1))
+ goto out;
+ if (mem->guest_phys_addr & (PAGE_SIZE - 1))
+ goto out;
+ if (mem->slot >= KVM_MEMORY_SLOTS)
+ goto out;
+ if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
+ goto out;
+
+ memslot = &kvm->memslots[mem->slot];
+ base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
+ npages = mem->memory_size >> PAGE_SHIFT;
+
+ if (!npages)
+ mem->flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
+
+raced:
+ spin_lock(&kvm->lock);
+
+ memory_config_version = kvm->memory_config_version;
+ new = old = *memslot;
+
+ new.base_gfn = base_gfn;
+ new.npages = npages;
+ new.flags = mem->flags;
+
+ /* Disallow changing a memory slot's size. */
+ r = -EINVAL;
+ if (npages && old.npages && npages != old.npages)
+ goto out_unlock;
+
+ /* Check for overlaps */
+ r = -EEXIST;
+ for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
+ struct kvm_memory_slot *s = &kvm->memslots[i];
+
+ if (s == memslot)
+ continue;
+ if (!((base_gfn + npages <= s->base_gfn) ||
+ (base_gfn >= s->base_gfn + s->npages)))
+ goto out_unlock;
+ }
+ /*
+ * Do memory allocations outside lock. memory_config_version will
+ * detect any races.
+ */
+ spin_unlock(&kvm->lock);
+
+ /* Deallocate if slot is being removed */
+ if (!npages)
+ new.phys_mem = 0;
+
+ /* Free page dirty bitmap if unneeded */
+ if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
+ new.dirty_bitmap = 0;
+
+ r = -ENOMEM;
+
+ /* Allocate if a slot is being created */
+ if (npages && !new.phys_mem) {
+ new.phys_mem = vmalloc(npages * sizeof(struct page *));
+
+ if (!new.phys_mem)
+ goto out_free;
+
+ memset(new.phys_mem, 0, npages * sizeof(struct page *));
+ for (i = 0; i < npages; ++i) {
+ new.phys_mem[i] = alloc_page(GFP_HIGHUSER);
+ if (!new.phys_mem[i])
+ goto out_free;
+ }
+ }
+
+ /* Allocate page dirty bitmap if needed */
+ if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
+ unsigned dirty_bytes = ALIGN(npages, BITS_PER_LONG) / 8;
+
+ new.dirty_bitmap = vmalloc(dirty_bytes);
+ if (!new.dirty_bitmap)
+ goto out_free;
+ memset(new.dirty_bitmap, 0, dirty_bytes);
+ }
+
+ spin_lock(&kvm->lock);
+
+ if (memory_config_version != kvm->memory_config_version) {
+ spin_unlock(&kvm->lock);
+ kvm_free_physmem_slot(&new, &old);
+ goto raced;
+ }
+
+ r = -EAGAIN;
+ if (kvm->busy)
+ goto out_unlock;
+
+ if (mem->slot >= kvm->nmemslots)
+ kvm->nmemslots = mem->slot + 1;
+
+ *memslot = new;
+ ++kvm->memory_config_version;
+
+ spin_unlock(&kvm->lock);
+
+ for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+ struct kvm_vcpu *vcpu;
+
+ vcpu = vcpu_load(kvm, i);
+ if (!vcpu)
+ continue;
+ kvm_mmu_reset_context(vcpu);
+ vcpu_put(vcpu);
+ }
+
+ kvm_free_physmem_slot(&old, &new);
+ return 0;
+
+out_unlock:
+ spin_unlock(&kvm->lock);
+out_free:
+ kvm_free_physmem_slot(&new, &old);
+out:
+ return r;
+}
+
+/*
+ * Get (and clear) the dirty memory log for a memory slot.
+ */
+static int kvm_dev_ioctl_get_dirty_log(struct kvm *kvm,
+ struct kvm_dirty_log *log)
+{
+ struct kvm_memory_slot *memslot;
+ int r, i;
+ int n;
+ unsigned long any = 0;
+
+ spin_lock(&kvm->lock);
+
+ /*
+ * Prevent changes to guest memory configuration even while the lock
+ * is not taken.
+ */
+ ++kvm->busy;
+ spin_unlock(&kvm->lock);
+ r = -EINVAL;
+ if (log->slot >= KVM_MEMORY_SLOTS)
+ goto out;
+
+ memslot = &kvm->memslots[log->slot];
+ r = -ENOENT;
+ if (!memslot->dirty_bitmap)
+ goto out;
+
+ n = ALIGN(memslot->npages, 8) / 8;
+
+ for (i = 0; !any && i < n; ++i)
+ any = memslot->dirty_bitmap[i];
+
+ r = -EFAULT;
+ if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
+ goto out;
+
+
+ if (any) {
+ spin_lock(&kvm->lock);
+ kvm_mmu_slot_remove_write_access(kvm, log->slot);
+ spin_unlock(&kvm->lock);
+ memset(memslot->dirty_bitmap, 0, n);
+ for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+ struct kvm_vcpu *vcpu = vcpu_load(kvm, i);
+
+ if (!vcpu)
+ continue;
+ flush_guest_tlb(vcpu);
+ vcpu_put(vcpu);
+ }
+ }
+
+ r = 0;
+
+out:
+ spin_lock(&kvm->lock);
+ --kvm->busy;
+ spin_unlock(&kvm->lock);
+ return r;
+}
+
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
int i;
@@ -1201,6 +1406,28 @@ static long kvm_dev_ioctl(struct file *f
int r = -EINVAL;
switch (ioctl) {
+ case KVM_SET_MEMORY_REGION: {
+ struct kvm_memory_region kvm_mem;
+
+ r = -EFAULT;
+ if (copy_from_user(&kvm_mem, (void *)arg, sizeof kvm_mem))
+ goto out;
+ r = kvm_dev_ioctl_set_memory_region(kvm, &kvm_mem);
+ if (r)
+ goto out;
+ break;
+ }
+ case KVM_GET_DIRTY_LOG: {
+ struct kvm_dirty_log log;
+
+ r = -EFAULT;
+ if (copy_from_user(&log, (void *)arg, sizeof log))
+ goto out;
+ r = kvm_dev_ioctl_get_dirty_log(kvm, &log);
+ if (r)
+ goto out;
+ break;
+ }
default:
;
}
-
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